psychology experiments in history

• The 25 Most Influential Psychological Experiments in History

While each year thousands and thousands of studies are completed in the many specialty areas of psychology, there are a handful that, over the years, have had a lasting impact in the psychological community as a whole. Some of these were dutifully conducted, keeping within the confines of ethical and practical guidelines. Others pushed the boundaries of human behavior during their psychological experiments and created controversies that still linger to this day. And still others were not designed to be true psychological experiments, but ended up as beacons to the psychological community in proving or disproving theories.

This is a list of the 25 most influential psychological experiments still being taught to psychology students of today.

1. A Class Divided

Study conducted by: jane elliott.

Study Conducted in 1968 in an Iowa classroom

Experiment Details: Jane Elliott’s famous experiment was inspired by the assassination of Dr. Martin Luther King Jr. and the inspirational life that he led. The third grade teacher developed an exercise, or better yet, a psychological experiment, to help her Caucasian students understand the effects of racism and prejudice.

Elliott divided her class into two separate groups: blue-eyed students and brown-eyed students. On the first day, she labeled the blue-eyed group as the superior group and from that point forward they had extra privileges, leaving the brown-eyed children to represent the minority group. She discouraged the groups from interacting and singled out individual students to stress the negative characteristics of the children in the minority group. What this exercise showed was that the children’s behavior changed almost instantaneously. The group of blue-eyed students performed better academically and even began bullying their brown-eyed classmates. The brown-eyed group experienced lower self-confidence and worse academic performance. The next day, she reversed the roles of the two groups and the blue-eyed students became the minority group.

At the end of the experiment, the children were so relieved that they were reported to have embraced one another and agreed that people should not be judged based on outward appearances. This exercise has since been repeated many times with similar outcomes.

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2. Asch Conformity Study

Study conducted by: dr. solomon asch.

Study Conducted in 1951 at Swarthmore College

Experiment Details: Dr. Solomon Asch conducted a groundbreaking study that was designed to evaluate a person’s likelihood to conform to a standard when there is pressure to do so.

A group of participants were shown pictures with lines of various lengths and were then asked a simple question: Which line is longest? The tricky part of this study was that in each group only one person was a true participant. The others were actors with a script. Most of the actors were instructed to give the wrong answer. Strangely, the one true participant almost always agreed with the majority, even though they knew they were giving the wrong answer.

The results of this study are important when we study social interactions among individuals in groups. This study is a famous example of the temptation many of us experience to conform to a standard during group situations and it showed that people often care more about being the same as others than they do about being right. It is still recognized as one of the most influential psychological experiments for understanding human behavior.

3. Bobo Doll Experiment

Study conducted by: dr. alburt bandura.

Study Conducted between 1961-1963 at Stanford University

In his groundbreaking study he separated participants into three groups:

• one was exposed to a video of an adult showing aggressive behavior towards a Bobo doll
• another was exposed to video of a passive adult playing with the Bobo doll
• the third formed a control group

Children watched their assigned video and then were sent to a room with the same doll they had seen in the video (with the exception of those in the control group). What the researcher found was that children exposed to the aggressive model were more likely to exhibit aggressive behavior towards the doll themselves. The other groups showed little imitative aggressive behavior. For those children exposed to the aggressive model, the number of derivative physical aggressions shown by the boys was 38.2 and 12.7 for the girls.

The study also showed that boys exhibited more aggression when exposed to aggressive male models than boys exposed to aggressive female models. When exposed to aggressive male models, the number of aggressive instances exhibited by boys averaged 104. This is compared to 48.4 aggressive instances exhibited by boys who were exposed to aggressive female models.

While the results for the girls show similar findings, the results were less drastic. When exposed to aggressive female models, the number of aggressive instances exhibited by girls averaged 57.7. This is compared to 36.3 aggressive instances exhibited by girls who were exposed to aggressive male models. The results concerning gender differences strongly supported Bandura’s secondary prediction that children will be more strongly influenced by same-sex models. The Bobo Doll Experiment showed a groundbreaking way to study human behavior and it’s influences.

4. Car Crash Experiment

Study conducted by: elizabeth loftus and john palmer.

Study Conducted in 1974 at The University of California in Irvine

The participants watched slides of a car accident and were asked to describe what had happened as if they were eyewitnesses to the scene. The participants were put into two groups and each group was questioned using different wording such as “how fast was the car driving at the time of impact?” versus “how fast was the car going when it smashed into the other car?” The experimenters found that the use of different verbs affected the participants’ memories of the accident, showing that memory can be easily distorted.

This research suggests that memory can be easily manipulated by questioning technique. This means that information gathered after the event can merge with original memory causing incorrect recall or reconstructive memory. The addition of false details to a memory of an event is now referred to as confabulation. This concept has very important implications for the questions used in police interviews of eyewitnesses.

5. Cognitive Dissonance Experiment

Study conducted by: leon festinger and james carlsmith.

Study Conducted in 1957 at Stanford University

Experiment Details: The concept of cognitive dissonance refers to a situation involving conflicting:

This conflict produces an inherent feeling of discomfort leading to a change in one of the attitudes, beliefs or behaviors to minimize or eliminate the discomfort and restore balance.

Cognitive dissonance was first investigated by Leon Festinger, after an observational study of a cult that believed that the earth was going to be destroyed by a flood. Out of this study was born an intriguing experiment conducted by Festinger and Carlsmith where participants were asked to perform a series of dull tasks (such as turning pegs in a peg board for an hour). Participant’s initial attitudes toward this task were highly negative.

They were then paid either $1 or $20 to tell a participant waiting in the lobby that the tasks were really interesting. Almost all of the participants agreed to walk into the waiting room and persuade the next participant that the boring experiment would be fun. When the participants were later asked to evaluate the experiment, the participants who were paid only $1 rated the tedious task as more fun and enjoyable than the participants who were paid $20 to lie.

Being paid only $1 is not sufficient incentive for lying and so those who were paid $1 experienced dissonance. They could only overcome that cognitive dissonance by coming to believe that the tasks really were interesting and enjoyable. Being paid $20 provides a reason for turning pegs and there is therefore no dissonance.

6. Fantz’s Looking Chamber

Study conducted by: robert l. fantz.

Study Conducted in 1961 at the University of Illinois

Experiment Details: The study conducted by Robert L. Fantz is among the simplest, yet most important in the field of infant development and vision. In 1961, when this experiment was conducted, there very few ways to study what was going on in the mind of an infant. Fantz realized that the best way was to simply watch the actions and reactions of infants. He understood the fundamental factor that if there is something of interest near humans, they generally look at it.

To test this concept, Fantz set up a display board with two pictures attached. On one was a bulls-eye. On the other was the sketch of a human face. This board was hung in a chamber where a baby could lie safely underneath and see both images. Then, from behind the board, invisible to the baby, he peeked through a hole to watch what the baby looked at. This study showed that a two-month old baby looked twice as much at the human face as it did at the bulls-eye. This suggests that human babies have some powers of pattern and form selection. Before this experiment it was thought that babies looked out onto a chaotic world of which they could make little sense.

7. Hawthorne Effect

Study conducted by: henry a. landsberger.

Study Conducted in 1955 at Hawthorne Works in Chicago, Illinois

Landsberger performed the study by analyzing data from experiments conducted between 1924 and 1932, by Elton Mayo, at the Hawthorne Works near Chicago. The company had commissioned studies to evaluate whether the level of light in a building changed the productivity of the workers. What Mayo found was that the level of light made no difference in productivity. The workers increased their output whenever the amount of light was switched from a low level to a high level, or vice versa.

The researchers noticed a tendency that the workers’ level of efficiency increased when any variable was manipulated. The study showed that the output changed simply because the workers were aware that they were under observation. The conclusion was that the workers felt important because they were pleased to be singled out. They increased productivity as a result. Being singled out was the factor dictating increased productivity, not the changing lighting levels, or any of the other factors that they experimented upon.

The Hawthorne Effect has become one of the hardest inbuilt biases to eliminate or factor into the design of any experiment in psychology and beyond.

8. Kitty Genovese Case

Study conducted by: new york police force.

Study Conducted in 1964 in New York City

Experiment Details: The murder case of Kitty Genovese was never intended to be a psychological experiment, however it ended up having serious implications for the field.

According to a New York Times article, almost 40 neighbors witnessed Kitty Genovese being savagely attacked and murdered in Queens, New York in 1964. Not one neighbor called the police for help. Some reports state that the attacker briefly left the scene and later returned to “finish off” his victim. It was later uncovered that many of these facts were exaggerated. (There were more likely only a dozen witnesses and records show that some calls to police were made).

What this case later become famous for is the “Bystander Effect,” which states that the more bystanders that are present in a social situation, the less likely it is that anyone will step in and help. This effect has led to changes in medicine, psychology and many other areas. One famous example is the way CPR is taught to new learners. All students in CPR courses learn that they must assign one bystander the job of alerting authorities which minimizes the chances of no one calling for assistance.

9. Learned Helplessness Experiment

Study conducted by: martin seligman.

Study Conducted in 1967 at the University of Pennsylvania

Seligman’s experiment involved the ringing of a bell and then the administration of a light shock to a dog. After a number of pairings, the dog reacted to the shock even before it happened. As soon as the dog heard the bell, he reacted as though he’d already been shocked.

During the course of this study something unexpected happened. Each dog was placed in a large crate that was divided down the middle with a low fence. The dog could see and jump over the fence easily. The floor on one side of the fence was electrified, but not on the other side of the fence. Seligman placed each dog on the electrified side and administered a light shock. He expected the dog to jump to the non-shocking side of the fence. In an unexpected turn, the dogs simply laid down.

The hypothesis was that as the dogs learned from the first part of the experiment that there was nothing they could do to avoid the shocks, they gave up in the second part of the experiment. To prove this hypothesis the experimenters brought in a new set of animals and found that dogs with no history in the experiment would jump over the fence.

This condition was described as learned helplessness. A human or animal does not attempt to get out of a negative situation because the past has taught them that they are helpless.

10. Little Albert Experiment

Study conducted by: john b. watson and rosalie rayner.

Study Conducted in 1920 at Johns Hopkins University

The experiment began by placing a white rat in front of the infant, who initially had no fear of the animal. Watson then produced a loud sound by striking a steel bar with a hammer every time little Albert was presented with the rat. After several pairings (the noise and the presentation of the white rat), the boy began to cry and exhibit signs of fear every time the rat appeared in the room. Watson also created similar conditioned reflexes with other common animals and objects (rabbits, Santa beard, etc.) until Albert feared them all.

This study proved that classical conditioning works on humans. One of its most important implications is that adult fears are often connected to early childhood experiences.

11. Magical Number Seven

Study conducted by: george a. miller.

Study Conducted in 1956 at Princeton University

Experiment Details:   Frequently referred to as “ Miller’s Law,” the Magical Number Seven experiment purports that the number of objects an average human can hold in working memory is 7 ± 2. This means that the human memory capacity typically includes strings of words or concepts ranging from 5-9. This information on the limits to the capacity for processing information became one of the most highly cited papers in psychology.

The Magical Number Seven Experiment was published in 1956 by cognitive psychologist George A. Miller of Princeton University’s Department of Psychology in Psychological Review .  In the article, Miller discussed a concurrence between the limits of one-dimensional absolute judgment and the limits of short-term memory.

In a one-dimensional absolute-judgment task, a person is presented with a number of stimuli that vary on one dimension (such as 10 different tones varying only in pitch). The person responds to each stimulus with a corresponding response (learned before).

Performance is almost perfect up to five or six different stimuli but declines as the number of different stimuli is increased. This means that a human’s maximum performance on one-dimensional absolute judgment can be described as an information store with the maximum capacity of approximately 2 to 3 bits of information There is the ability to distinguish between four and eight alternatives.

12. Pavlov’s Dog Experiment

Study conducted by: ivan pavlov.

Study Conducted in the 1890s at the Military Medical Academy in St. Petersburg, Russia

Pavlov began with the simple idea that there are some things that a dog does not need to learn. He observed that dogs do not learn to salivate when they see food. This reflex is “hard wired” into the dog. This is an unconditioned response (a stimulus-response connection that required no learning).

Pavlov outlined that there are unconditioned responses in the animal by presenting a dog with a bowl of food and then measuring its salivary secretions. In the experiment, Pavlov used a bell as his neutral stimulus. Whenever he gave food to his dogs, he also rang a bell. After a number of repeats of this procedure, he tried the bell on its own. What he found was that the bell on its own now caused an increase in salivation. The dog had learned to associate the bell and the food. This learning created a new behavior. The dog salivated when he heard the bell. Because this response was learned (or conditioned), it is called a conditioned response. The neutral stimulus has become a conditioned stimulus.

This theory came to be known as classical conditioning.

13. Robbers Cave Experiment

Study conducted by: muzafer and carolyn sherif.

Study Conducted in 1954 at the University of Oklahoma

Experiment Details: This experiment, which studied group conflict, is considered by most to be outside the lines of what is considered ethically sound.

In 1954 researchers at the University of Oklahoma assigned 22 eleven- and twelve-year-old boys from similar backgrounds into two groups. The two groups were taken to separate areas of a summer camp facility where they were able to bond as social units. The groups were housed in separate cabins and neither group knew of the other’s existence for an entire week. The boys bonded with their cabin mates during that time. Once the two groups were allowed to have contact, they showed definite signs of prejudice and hostility toward each other even though they had only been given a very short time to develop their social group. To increase the conflict between the groups, the experimenters had them compete against each other in a series of activities. This created even more hostility and eventually the groups refused to eat in the same room. The final phase of the experiment involved turning the rival groups into friends. The fun activities the experimenters had planned like shooting firecrackers and watching movies did not initially work, so they created teamwork exercises where the two groups were forced to collaborate. At the end of the experiment, the boys decided to ride the same bus home, demonstrating that conflict can be resolved and prejudice overcome through cooperation.

Many critics have compared this study to Golding’s Lord of the Flies novel as a classic example of prejudice and conflict resolution.

14. Ross’ False Consensus Effect Study

Study conducted by: lee ross.

Study Conducted in 1977 at Stanford University

Experiment Details: In 1977, a social psychology professor at Stanford University named Lee Ross conducted an experiment that, in lay terms, focuses on how people can incorrectly conclude that others think the same way they do, or form a “false consensus” about the beliefs and preferences of others. Ross conducted the study in order to outline how the “false consensus effect” functions in humans.

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In the first part of the study, participants were asked to read about situations in which a conflict occurred and then were told two alternative ways of responding to the situation. They were asked to do three things:

• Guess which option other people would choose
• Say which option they themselves would choose
• Describe the attributes of the person who would likely choose each of the two options

What the study showed was that most of the subjects believed that other people would do the same as them, regardless of which of the two responses they actually chose themselves. This phenomenon is referred to as the false consensus effect, where an individual thinks that other people think the same way they do when they may not. The second observation coming from this important study is that when participants were asked to describe the attributes of the people who will likely make the choice opposite of their own, they made bold and sometimes negative predictions about the personalities of those who did not share their choice.

15. The Schachter and Singer Experiment on Emotion

Study conducted by: stanley schachter and jerome e. singer.

Study Conducted in 1962 at Columbia University

Experiment Details: In 1962 Schachter and Singer conducted a ground breaking experiment to prove their theory of emotion.

In the study, a group of 184 male participants were injected with epinephrine, a hormone that induces arousal including increased heartbeat, trembling, and rapid breathing. The research participants were told that they were being injected with a new medication to test their eyesight. The first group of participants was informed the possible side effects that the injection might cause while the second group of participants were not. The participants were then placed in a room with someone they thought was another participant, but was actually a confederate in the experiment. The confederate acted in one of two ways: euphoric or angry. Participants who had not been informed about the effects of the injection were more likely to feel either happier or angrier than those who had been informed.

What Schachter and Singer were trying to understand was the ways in which cognition or thoughts influence human emotion. Their study illustrates the importance of how people interpret their physiological states, which form an important component of your emotions. Though their cognitive theory of emotional arousal dominated the field for two decades, it has been criticized for two main reasons: the size of the effect seen in the experiment was not that significant and other researchers had difficulties repeating the experiment.

16. Selective Attention / Invisible Gorilla Experiment

Study conducted by: daniel simons and christopher chabris.

Study Conducted in 1999 at Harvard University

Experiment Details: In 1999 Simons and Chabris conducted their famous awareness test at Harvard University.

Participants in the study were asked to watch a video and count how many passes occurred between basketball players on the white team. The video moves at a moderate pace and keeping track of the passes is a relatively easy task. What most people fail to notice amidst their counting is that in the middle of the test, a man in a gorilla suit walked onto the court and stood in the center before walking off-screen.

The study found that the majority of the subjects did not notice the gorilla at all, proving that humans often overestimate their ability to effectively multi-task. What the study set out to prove is that when people are asked to attend to one task, they focus so strongly on that element that they may miss other important details.

17. Stanford Prison Study

Study conducted by philip zimbardo.

Study Conducted in 1971 at Stanford University

The Stanford Prison Experiment was designed to study behavior of “normal” individuals when assigned a role of prisoner or guard. College students were recruited to participate. They were assigned roles of “guard” or “inmate.”  Zimbardo played the role of the warden. The basement of the psychology building was the set of the prison. Great care was taken to make it look and feel as realistic as possible.

The prison guards were told to run a prison for two weeks. They were told not to physically harm any of the inmates during the study. After a few days, the prison guards became very abusive verbally towards the inmates. Many of the prisoners became submissive to those in authority roles. The Stanford Prison Experiment inevitably had to be cancelled because some of the participants displayed troubling signs of breaking down mentally.

Although the experiment was conducted very unethically, many psychologists believe that the findings showed how much human behavior is situational. People will conform to certain roles if the conditions are right. The Stanford Prison Experiment remains one of the most famous psychology experiments of all time.

18. Stanley Milgram Experiment

Study conducted by stanley milgram.

Study Conducted in 1961 at Stanford University

Experiment Details: This 1961 study was conducted by Yale University psychologist Stanley Milgram. It was designed to measure people’s willingness to obey authority figures when instructed to perform acts that conflicted with their morals. The study was based on the premise that humans will inherently take direction from authority figures from very early in life.

Participants were told they were participating in a study on memory. They were asked to watch another person (an actor) do a memory test. They were instructed to press a button that gave an electric shock each time the person got a wrong answer. (The actor did not actually receive the shocks, but pretended they did).

Participants were told to play the role of “teacher” and administer electric shocks to “the learner,” every time they answered a question incorrectly. The experimenters asked the participants to keep increasing the shocks. Most of them obeyed even though the individual completing the memory test appeared to be in great pain. Despite these protests, many participants continued the experiment when the authority figure urged them to. They increased the voltage after each wrong answer until some eventually administered what would be lethal electric shocks.

This experiment showed that humans are conditioned to obey authority and will usually do so even if it goes against their natural morals or common sense.

19. Surrogate Mother Experiment

Study conducted by: harry harlow.

Study Conducted from 1957-1963 at the University of Wisconsin

Experiment Details: In a series of controversial experiments during the late 1950s and early 1960s, Harry Harlow studied the importance of a mother’s love for healthy childhood development.

In order to do this he separated infant rhesus monkeys from their mothers a few hours after birth and left them to be raised by two “surrogate mothers.” One of the surrogates was made of wire with an attached bottle for food. The other was made of soft terrycloth but lacked food. The researcher found that the baby monkeys spent much more time with the cloth mother than the wire mother, thereby proving that affection plays a greater role than sustenance when it comes to childhood development. They also found that the monkeys that spent more time cuddling the soft mother grew up to healthier.

This experiment showed that love, as demonstrated by physical body contact, is a more important aspect of the parent-child bond than the provision of basic needs. These findings also had implications in the attachment between fathers and their infants when the mother is the source of nourishment.

20. The Good Samaritan Experiment

Study conducted by: john darley and daniel batson.

Study Conducted in 1973 at The Princeton Theological Seminary (Researchers were from Princeton University)

Experiment Details: In 1973, an experiment was created by John Darley and Daniel Batson, to investigate the potential causes that underlie altruistic behavior. The researchers set out three hypotheses they wanted to test:

• People thinking about religion and higher principles would be no more inclined to show helping behavior than laymen.
• People in a rush would be much less likely to show helping behavior.
• People who are religious for personal gain would be less likely to help than people who are religious because they want to gain some spiritual and personal insights into the meaning of life.

Student participants were given some religious teaching and instruction. They were then were told to travel from one building to the next. Between the two buildings was a man lying injured and appearing to be in dire need of assistance. The first variable being tested was the degree of urgency impressed upon the subjects, with some being told not to rush and others being informed that speed was of the essence.

The results of the experiment were intriguing, with the haste of the subject proving to be the overriding factor. When the subject was in no hurry, nearly two-thirds of people stopped to lend assistance. When the subject was in a rush, this dropped to one in ten.

People who were on the way to deliver a speech about helping others were nearly twice as likely to help as those delivering other sermons,. This showed that the thoughts of the individual were a factor in determining helping behavior. Religious beliefs did not appear to make much difference on the results. Being religious for personal gain, or as part of a spiritual quest, did not appear to make much of an impact on the amount of helping behavior shown.

21. The Halo Effect Experiment

Study conducted by: richard e. nisbett and timothy decamp wilson.

Study Conducted in 1977 at the University of Michigan

Experiment Details: The Halo Effect states that people generally assume that people who are physically attractive are more likely to:

• be intelligent
• be friendly
• display good judgment

To prove their theory, Nisbett and DeCamp Wilson created a study to prove that people have little awareness of the nature of the Halo Effect. They’re not aware that it influences:

• their personal judgments
• the production of a more complex social behavior

In the experiment, college students were the research participants. They were asked to evaluate a psychology instructor as they view him in a videotaped interview. The students were randomly assigned to one of two groups. Each group was shown one of two different interviews with the same instructor. The instructor is a native French-speaking Belgian who spoke English with a noticeable accent. In the first video, the instructor presented himself as someone:

• respectful of his students’ intelligence and motives
• flexible in his approach to teaching
• enthusiastic about his subject matter

In the second interview, he presented himself as much more unlikable. He was cold and distrustful toward the students and was quite rigid in his teaching style.

After watching the videos, the subjects were asked to rate the lecturer on:

• physical appearance

His mannerisms and accent were kept the same in both versions of videos. The subjects were asked to rate the professor on an 8-point scale ranging from “like extremely” to “dislike extremely.” Subjects were also told that the researchers were interested in knowing “how much their liking for the teacher influenced the ratings they just made.” Other subjects were asked to identify how much the characteristics they just rated influenced their liking of the teacher.

After responding to the questionnaire, the respondents were puzzled about their reactions to the videotapes and to the questionnaire items. The students had no idea why they gave one lecturer higher ratings. Most said that how much they liked the lecturer had not affected their evaluation of his individual characteristics at all.

The interesting thing about this study is that people can understand the phenomenon, but they are unaware when it is occurring. Without realizing it, humans make judgments. Even when it is pointed out, they may still deny that it is a product of the halo effect phenomenon.

22. The Marshmallow Test

Study conducted by: walter mischel.

Study Conducted in 1972 at Stanford University

In his 1972 Marshmallow Experiment, children ages four to six were taken into a room where a marshmallow was placed in front of them on a table. Before leaving each of the children alone in the room, the experimenter informed them that they would receive a second marshmallow if the first one was still on the table after they returned in 15 minutes. The examiner recorded how long each child resisted eating the marshmallow and noted whether it correlated with the child’s success in adulthood. A small number of the 600 children ate the marshmallow immediately and one-third delayed gratification long enough to receive the second marshmallow.

In follow-up studies, Mischel found that those who deferred gratification were significantly more competent and received higher SAT scores than their peers. This characteristic likely remains with a person for life. While this study seems simplistic, the findings outline some of the foundational differences in individual traits that can predict success.

23. The Monster Study

Study conducted by: wendell johnson.

Study Conducted in 1939 at the University of Iowa

Experiment Details: The Monster Study received this negative title due to the unethical methods that were used to determine the effects of positive and negative speech therapy on children.

Wendell Johnson of the University of Iowa selected 22 orphaned children, some with stutters and some without. The children were in two groups. The group of children with stutters was placed in positive speech therapy, where they were praised for their fluency. The non-stutterers were placed in negative speech therapy, where they were disparaged for every mistake in grammar that they made.

As a result of the experiment, some of the children who received negative speech therapy suffered psychological effects and retained speech problems for the rest of their lives. They were examples of the significance of positive reinforcement in education.

The initial goal of the study was to investigate positive and negative speech therapy. However, the implication spanned much further into methods of teaching for young children.

24. Violinist at the Metro Experiment

Study conducted by: staff at the washington post.

Study Conducted in 2007 at a Washington D.C. Metro Train Station

During the study, pedestrians rushed by without realizing that the musician playing at the entrance to the metro stop was Grammy-winning musician, Joshua Bell. Two days before playing in the subway, he sold out at a theater in Boston where the seats average $100. He played one of the most intricate pieces ever written with a violin worth 3.5 million dollars. In the 45 minutes the musician played his violin, only 6 people stopped and stayed for a while. Around 20 gave him money, but continued to walk their normal pace. He collected $32.

The study and the subsequent article organized by the Washington Post was part of a social experiment looking at:

• the priorities of people

Gene Weingarten wrote about the social experiment: “In a banal setting at an inconvenient time, would beauty transcend?” Later he won a Pulitzer Prize for his story. Some of the questions the article addresses are:

• Do we perceive beauty?
• Do we stop to appreciate it?
• Do we recognize the talent in an unexpected context?

As it turns out, many of us are not nearly as perceptive to our environment as we might like to think.

25. Visual Cliff Experiment

Study conducted by: eleanor gibson and richard walk.

Study Conducted in 1959 at Cornell University

Experiment Details: In 1959, psychologists Eleanor Gibson and Richard Walk set out to study depth perception in infants. They wanted to know if depth perception is a learned behavior or if it is something that we are born with. To study this, Gibson and Walk conducted the visual cliff experiment.

They studied 36 infants between the ages of six and 14 months, all of whom could crawl. The infants were placed one at a time on a visual cliff. A visual cliff was created using a large glass table that was raised about a foot off the floor. Half of the glass table had a checker pattern underneath in order to create the appearance of a ‘shallow side.’

In order to create a ‘deep side,’ a checker pattern was created on the floor; this side is the visual cliff. The placement of the checker pattern on the floor creates the illusion of a sudden drop-off. Researchers placed a foot-wide centerboard between the shallow side and the deep side. Gibson and Walk found the following:

• Nine of the infants did not move off the centerboard.
• All of the 27 infants who did move crossed into the shallow side when their mothers called them from the shallow side.
• Three of the infants crawled off the visual cliff toward their mother when called from the deep side.
• When called from the deep side, the remaining 24 children either crawled to the shallow side or cried because they could not cross the visual cliff and make it to their mother.

What this study helped demonstrate is that depth perception is likely an inborn train in humans.

Among these experiments and psychological tests, we see boundaries pushed and theories taking on a life of their own. It is through the endless stream of psychological experimentation that we can see simple hypotheses become guiding theories for those in this field. The greater field of psychology became a formal field of experimental study in 1879, when Wilhelm Wundt established the first laboratory dedicated solely to psychological research in Leipzig, Germany. Wundt was the first person to refer to himself as a psychologist. Since 1879, psychology has grown into a massive collection of:

• methods of practice

It’s also a specialty area in the field of healthcare. None of this would have been possible without these and many other important psychological experiments that have stood the test of time.

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About the Author

After earning a Bachelor of Arts in Psychology from Rutgers University and then a Master of Science in Clinical and Forensic Psychology from Drexel University, Kristen began a career as a therapist at two prisons in Philadelphia. At the same time she volunteered as a rape crisis counselor, also in Philadelphia. After a few years in the field she accepted a teaching position at a local college where she currently teaches online psychology courses. Kristen began writing in college and still enjoys her work as a writer, editor, professor and mother.

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The 11 Most Influential Psychological Experiments in History

The history of psychology is marked by groundbreaking experiments that transformed our understanding of the human mind. These 11 Most Influential Psychological Experiments in History stand out as pivotal, offering profound insights into behaviour, cognition, and the complexities of human nature.

In this PsychologyOrg article, we’ll explain these key experiments, exploring their impact on our understanding of human behaviour and the intricate workings of the mind.

Table of Contents

Experimental psychology.

Experimental psychology is a branch of psychology that uses scientific methods to study human behaviour and mental processes. Researchers in this field design experiments to test hypotheses about topics such as perception, learning, memory, emotion, and motivation.

They use a variety of techniques to measure and analyze behaviour and mental processes, including behavioural observations, self-report measures, physiological recordings, and computer simulations. The findings of experimental psychology studies can have important implications for a wide range of fields, including education, healthcare, and public policy.

Experimental Psychology, Psychologists have long tried to gain insight into how we perceive the world, to understand what motivates our behavior. They have made great strides in lifting that veil of mystery. In addition to providing us with food for stimulating party conversations, some of the most famous psychological experiments of the last century reveal surprising and universal truths about nature.

Throughout the history of psychology, revolutionary experiments have reshaped our comprehension of the human mind. These 11 experiments are pivotal, providing deep insights into human behaviour, cognition, and the intricate facets of human nature.

1. Kohler and the Chimpanzee experiment

Wolfgang Kohler studied the insight process by observing the behaviour of chimpanzees in a problem situation. In the experimental situation, the animals were placed in a cage outside of which food, for example, a banana, was stored. There were other objects in the cage, such as sticks or boxes. The animals participating in the experiment were hungry, so they needed to get to the food. At first, the chimpanzee used sticks mainly for playful activities; but suddenly, in the mind of the hungry chimpanzee, a relationship between sticks and food developed.

The cane, from an object to play with, became an instrument through which it was possible to reach the banana placed outside the cage. There has been a restructuring of the perceptual field: Kohler stressed that the appearance of the new behaviour was not the result of random attempts according to a process of trial and error. It is one of the first experiments on the intelligence of chimpanzees.

2. Harlow’s experiment on attachment with monkeys

In a scientific paper (1959), Harry F. Harlow described how he had separated baby rhesus monkeys from their mothers at birth, and raised them with the help of “puppet mothers”: in a series of experiments he compared the behavior of monkeys in two situations:

Little monkeys with a puppet mother without a bottle, but covered in a soft, fluffy, and furry fabric. Little monkeys with a “puppet” mother that supplied food, but was covered in wire. The little monkeys showed a clear preference for the “furry” mother, spending an average of fifteen hours a day attached to her, even though they were exclusively fed by the “suckling” puppet mother. conclusions of the Harlow experiment: all the experiments showed that the pleasure of contact elicited attachment behaviours, but the food did not.

3. The Strange Situation by Mary Ainsworth

Building on Bowlby’s attachment theory, Mary Ainsworth and colleagues (1978) have developed an experimental method called the Strange Situation, to assess individual differences in attachment security. The Strange Situation includes a series of short laboratory episodes in a comfortable environment and the child’s behaviors are observed.

Ainsworth and colleagues have paid special attention to the child’s behaviour at the time of reunion with the caregiver after a brief separation, thus identifying three different attachment patterns or styles, so called from that moment on. kinds of attachment according to Mary Ainsworth:

Secure attachment (63% of the dyads examined) Anxious-resistant or ambivalent (16%) Avoidant (21%) The Strange Situation by Mary Ainsworth

In a famous 1971 experiment, known as the Stanford Prison, Zimbardo and a team of collaborators reproduced a prison in the garages of Stanford University to study the behaviour of subjects in a context of very particular and complex dynamics. Let’s see how it went and the thoughts on the Stanford prison experiment. The participants (24 students) were randomly divided into two groups:

“ Prisoners “. The latter were locked up in three cells in the basement of a University building for six days; they were required to wear a white robe with a paper over it and a chain on the right ankle. “ Guards “. The students who had the role of prison guards had to watch the basement, choose the most appropriate methods to maintain order, and make the “prisoners” perform various tasks; they were asked to wear dark glasses and uniforms, and never to be violent towards the participants of the opposite role. However, the situation deteriorated dramatically: the fake police officers very soon began to seriously mistreat and humiliate the “detainees”, so it was decided to discontinue the experiment.

4. Jane Elliot’s Blue Eyes Experiment

On April 5, 1968, in a small school in Riceville, Iowa, Professor Jane Elliot decided to give a practical lesson on racism to 28 children of about eight years of age through the blue eyes brown eyes experiment.

“Children with brown eyes are the best,” the instructor began. “They are more beautiful and intelligent.” She wrote the word “melanin” on the board and explained that it was a substance that made people intelligent. Dark-eyed children have more, so they are more intelligent, while blue-eyed children “go hand in hand.”

In a very short time, the brown-eyed children began to treat their blue-eyed classmates with superiority, who in turn lost their self-confidence. A very good girl started making mistakes during arithmetic class, and at recess, she was approached by three little friends with brown eyes “You have to apologize because you get in their way and because we are the best,” said one of them. The girl hastened to apologize. This is one of the psychosocial experiments demonstrating how beliefs and prejudices play a role.

5. The Bobo de Bbandura doll

Albert Bandura gained great fame for the Bobo doll experiment on child imitation aggression, where:

A group of children took as an example, by visual capacity, the adults in a room, without their behaviour being commented on, hit the Bobo doll. Other contemporaries, on the other hand, saw adults sitting, always in absolute silence, next to Bobo.

Finally, all these children were brought to a room full of toys, including a doll like Bobo. Of the 10 children who hit the doll, 8 were those who had seen it done before by an adult. This explains how if a model that we follow performs a certain action, we are tempted to imitate it and this happens especially in children who still do not have the experience to understand for themselves if that behaviour is correct or not.

6. Milgram’s experiment

The Milgram experiment was first carried out in 1961 by psychologist Stanley Milgram, as an investigation into the degree of our deference to authority. A subject is invited to give an electric shock to an individual playing the role of the student, positioned behind a screen when he does not answer a question correctly. An authorized person then tells the subject to gradually increase the intensity of the shock until the student screams in pain and begs to stop.

No justification is given, except for the fact that the authorized person tells the subject to obey. In reality, it was staged: there was absolutely no electric shock given, but in the experiment two-thirds of the subjects were influenced by what they thought was a 450-volt shock, simply because a person in authority told them they would not be responsible for it. nothing.

7. little Albert

We see little Albert’s experiment on unconditioned stimulus, which must be the most famous psychological study. John Watson and Rosalie Raynor showed a white laboratory rat to a nine-month-old boy, little Albert. At first, the boy showed no fear, but then Watson jumped up from behind and made him flinch with a sudden noise by hitting a metal bar with a hammer. Of course, the noise frightened little Albert, who began to cry.

Every time the rat was brought out, Watson and Raynor would rattle the bar with their hammer to scare the poor boy away. Soon the mere sight of the rat was enough to reduce little Albert to a trembling bundle of nerves: he had learned to fear the sight of a rat, and soon afterwards began to fear a series of similar objects shown to him.

8. Pavlov’s dog

Ivan Pavlov’s sheepdog became famous for his experiments that led him to discover what we call “classical conditioning” or “Pavlovian reflex” and is still a very famous psychological experiment today. Hardly any other psychological experiment is cited so often and with such gusto as Pavlov’s theory expounded in 1905: the Russian physiologist had been impressed by the fact that his dogs did not begin to drool at the sight of food, but rather when they heard it. to the laboratory employees who took it away.

He researched it and ordered a buzzer to ring every time it was mealtime. Very soon the sound of the doorbell was enough for the dogs to start drooling: they had connected the signal to the arrival of food.

9. Asch’s experiment

It is about a social psychology experiment carried out in 1951 by the Polish psychologist Solomon Asch on the influence of the majority and social conformity.

The experiment is based on the idea that being part of a group is a sufficient condition to change a person’s actions, judgments, and visual perceptions. The very simple experiment consisted of asking the subjects involved to associate line 1 drawn on a white sheet with the corresponding one, choosing between three different lines A, B, and C present on another sheet. Only one was identical to the other, while the other two were longer or shorter.

The experimentation was carried out in three phases. As soon as one of the subjects, Asch’s accomplice gave a wrong answer associating line 1 with the wrong one, the other members of the group also made the same mistake, even though the correct answer was more than obvious. The participants questioned the reason for this choice and responded that aware of the correct answer, they had decided to conform to the group, adapting to those who had preceded them.

psychotherapy definition types and techniques | Psychotherapy vs therapy Psychologyorg.com

10. Rosenbaum’s experiment

Among the most interesting investigations in this field, an experiment carried out by David Rosenhan (1923) to document the low validity of psychiatric diagnoses stands out. Rosenhan admitted eight assistants to various psychiatric hospitals claiming psychotic symptoms, but once they entered the hospital they behaved as usual.

Despite this, they were held on average for 19 days, with all but one being diagnosed as “psychotic”. One of the reasons why the staff is not aware of the “normality” of the subjects, is, according to Rosenhan, the very little contact between the staff and the patients.

11. Bystander Effect (1968)

The Bystander Effect studied in 1968 after the tragic case of Kitty Genovese, explores how individuals are less likely to intervene in emergencies when others are present. The original research by John Darley and Bibb Latané involved staged scenarios where participants believed they were part of a discussion via intercom.

In the experiment, participants were led to believe they were communicating with others about personal problems. Unknown to them, the discussions were staged, and at a certain point, a participant (confederate) pretended to have a seizure or needed help.

The results were startling. When participants believed they were the sole witness to the emergency, they responded quickly and sought help. However, when they thought others were also present (but were confederates instructed to not intervene), the likelihood of any individual offering help significantly decreased. This phenomenon became known as the Bystander Effect.

The diffusion of responsibility, where individuals assume others will take action, contributes to this effect. The presence of others creates a diffusion of responsibility among bystanders, leading to a decreased likelihood of any single individual taking action.

This experiment highlighted the social and psychological factors influencing intervention during emergencies and emphasized the importance of understanding bystander behaviour in critical situations.

The journey through the “11 Most Influential Psychological Experiments in History” illuminates the profound impact these studies have had on our understanding of human behaviour, cognition, and social dynamics.

Each experiment stands as a testament to the dedication of pioneering psychologists who dared to delve into the complexities of the human mind. From Milgram’s obedience studies to Zimbardo’s Stanford Prison Experiment, these trials have shaped not only the field of psychology but also our societal perceptions and ethical considerations in research.

They serve as timeless benchmarks, reminding us of the ethical responsibilities and the far-reaching implications of delving into the human psyche. The enduring legacy of these experiments lies not only in their scientific contributions but also in the ethical reflections they provoke, urging us to navigate the boundaries of knowledge with caution, empathy, and an unwavering commitment to understanding the intricacies of our humanity.

What is the most famous experiment in the history of psychology?

One of the most famous experiments is the Milgram Experiment, conducted by Stanley Milgram in the 1960s. It investigated obedience to authority figures and remains influential in understanding human behaviour.

Who wrote the 25 most influential psychological experiments in history?

The book “The 25 Most Influential Psychological Experiments in History” was written by Michael Shermer, a science writer and historian of science.

What is the history of experimental psychology?

Experimental psychology traces back to Wilhelm Wundt, often considered the father of experimental psychology. He established the first psychology laboratory in 1879 at the University of Leipzig, marking the formal beginning of experimental psychology as a distinct field.

What was the psychological experiment in the 1960s?

Many significant psychological experiments were conducted in the 1960s. One notable example is the Stanford Prison Experiment led by Philip Zimbardo, which examined the effects of situational roles on behaviour.

Who was the first experimental psychologist?

Wilhelm Wundt is often regarded as the first experimental psychologist due to his establishment of the first psychology laboratory and his emphasis on empirical research methods in psychology.

If you want to read more articles similar to  The 11 Most Influential Psychological Experiments in History , we recommend that you enter our  Psychology  category.

I'm Waqar, a passionate psychologist and dedicated content writer. With a deep interest in understanding human behavior, I aim to share insights and knowledge in the field of psychology through this blog. Feel free to reach out for collaborations, queries, or discussions. Let's dig into the fascinating world of psychology together!

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15 Famous Experiments and Case Studies in Psychology

Chris Drew (PhD)

Dr. Chris Drew is the founder of the Helpful Professor. He holds a PhD in education and has published over 20 articles in scholarly journals. He is the former editor of the Journal of Learning Development in Higher Education. [Image Descriptor: Photo of Chris]

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Psychology has seen thousands upon thousands of research studies over the years. Most of these studies have helped shape our current understanding of human thoughts, behavior, and feelings.

The psychology case studies in this list are considered classic examples of psychological case studies and experiments, which are still being taught in introductory psychology courses up to this day.

Some studies, however, were downright shocking and controversial that you’d probably wonder why such studies were conducted back in the day. Imagine participating in an experiment for a small reward or extra class credit, only to be left scarred for life. These kinds of studies, however, paved the way for a more ethical approach to studying psychology and implementation of research standards such as the use of debriefing in psychology research .

Case Study vs. Experiment

Before we dive into the list of the most famous studies in psychology, let us first review the difference between case studies and experiments.

• It is an in-depth study and analysis of an individual, group, community, or phenomenon. The results of a case study cannot be applied to the whole population, but they can provide insights for further studies.
• It often uses qualitative research methods such as observations, surveys, and interviews.
• It is often conducted in real-life settings rather than in controlled environments.
• An experiment is a type of study done on a sample or group of random participants, the results of which can be generalized to the whole population.
• It often uses quantitative research methods that rely on numbers and statistics.
• It is conducted in controlled environments, wherein some things or situations are manipulated.

See Also: Experimental vs Observational Studies

Famous Experiments in Psychology

1. the marshmallow experiment.

Psychologist Walter Mischel conducted the marshmallow experiment at Stanford University in the 1960s to early 1970s. It was a simple test that aimed to define the connection between delayed gratification and success in life.

The instructions were fairly straightforward: children ages 4-6 were presented a piece of marshmallow on a table and they were told that they would receive a second piece if they could wait for 15 minutes without eating the first marshmallow.

About one-third of the 600 participants succeeded in delaying gratification to receive the second marshmallow. Mischel and his team followed up on these participants in the 1990s, learning that those who had the willpower to wait for a larger reward experienced more success in life in terms of SAT scores and other metrics.

This case study also supported self-control theory , a theory in criminology that holds that people with greater self-control are less likely to end up in trouble with the law!

The classic marshmallow experiment, however, was debunked in a 2018 replication study done by Tyler Watts and colleagues.

This more recent experiment had a larger group of participants (900) and a better representation of the general population when it comes to race and ethnicity. In this study, the researchers found out that the ability to wait for a second marshmallow does not depend on willpower alone but more so on the economic background and social status of the participants.

2. The Bystander Effect

In 1694, Kitty Genovese was murdered in the neighborhood of Kew Gardens, New York. It was told that there were up to 38 witnesses and onlookers in the vicinity of the crime scene, but nobody did anything to stop the murder or call for help.

Such tragedy was the catalyst that inspired social psychologists Bibb Latane and John Darley to formulate the phenomenon called bystander effect or bystander apathy .

Subsequent investigations showed that this story was exaggerated and inaccurate, as there were actually only about a dozen witnesses, at least two of whom called the police. But the case of Kitty Genovese led to various studies that aim to shed light on the bystander phenomenon.

Latane and Darley tested bystander intervention in an experimental study . Participants were asked to answer a questionnaire inside a room, and they would either be alone or with two other participants (who were actually actors or confederates in the study). Smoke would then come out from under the door. The reaction time of participants was tested — how long would it take them to report the smoke to the authorities or the experimenters?

The results showed that participants who were alone in the room reported the smoke faster than participants who were with two passive others. The study suggests that the more onlookers are present in an emergency situation, the less likely someone would step up to help, a social phenomenon now popularly called the bystander effect.

3. Asch Conformity Study

Have you ever made a decision against your better judgment just to fit in with your friends or family? The Asch Conformity Studies will help you understand this kind of situation better.

In this experiment, a group of participants were shown three numbered lines of different lengths and asked to identify the longest of them all. However, only one true participant was present in every group and the rest were actors, most of whom told the wrong answer.

Results showed that the participants went for the wrong answer, even though they knew which line was the longest one in the first place. When the participants were asked why they identified the wrong one, they said that they didn’t want to be branded as strange or peculiar.

This study goes to show that there are situations in life when people prefer fitting in than being right. It also tells that there is power in numbers — a group’s decision can overwhelm a person and make them doubt their judgment.

4. The Bobo Doll Experiment

The Bobo Doll Experiment was conducted by Dr. Albert Bandura, the proponent of social learning theory .

Back in the 1960s, the Nature vs. Nurture debate was a popular topic among psychologists. Bandura contributed to this discussion by proposing that human behavior is mostly influenced by environmental rather than genetic factors.

In the Bobo Doll Experiment, children were divided into three groups: one group was shown a video in which an adult acted aggressively toward the Bobo Doll, the second group was shown a video in which an adult play with the Bobo Doll, and the third group served as the control group where no video was shown.

The children were then led to a room with different kinds of toys, including the Bobo Doll they’ve seen in the video. Results showed that children tend to imitate the adults in the video. Those who were presented the aggressive model acted aggressively toward the Bobo Doll while those who were presented the passive model showed less aggression.

While the Bobo Doll Experiment can no longer be replicated because of ethical concerns, it has laid out the foundations of social learning theory and helped us understand the degree of influence adult behavior has on children.

5. Blue Eye / Brown Eye Experiment

Following the assassination of Martin Luther King Jr. in 1968, third-grade teacher Jane Elliott conducted an experiment in her class. Although not a formal experiment in controlled settings, A Class Divided is a good example of a social experiment to help children understand the concept of racism and discrimination.

The class was divided into two groups: blue-eyed children and brown-eyed children. For one day, Elliott gave preferential treatment to her blue-eyed students, giving them more attention and pampering them with rewards. The next day, it was the brown-eyed students’ turn to receive extra favors and privileges.

As a result, whichever group of students was given preferential treatment performed exceptionally well in class, had higher quiz scores, and recited more frequently; students who were discriminated against felt humiliated, answered poorly in tests, and became uncertain with their answers in class.

This study is now widely taught in sociocultural psychology classes.

6. Stanford Prison Experiment

One of the most controversial and widely-cited studies in psychology is the Stanford Prison Experiment , conducted by Philip Zimbardo at the basement of the Stanford psychology building in 1971. The hypothesis was that abusive behavior in prisons is influenced by the personality traits of the prisoners and prison guards.

The participants in the experiment were college students who were randomly assigned as either a prisoner or a prison guard. The prison guards were then told to run the simulated prison for two weeks. However, the experiment had to be stopped in just 6 days.

The prison guards abused their authority and harassed the prisoners through verbal and physical means. The prisoners, on the other hand, showed submissive behavior. Zimbardo decided to stop the experiment because the prisoners were showing signs of emotional and physical breakdown.

Although the experiment wasn’t completed, the results strongly showed that people can easily get into a social role when others expect them to, especially when it’s highly stereotyped .

7. The Halo Effect

Have you ever wondered why toothpastes and other dental products are endorsed in advertisements by celebrities more often than dentists? The Halo Effect is one of the reasons!

The Halo Effect shows how one favorable attribute of a person can gain them positive perceptions in other attributes. In the case of product advertisements, attractive celebrities are also perceived as intelligent and knowledgeable of a certain subject matter even though they’re not technically experts.

The Halo Effect originated in a classic study done by Edward Thorndike in the early 1900s. He asked military commanding officers to rate their subordinates based on different qualities, such as physical appearance, leadership, dependability, and intelligence.

The results showed that high ratings of a particular quality influences the ratings of other qualities, producing a halo effect of overall high ratings. The opposite also applied, which means that a negative rating in one quality also correlated to negative ratings in other qualities.

Experiments on the Halo Effect came in various formats as well, supporting Thorndike’s original theory. This phenomenon suggests that our perception of other people’s overall personality is hugely influenced by a quality that we focus on.

8. Cognitive Dissonance

There are experiences in our lives when our beliefs and behaviors do not align with each other and we try to justify them in our minds. This is cognitive dissonance , which was studied in an experiment by Leon Festinger and James Carlsmith back in 1959.

In this experiment, participants had to go through a series of boring and repetitive tasks, such as spending an hour turning pegs in a wooden knob. After completing the tasks, they were then paid either $1 or $20 to tell the next participants that the tasks were extremely fun and enjoyable. Afterwards, participants were asked to rate the experiment. Those who were given $1 rated the experiment as more interesting and fun than those who received $20.

The results showed that those who received a smaller incentive to lie experienced cognitive dissonance — $1 wasn’t enough incentive for that one hour of painstakingly boring activity, so the participants had to justify that they had fun anyway.

Famous Case Studies in Psychology

9. little albert.

In 1920, behaviourist theorists John Watson and Rosalie Rayner experimented on a 9-month-old baby to test the effects of classical conditioning in instilling fear in humans.

This was such a controversial study that it gained popularity in psychology textbooks and syllabi because it is a classic example of unethical research studies done in the name of science.

In one of the experiments, Little Albert was presented with a harmless stimulus or object, a white rat, which he wasn’t scared of at first. But every time Little Albert would see the white rat, the researchers would play a scary sound of hammer and steel. After about 6 pairings, Little Albert learned to fear the rat even without the scary sound.

Little Albert developed signs of fear to different objects presented to him through classical conditioning . He even generalized his fear to other stimuli not present in the course of the experiment.

10. Phineas Gage

Phineas Gage is such a celebrity in Psych 101 classes, even though the way he rose to popularity began with a tragic accident. He was a resident of Central Vermont and worked in the construction of a new railway line in the mid-1800s. One day, an explosive went off prematurely, sending a tamping iron straight into his face and through his brain.

Gage survived the accident, fortunately, something that is considered a feat even up to this day. He managed to find a job as a stagecoach after the accident. However, his family and friends reported that his personality changed so much that “he was no longer Gage” (Harlow, 1868).

New evidence on the case of Phineas Gage has since come to light, thanks to modern scientific studies and medical tests. However, there are still plenty of mysteries revolving around his brain damage and subsequent recovery.

11. Anna O.

Anna O., a social worker and feminist of German Jewish descent, was one of the first patients to receive psychoanalytic treatment.

Her real name was Bertha Pappenheim and she inspired much of Sigmund Freud’s works and books on psychoanalytic theory, although they hadn’t met in person. Their connection was through Joseph Breuer, Freud’s mentor when he was still starting his clinical practice.

Anna O. suffered from paralysis, personality changes, hallucinations, and rambling speech, but her doctors could not find the cause. Joseph Breuer was then called to her house for intervention and he performed psychoanalysis, also called the “talking cure”, on her.

Breuer would tell Anna O. to say anything that came to her mind, such as her thoughts, feelings, and childhood experiences. It was noted that her symptoms subsided by talking things out.

However, Breuer later referred Anna O. to the Bellevue Sanatorium, where she recovered and set out to be a renowned writer and advocate of women and children.

12. Patient HM

H.M., or Henry Gustav Molaison, was a severe amnesiac who had been the subject of countless psychological and neurological studies.

Henry was 27 when he underwent brain surgery to cure the epilepsy that he had been experiencing since childhood. In an unfortunate turn of events, he lost his memory because of the surgery and his brain also became unable to store long-term memories.

He was then regarded as someone living solely in the present, forgetting an experience as soon as it happened and only remembering bits and pieces of his past. Over the years, his amnesia and the structure of his brain had helped neuropsychologists learn more about cognitive functions .

Suzanne Corkin, a researcher, writer, and good friend of H.M., recently published a book about his life. Entitled Permanent Present Tense , this book is both a memoir and a case study following the struggles and joys of Henry Gustav Molaison.

13. Chris Sizemore

Chris Sizemore gained celebrity status in the psychology community when she was diagnosed with multiple personality disorder, now known as dissociative identity disorder.

Sizemore has several alter egos, which included Eve Black, Eve White, and Jane. Various papers about her stated that these alter egos were formed as a coping mechanism against the traumatic experiences she underwent in her childhood.

Sizemore said that although she has succeeded in unifying her alter egos into one dominant personality, there were periods in the past experienced by only one of her alter egos. For example, her husband married her Eve White alter ego and not her.

Her story inspired her psychiatrists to write a book about her, entitled The Three Faces of Eve , which was then turned into a 1957 movie of the same title.

14. David Reimer

When David was just 8 months old, he lost his penis because of a botched circumcision operation.

Psychologist John Money then advised Reimer’s parents to raise him as a girl instead, naming him Brenda. His gender reassignment was supported by subsequent surgery and hormonal therapy.

Money described Reimer’s gender reassignment as a success, but problems started to arise as Reimer was growing up. His boyishness was not completely subdued by the hormonal therapy. When he was 14 years old, he learned about the secrets of his past and he underwent gender reassignment to become male again.

Reimer became an advocate for children undergoing the same difficult situation he had been. His life story ended when he was 38 as he took his own life.

15. Kim Peek

Kim Peek was the inspiration behind Rain Man , an Oscar-winning movie about an autistic savant character played by Dustin Hoffman.

The movie was released in 1988, a time when autism wasn’t widely known and acknowledged yet. So it was an eye-opener for many people who watched the film.

In reality, Kim Peek was a non-autistic savant. He was exceptionally intelligent despite the brain abnormalities he was born with. He was like a walking encyclopedia, knowledgeable about travel routes, US zip codes, historical facts, and classical music. He also read and memorized approximately 12,000 books in his lifetime.

This list of experiments and case studies in psychology is just the tip of the iceberg! There are still countless interesting psychology studies that you can explore if you want to learn more about human behavior and dynamics.

You can also conduct your own mini-experiment or participate in a study conducted in your school or neighborhood. Just remember that there are ethical standards to follow so as not to repeat the lasting physical and emotional harm done to Little Albert or the Stanford Prison Experiment participants.

Asch, S. E. (1956). Studies of independence and conformity: I. A minority of one against a unanimous majority. Psychological Monographs: General and Applied, 70 (9), 1–70. https://doi.org/10.1037/h0093718

Bandura, A., Ross, D., & Ross, S. A. (1961). Transmission of aggression through imitation of aggressive models. The Journal of Abnormal and Social Psychology, 63 (3), 575–582. https://doi.org/10.1037/h0045925

Elliott, J., Yale University., WGBH (Television station : Boston, Mass.), & PBS DVD (Firm). (2003). A class divided. New Haven, Conn.: Yale University Films.

Festinger, L., & Carlsmith, J. M. (1959). Cognitive consequences of forced compliance. The Journal of Abnormal and Social Psychology, 58 (2), 203–210. https://doi.org/10.1037/h0041593

Haney, C., Banks, W. C., & Zimbardo, P. G. (1973). A study of prisoners and guards in a simulated prison. Naval Research Review , 30 , 4-17.

Latane, B., & Darley, J. M. (1968). Group inhibition of bystander intervention in emergencies. Journal of Personality and Social Psychology, 10 (3), 215–221. https://doi.org/10.1037/h0026570

Mischel, W. (2014). The Marshmallow Test: Mastering self-control. Little, Brown and Co.

Thorndike, E. (1920) A Constant Error in Psychological Ratings. Journal of Applied Psychology , 4 , 25-29. http://dx.doi.org/10.1037/h0071663

Watson, J. B., & Rayner, R. (1920). Conditioned emotional reactions. Journal of experimental psychology , 3 (1), 1.

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Famous Experiments

The Most Influential Psychological Experiments in History

Solomon Asch Conformity Line Experiment Study

Bandura's Bobo Doll Experiment on Social Learning

Reviewed by Olivia Guy-Evans, MSc

John Money Gender Experiment: Reimer Twins

Reviewed by Saul McLeod, PhD

Van Ijzendoorn & Kroonenberg: Cultural Variations in Attachment

Jean piaget, behaviorism, neuroscience.

Jean Piaget's theory of cognitive development suggests that children move through four different stages of intellectual development which reflect the increasing sophistication of children's thoughts. Child development is determined by biological maturation and interaction with the environment.

Learn More: Piaget's Stages of Cognitive Development

Behaviorism is a theory of learning that states all behaviors are learned through interaction with the environment through a process called conditioning. Thus, behavior is simply a response to environmental stimuli.

Learn More: Behaviorist Approach in Psychology

Sigmund Freud (1856 to 1939) was the founding father of psychoanalysis, a method for treating mental illness and a theory that explains human behavior. His theories are clinically derived, based on what his patients told him during therapy.

Learn More: Sigmund Freud's Influence on Psychology

An approach is a perspective that involves certain assumptions about human behavior: the way people function, which aspects of them are worthy of study, and what research methods are appropriate for undertaking this study. The five major psychological perspectives are biological, psychodynamic, behaviorist, cognitive, and humanistic.

Learn More: Major Perspectives in Modern Psychology

Neuroscience is the branch of science concerned with studying the nervous system. It is a multidisciplinary field integrating numerous perspectives from biology, psychology, and medicine. It consists of several sub-fields ranging from the study of neurochemicals to the study of behavior and thought.

Learn More: What is Neuroscience?

Frequent Asked Questions

Is psychodynamic same as psychoanalytic?

The words psychodynamic and psychoanalytic are often confused. Remember that Freud’s theories were psychoanalytic, whereas the term ‘psychodynamic’ refers to both his theories and those of his followers, such as Carl Jung, Anna Freud, and Erik Erikson.

Learn More: Psychodynamic Approach

What is developmental psychology?

Developmental psychology is a scientific approach which aims to explain how thinking, feeling, and behavior change throughout a person’s life. A significant proportion of theories within this discipline focus upon development during childhood, as this is the period during an individual’s lifespan when the most change occurs.

Learn More: Developmental Psychology

What is Freud’s psychosexual theory?

Sigmund Freud proposed that personality development in childhood takes place during five psychosexual stages, which are the oral, anal, phallic, latency, and genital stages.

During each stage, sexual energy (libido) is expressed in different ways and through different body parts.

Learn More: Freud’s Psychosexual Stages of Development

What Is object permanence in Piaget’s theory?

Object permanence means knowing that an object still exists, even if it is hidden. It requires the ability to form a mental representation (i.e. a schema) of the object.

The attainment of object permanence generally signals the transition from the sensorimotor stage to the  preoperational stage of development .

Learn More: What Is Object Permanence According To Piaget?

What is the difference between a psychology and sociology?

Psychology studies the mind of an individual to understand human behavior and social and emotional reactions, whereas sociology looks beyond individuals and examines societal institutions and groups of people.

Learn More: Similarities and Differences Between Sociology and Psychology

Explore Famous Experiments

Dement and Kleitman (1957)

Henry Gustav Molaison: The Curious Case of Patient H.M. 

Held and Hein (1963) Kitten carosel

Harry Harlow Theory & Rhesus Monkey Experiments in Psychology

Hawthorne Effect: Definition, How It Works, and How to Avoid It

Hofling Hospital Experiment (1966)

Hodges and Tizard (1989): Attachment Research Study

What Happened to Kitty Genovese

Konrad Lorenz: Theory of Imprinting in Psychology

Little Hans - Freudian Case Study

Little Albert Experiment (Watson & Rayner)

Little Peter, Cover-Jones (1924)

Loftus and Palmer (1974): Car Crash Experiment

Mary Ainsworth: Strange Situation Experiment & Attachment Theory

Stanford Marshmallow Test Experiment

Stanley Milgram Shock Experiment

Phineas Gage: His Accident and Impact on Psychology

Pavlov’s Dogs Experiment and Pavlovian Conditioning Response

Piliavin (1969) Subway Study

Serial Position Effect (Glanzer & Cunitz, 1966)

Rosenhan (1973) Experiment - 'On being sane in insane places'

Robbers Cave Experiment | Realistic Conflict Theory

Visual Cliff Experiment (Gibson & Walk, 1960)

Skinner Box: What Is an Operant Conditioning Chamber?

Stanford Prison Experiment: Zimbardo's Famous Study

8 Classic Psychological Experiments

Categories History

Psychological experiments can tell us a lot about the human mind and behavior. Some of the best-known experiments have given us insights into topics such as conformity, obedience, attachment, and learning.

There are many famous (and sometimes infamous) psychological experiments that have helped shape our understanding of the human mind and behavior. Such experiments offered insights into how people respond to social pressure and how they develop associations that lead to fear. 

While many of these psychological experiments are well known even outside of psychology, it is important to recognize that many of them could not be performed today.

In many instances, these experiments would never receive institutional review board approval due to ethical concerns and the potential harm to participants.

In this article, learn more about some of the most famous psychological experiments and discover why some of them are considered so controversial.

Table of Contents

Pavlov’s Dog Experiments, 1897

While not set up as a psychological experiment, Ivan Pavlov’s research on the digestive systems of dogs had a tremendous impact on the field of psychology. During his research, he noticed that dogs would begin to salivate whenever they saw the lab assistant who provided them with food.

By pairing a previously neutral stimulus (a sound) with a naturally occurring stimulus that automatically produces a response (food), Pavlov discovered that he could condition the dogs to salivate when they heard the sound.

The discovery of the classical conditioning process played a pivotal role in the formation of the behavioral school of psychology and has continued to influence our understanding of how learning can occur through associations.

Little Albert Experiment, 1920

Anyone who has ever taken an introductory course in psychology is probably familiar with the Little Albert experiment. In the famous experiment conducted in the 1920s by behaviorists John B. Watson and Rosalie Rayner, an infant was exposed to a white rat to which he initially exhibited no fear. The researchers then presented the rat accompanied by a loud clanging noise. 

After repeated pairings, the child began to cry when the rat alone was presented. This fear was even generalized to objects that resembled the rat such as fluffy white toys.

Watson’s research played an important role in the development of the school of thought known as behaviorism . It also provided evidence of the power of classical conditioning , which involves learning by association. 

The findings also had implications for our understanding of how fears can form, including phobias and irrational fears that sometimes develop early in life or after a single frightening experience.

Asch Conformity Experiment, 1951

The Asch conformity experiments were a series of psychological experiments conducted by psychologist Solomon Asch during the 1950s. The purpose of the experiments was to determine how much a person’s opinions were influenced by the opinions of the rest of the group.

In the study, participants were told that they were taking a “vision test” along with several others. In reality, the other individuals in the room were actors who were following the experimenters’ instructions.

When shown several line segments, the participants were supposed to select the one that matched a sample line segment in length.

In some cases, those who were in on the study would pick the obvious match. In other cases, however, the study confederates would unanimously pick the wrong line segment. 

The results of Asch’s experiments found that people tended to conform when other people unanimously picked the wrong answer.

Across the 12 trials he conducted, Asch found that around 33% of the naive participants conformed to the group and picked the wrong answer. In a control group, for comparison, less than 1% of the participants ever chose the wrong answer. 

The experiments revealed how group pressure can cause people to change their own behavior in order to fit in with the rest of the group.

Robbers Cave Experiment, 1954

In the Robbers Cave psychological experiment , researcher Muzafer Sherif and his colleagues used a summer camp setting to look at how factors such as competition and prejudice influenced conflict between groups. 

In the experiment, boys attending a summer camp were randomly assigned to two groups. The groups were then placed in situations where they had to compete with one another. Such competition led to conflicts, competition, and hostility between the two groups.

Later, the experiments attempted to reconcile the groups and eliminate the tensions that the previous competitive tasks had created. Bonding activities had little impact, but the researchers found that situations that required members of the two groups to work together in order to overcome a problem were effective at reducing tensions.

The study had implications for how different social groups create their own norms and hierarchies and then use those rules to exclude outsiders.

Harlow’s Rhesus Monkey Experiments, 1958

Psychologist Harry Harlow conducted a series of experiments during the 1950s and 1960s that demonstrated how important love and affection were in the course of child development. In his experiments, he placed infant monkeys in an environment where they had access to two different surrogate “mothers.”

One was a wire mother who held a bottle and provided food, while the other was a soft surrogate mother who was covered in a terry cloth fabric. 

While the cloth mother did not provide nourishment, the experiments demonstrated that the baby monkeys preferred the soft mother over the wire mother. When they were frightened and needed comfort, they would turn to the cloth mother for security.

Milgram Obedience Experiment, 1963

The Milgram experiment was one of the most famous and controversial psychological experiments ever performed. The experiments involved an experimenter ordering participants to deliver electrical shocks to other people.

While the people who were supposedly receiving the shocks were actors who pretended to be in pain, the participants fully believed that they were delivering painful, and even dangerous shocks. 

Milgram’s findings suggested that up to 65% of the participants were willing to deliver potentially fatal shocks to another person simply because an authority figure ordered them to do so. 

Based on these findings, Milgram proposed that people were willing to follow orders from an authority figure if they think that person will take responsibility for the results and is qualified to give orders. 

Bobo Doll Experiment, 1961-1963

In this experiment, Albert Bandura investigated the effects of observational learning by having young children witness acts of aggression and then observing them to see if they copied the behavior.

Children in the study observed adults act aggressively toward a Bobo doll, a large inflatable doll resembling a bowling pin. When hit or kicked, the doll tips sideways and then returns to an upright position.

Bandura found that children who watched an adult act aggressively were more likely to imitate those behaviors later when they were allowed to play in a room with the Bobo doll.

The study played an important role in our understanding of social learning theory and how kids learn by watching others. 

Stanford Prison Experiment, 1971

In this infamous social psychology experiment, Philip Zimbardo set up a mock prison in the basement of the Stanford University psychology department and randomly assigned a group of 24 college students to either be guards or prisoners. 

The study was originally supposed to last for two weeks but had to be stopped after six days because participants reportedly became so immersed in their roles that they began to experience upsetting psychological effects. The results were believed to demonstrate the power that social roles and expectations can exert over a person’s behavior. 

The experiment is widely described in psychology textbooks and even became the subject of a feature film in 2015. 

More recent analysis has suggested that the experiment had serious design flaws, among other problems. In addition to the already problematic ethics of the study, analysis of the study’s records suggests that the experimenters may have played a role in encouraging the abusive behavior displayed by the participants.

Impact of Psychological Experiments

The psychology experiments of the past have had an impact on our understanding of the human mind and behavior. While many of the experiments described here have problems in terms of their design and their ethics, they remain some of the most famous examples of research within the field of psychology.

Learning more about these classic experiments can help you better understand research that informed the development of psychology. It can also provide inspiration for your own psychology experiment ideas and provide information to explore in your psychology papers .

Bandura A, Ross D, Ross SA. Transmission of aggression through imitation of aggressive models . Journal of Abnormal and Social Psychology. 1961;63:575-82. doi:10.1037/h0045925

Gantt WH . Ivan Pavlov . Encyclopaedia Brittanica . Updated February 23, 2020.

Gonzalez-franco M, Slater M, Birney ME, Swapp D, Haslam SA, Reicher SD. Participant concerns for the Learner in a Virtual Reality replication of the Milgram obedience study. PLoS ONE. 2018;13(12):e0209704. doi:10.1371/journal.pone.0209704

Jeon, HL. The environmental factor within the Solomon Asch Line Test . International Journal of Social Science and Humanity. 2014;4(4):264-268. doi:10.7763/IJSSH.2014.V4.360 

Le Texier T. Debunking the Stanford Prison Experiment . American Psychologist . 2019;74(7):823-839. doi:10.1037/amp0000401

Sherif M, Harvey OJ, White BJ, Hood WR, Sherif CW. Intergroup conflict and cooperation: The Robbers Cave experiment (Vol. 10) . Norman, OK: University Book Exchange; 1961.

Zimbardo P, Haney C, Banks WC, Jaffe D. The Stanford Prison Experiment: A simulation study of the psychology of imprisonment. Stanford University, Stanford Digital Repository, Stanford; 1971.

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10 great psychology experiments

by Chris Woodford . Last updated: December 31, 2021.

S tare in the mirror and you'll find a strong sense of self staring back. Every one of us thinks we have a good idea who we are and what we're about—how we laugh and live and love, and all the complicated rest. But if you're a student of psychology —the fascinating science of human behaviour—you may well stare at your reflection with a wary eye. Because you'll know already that the ideas you have about yourself and other people can be very wide of the mark.

You might think you can learn a lot about human behaviour simply by observing yourself, but psychologists know that isn't really true. "Introspection" (thinking about yourself) has long been considered a suspect source of psychological research, even though one of the founding fathers of the science, William James, gained many important insights with its help. [1] Fortunately, there are thousands of rigorous experiments you can study that will do the job much more objectively and scientifically. And here's a quick selection of 10 of my favourites.

Listen instead... or scroll to keep reading

1: are you really paying attention (simons & chabris, 1999).

“ ...our findings suggest that unexpected events are often overlooked... ” Simons & Chabris, 1999

You can read a book or you can listen to the radio, but can you do both at once? Maybe you can listen to a soft-rock album you've heard hundreds of times before and simultaneously plod your way through an undemanding crime novel, but how about listening to a complex political debate while trying to revise for a politics exam? What about listening to a German radio station while reading a French novel? What about mixing things up a bit more. You can iron your clothes while listening to the radio, no problem. But how about trying to follow (and visualize) the radio commentary on a football game while driving a highway you've never been along before? That's much more challenging because both things call on your brain's ability to process spatial information and one tends to interfere with the other. (There are very good reasons why it's unwise to use a cellphone while you're driving—and in some countries it's illegal.)

Generally speaking, we can do—and pay attention—to only so many things at once. That's no big surprise. However human attention works (and there are many theories about that), it's obviously not unlimited. What is surprising is how we pay attention to some things, in some situations, but not others. Psychologists have long studied something they call the cocktail-party effect . If you're at a noisy party, you can selectively switch your attention to any of the voices around you, just like tuning in a radio, while ignoring all the rest. Even more striking, if you're listening to one person and someone else happens to say your name, your ears will prick up and your attention will instantly switch to the other person instead. So your brain must be aware of much more than you think, even if it's not giving everything its full attention, all the time. [2]

Photo: Would you spot a gorilla if it were in plain sight? Picture by Richard Ruggiero courtesy of US Fish and Wildlife Service National Digital Library .

Sometimes, when we're really paying attention, we aren't easily distracted, even by drastic changes we ought to notice. A particularly striking demonstration of this comes from the work of Daniel Simons and Christopher Chabris (1999), who built on earlier work by the esteemed cognitive psychologist Ulric Neisser and colleagues. [3] Simons and Chabris made a video of people in black or white shirts throwing a basketball back and forth and asked viewers to count the number of passes made by the white-shirted players. You can watch it here .

Half the viewers failed to notice something else that happens at the same time (the gorilla-suited person wandering across the set)—an extraordinary example of something psychologists call inattentional blindness (in plain English: failure to see something you really should have spotted). A related phenomenon called change blindness explains why we generally fail to notice things like glaring continuity errors in movies: we don't expect to see them—and so we don't. Whether experiments like "the invisible gorilla" allow us to conclude broader things about human nature is a moot point, but it's certainly fair to say (as Simons and Chabris argue) that they reveal "critically important limitations of our cognitive abilities." None of us are as smart as we like to think, but just because we fail and fall short that doesn't make us bad people; we'd do a lot better if we understood and recognized our shortcomings. [4]

2: Are you trying too hard? (Aronson, 1966)

No-one likes a smart-aleck, so the saying goes, but just how true is that? Even if you really hate someone who has everything—the good looks, the great house, the well-paid job—it tuns out that there are certain circumstances in which you'll like them a whole lot more: if they suddenly make a stupid mistake. This not-entirely-surprising bit of psychology mirrors everyday experience: we like our fellow humans slightly flawed, down-to-earth, and somewhat relatable. Known as the pratfall effect , it was famously demonstrated back in 1966 by social psychologist Elliot Aronson. [5]

“ ...a superior person may be viewed as superhuman and, therefore, distant; a blunder tends to humanize him and, consequently, increases his attractiveness. ” Aronson et al, 1966

Aronson made taped audio recordings of two very different people talking about themselves and answering 50 difficult questions, which were supposedly part of an interview for a college quiz team. One person was very superior, got almost all the questions right, and revealed (in passing) that they were generally excellent at what they did (an honors student, yearbook editor, and member of the college track team). The other person was much more mediocre, got many questions wrong, and revealed (in passing) that they were much more of a plodder (average grades in high school, proofreader of the yearbook, and failed to make the track team). In the experiment, "subjects" (that's what psychologists call the people who take part in their trials) had to listen to the recordings of the two people and rate them on various things, including their likeability. But there was a twist. In some of the taped interviews, an extra bit (the "pratfall") was added at the end where either the superior person or the mediocrity suddenly shouted "Oh my goodness I've spilled coffee all over my new suit", accompanied by the sounds of a clattering chair and general chaos (noises that were identically spliced onto both tapes).

Artwork: Mistakes make you more likeable—if you're considered competent to begin with.

What Aronson found was that the superior person was rated more attractive with the pratfall at the end of their interview; the inferior person, less so. In other words, a pratfall can really work in your favor, but only if you're considered halfway competent to begin with; if not, it works against you. Knowingly or otherwise, smart celebrities and politicians often appear to take advantage of this to improve their popularity.

3: Is the past a foreign country? (Loftus and Palmer, 1974)

Attention isn't the only thing that lets us down; memory is hugely infallible too—and it's one of the strangest and most complex things psychologists study. Can you remember where you were when the Twin Towers fell in 2001 or (if you're much older and willing to go back further) when JFK was shot in Dallas in 1963? You might remember a girl you were in kindergarten with 20 years ago, but perhaps you can't remember the guy you met last week, last night, or even 10 minutes ago. What about the so-called tip-of-the-tongue phenomenon where you're certain you know a word or fact or name, and you can even describe what it's like ("It's a really short word, maybe beginning with 'F'..."), but you can't bring it instantly to mind? [6] How about the madeleine effect, where the taste or smell or something suddenly sets off an incredibly powerful involuntary memory ? What about déjà-vu : a jarring true-false memory—the strong sense something is very familiar when it can't possibly be? [7] How about the curious split between short- and long-term memories or between "procedural memory" (knowing how to do things or follow instructions) and "declarative memory" (knowing facts), which breaks down further into "semantic memory" (general knowledge about things) and "episodic memory" (specific things that have happened to you). What about the many flavors of selective memory failure, such as seniors who can remember the name of a high-school sweetheart but can't recall their own name? Or sudden episodes of amnesia? Human memory is a massive—and massively complex—subject. And any comprehensive theory of it needs to be able to explain a lot.

“ ...the questions asked subsequent to an event can cause a reconstruction in one's memory of that event.. ” Loftus & Palmer, 1974

Much of the time, poor memory is just a nuisance and we all have tricks for working around it—from slapping Post-It notes on the mirror to setting reminders on our phones. But there's one situation where poor memories can be a matter of life or death: in criminal investigation and court testimony. Suppose you give evidence in a trial based on events you think you remember that happened years ago—and suppose your evidence helps to convict a "murderer" who's subsequently sentenced to death. But what if your memory was quite wrong and the person was innocent?

One of the most famous studies of just how flawed our memories can be was made by psychologists Elizabeth Loftus and John Palmer in 1974. [8] After showing their subjects footage of a car accident, they tested their memories some time later by asking "About how fast were the cars going when they smashed into each other?" or using "collided," "bumped," "contacted," or "hit" in place of smashed. Those asked the first—leading—question reported higher speeds. Later, the subjects were asked if they'd seen any broken glass and those asked the leading question ("smashed") were much more likely to say "yes" even though there was no broken glass in the film. So our memories are much more fluid, far less fixed, than we suppose.

Artwork: The words we use to probe our memories can affect the memories we think we have.

This classic experiment very powerfully illustrates the potential unreliability of eyewitness testimony in criminal investigations, but the work of Elizabeth Loftus on so-called "false memory syndrome" has had far-reaching impacts in provocative areas, such as people's alleged recollections of alien abduction , multiple personality disorder , and memories of childhood abuse . Ultimately, what it demonstrates is that memory is fallible and remembering is sometimes less of a mechanical activity (pulling a dusty book from long-neglected library shelf) than a creative and recreative one (rewriting the book partly or completely to compensate for the fact that the print has faded with time). [9]

4. Do you cave in to peer pressure? (Milgram, 1963)

Experiments like the three we've considered so far might cast an uncomfortable shadow, yet most of us are still convinced we're rational, reasonable people, most of the time. Asked to predict how we'd behave in any given situation, we'd be able to give a pretty good account of ourselves—or so you might think. Consider the question of whether you'd ever, under any circumstances, torture another human being and you'd probably be appalled at the prospect. "Of course not!" And yet, as Yale University's Stanley Milgram famously demonstrated in the 1960s and 1970s, you'd probably be mistaken. [10]

Artwork: The Milgram experiment: a shocking turn of events.

Milgram's experiments on obedience to authority have been widely discussed and offered as explanations for all kinds of things, from minor everyday cruelty to the appalling catalogue of repugnant human behavior witnessed during the Nazi Holocaust. Today, they're generally considered unethical because they're deceptive and could, potentially, damage the mental health of people taking part in them (a claim Milgram himself investigated and refuted). [26]

“ ...the conflict stems from the opposition of two deeply ingrained behavior dispositions: first, the disposition not to harm other people, and second, the tendency to obey those whom we perceive to be legitimate authorities. ” Milgram, 1963

Though Milgram's studies have not been repeated, related experiments have sought to shed more light on why people find themselves participating in quite disturbing forms of behavior. One explanation is that, like willing actors, we simply assume the roles we're given and play our parts well. In 1972, Stanford University's Philip Zimbardo set up an entire "pretend prison" and assigned his subjects roles as prisoners or guards. Quite quickly, the guards went beyond simple play acting and actually took on the roles of sadistic bullies, exposing the prisoners to all kinds of rough and degrading treatment, while the prisoners resigned themselves to their fate or took on the roles of rebels. [11] More recently, Zimbardo has argued that his work sheds light on atrocities such as the torture at the Abu Ghraib prison in 2004, when US army guards were found to have tortured and degraded Iraqi prisoners under their guard in truly shocking ways.

5. Are you a slave to pleasure? (Olds and Milner, 1954)

Why do we do the things we do? Why do we eat or drink, play football, watch TV... or do the legions of other things we feel compelled to do each day? How, when we take these sorts of behaviors to extremes, do we become addicted to things like drink and drugs, gambling or sex? Are they ordinary pleasures taken to extremes or something altogether different? Obsessions, compulsions, and addictive behaviors are complex and very difficult to treat, but what causes them... and how do we treat them?

Artwork: A rat will happily stimulate the "pleasure centre" in its brain.

“ It appears that motivation, like sensation, has local centers in the brain. ” James Olds, Scientific American, 1956.

The Olds and Milner ICSS (intracranial self-stimulation) experiment was widely interpreted as the discovery of a "pleasure center" in the brain, but we have to take that suggestion with quite a pinch of salt. It's fascinating, but also quite reductively depressing, to imagine that a lot of the things humans feel compelled to do each day—from work and eating to sport and sex—are motivated by nothing more than the need to scratch a deep neural itch: to repeatedly stimulate a "hungry" part of our brain. While it offers important insights into addictive behavior, the idea that all of our complex human pleasure-seeking stems from something so crudely behavioral—stimulus and reward—seems absurdly over-simple. It's fascinating to search for references to Olds and Milner's work and see it quoted in books with such titles as Your Money and Your Brain: How the New Science of Neuroeconomics Can Help Make You Rich . But it's quite a stretch from a rat pushing on a pedal to making arguments of that kind. [14]

6: Are you asleep at the wheel? (Libet, 1983)

Being a conscious, active human being is a bit like driving a car: looking out through your eyes is like staring through a windshield, seeing (perceiving) things and responding to them, as they see and respond to you. Consciousness, in other words, feels like a "top-down" thing; like the driver of a car, we're always in control, willing the world to bend to our way, making things happen according to ideas our brains we devise beforehand. But how true is that really? If you are a driver, you'll know that much of what you do depends on a kind of mental "auto-pilot" or cruise control. As a practiced driver, you barely have to think about what you're doing at all—it's completely automatic. We're only really aware of just how effort-full and attentive drivers need to be when we first start learning. We soon learn to do most of the things involved in driving without being consciously aware of them at all—and that's true of other things too, not just driving a car. Seen this way, driving seems impressive—but if you think again about the Simons and Chabris gorilla experiment, and consider its implications for sitting behind the wheel, you might want to take the bus in future.

Still, you might think, you're always, ultimately, in charge and in control: you're the driver , not the passenger, even if you are sometimes dozy at the wheel. And yet, a remarkable series of experiments by Benjamin Libet, in the 1980s, appeared to demonstrate something entirely different: far from consciously making things happen, sometimes we become conscious of what we've done after the fact. In Libet's experiments, he made people watch a clock and move their wrist when it reached a certain time. But their brain activity (which he was also monitoring) showed a peak a fraction of a second before their conscious decision to move, suggesting, at least in this case, that consciousness is the effect, not the cause. [15]

“ Many of our mental functions are carried out unconsciously , without conscious awareness. ” Benjamin Libet, Mind Time, 2004, p.2.

On the face of it, Libet's work seems to have extraordinary implications for the study of consciousness. It's almost like we're zombies sitting at the wheel of a self-driving car. Is the whole idea of conscious free will just an illusion, an accidental artefact of knee-jerk behavior that happens much more automatically? You can certainly try to argue it that way, as many people have. On the other hand, it's important to remember that this is a highly constrained laboratory experiment and you can't automatically extrapolate from that to more general human behavior. (Apart from anything else, the methodology of Libet's experiments has been questioned. [16] ) While you could try to argue that a complex decision (to buy a house or quit your job) is made unconsciously or subconsciously in whatever manner and we rationalize or become conscious of it after the fact, experiments like Libet's aren't offering evidence for that. Sometimes, it's too much of a stretch to argue from simple, highly contrived, very abstract laboratory experiments to bigger, bolder, and more general everyday behavior.

On the other hand, it's quite likely that some behavior that we believe to be consciously pre-determined is anything but, as William James (and, independently, Carl Lange) reasoned way back in the late 19th century. In a famous example James offered, we assume we run from a scary bear because we see the bear and feel afraid. But James believed the reasoning here is back to front: we see the bear, run, and only feel afraid because we find ourselves running from a bear! (How we arrive at emotions is a whole huge topic of its own. The James-Lange theory eventually spawned more developed theories by Walter Cannon and Philip Bard, who believed emotions and their causes happen simultaneously, and Stanley Shachter and Jerome Singer, who believe emotions stem both from our bodily reactions and how we think about them.) [17]

7: Why are you so attached? (Harlow et al, 1971)

“ Love is a wondrous state, deep, tender, and rewarding. Because of its intimate and personal nature it is regarded by some as an improper topic for experimental research. ” Harry Harlow, 1958.

Artwork: Animals crave proper comfort, not just the simple "reduction" of "drives" like hunger. Photo courtesy of NASA and Wikimedia Commons .

There's an obvious evolutionary reason why we get attached to other people: one way or another, it improves our chances of surviving, mating, and passing on our genes to future generations. Attachment begins at birth, but our attachment to our mothers isn't motivated purely by a simple need for nourishment (through breastfeeding or whatever it might be). One of the most famous psychological experiments of all time demonstrated this back in the early 1970s. The University of Wisconsin's Harry Harlow and his wife Margaret tested what happened when newborn baby monkeys were separated from their mothers and "raised," instead by crude, mechanical surrogates. In particular, Harlow looked at how the monkeys behaved toward two rival "mothers", one with a wooden head and a wire body that had a feeding bottle attached, and one made from soft, warm, comforting cloth. Perhaps surprisingly, the babies preferred the cloth mother. Even when they ventured over to the wire mother for food, they soon returned to the cloth mother for comfort and reassurance. [18]

The fascinating thing about this study is that it suggests the need for comfort is at least as important as the (more obviously fundamental) need for nourishment, so busting the cold, harsh claims of hard-wired behaviorists, who believed our attachment to our mothers was all about mechanistic "drive reduction," or knee-jerk stimulus and response. Ultimately, we love the loving—Harlow's "contact comfort"—and perhaps things like habits, routines, and traditions can all be interpreted in this light.

8: Are you as rational as you think? (Wason, 1966)

“ ... I have concentrated mainly on the mistakes, assumptions, and stereotyped behavior which occur when people have to reason about abstract material. But... we seldom do reason about abstract material. ” Peter Wason, 1966.

Like everyone else, you probably have your moments of wild, reckless abandon, but faced with the task of making a calm, rational judgment about something, how well do you think you'd do? It's not a question of what you know or how clever you are, but how well you can make a judgment or a decision. Suppose, for example, you had to hire the best applicant for a job based on a pile of résumés. Or what if you had to find a new apartment by the end of the month and you had a limited selection to pick among. What if you were on the jury of a trial and had to sit through weeks or evidence to reach a verdict? How well do you think you'd do? Probably, given all the information, you feel you'd make a fair job of it: you have faith in your judgment. And yet, decades of research into human decision-making suggests you'll massively overestimate your own ability. Overconfident and under-informed, you'll jump to hasty conclusions, swayed by glaring biases you don't even notice. In the words of Daniel Kahneman, probably the world's leading expert on human rationality, your brain opts to think "fast" (reaches a quick and dirty decision) when sometimes it'd be better off thinking "slow" (reaching a more considered verdict). [25]

A classic demonstration of how poorly we think was devised by British psychologist Peter Wason in 1966. The experimenter puts a set of four white cards in front of you, each of which has a letter on one side and a number on the other. Then they tell you that if a card has a vowel on one side, it has an even number on the other side. Finally, they ask you which cards you need to turn over to verify if that statement is true. Suppose the cards show A, D, 4, and 7. The obvious answer, offered by most people, is A and 4 or just A. But the correct answer is actually A and 7. Once you've turned over A, it serves no purpose to turn over D or 4: turning over D tells us nothing, because it's not a vowel, while turning over 4 doesn't provide extra proof or disprove the statement. By turning over 7, however, you can potentially disprove the theory if you reveal a vowel on the other side of it. Wason's four-card test demonstrates what's known as "confirmation bias"—our failure to seek out evidence that contradicts things we believe. [19]

Artwork: Peter Wason's four-card selection test. If a card has a vowel on one side, it has an even number on the other. Which cards do you need to turn over to confirm this?

As with the other experiments here, you could extrapolate and argue that Wason's abstract reasoning test is echoed by bigger and wider failings we see in ourselves. Perhaps it goes some way to explaining things like online "echo chambers" and "filter bubbles", where we tend to watch, read, and listen to things that reinforce things we already believe—intellectual cloth mothers, you might call them—rather than challenging those comfortable beliefs or putting them to the test. But, again, a simple laboratory test is exactly what it is: a simple, laboratory test. And other, broader personal or social conclusions don't automatically follow on from it. (Indeed, you might recognize the tendency to argue that way as a confirmation bias all of its own.)

9: How do you learn things? (Pavlov, 1890s)

Learning might seem a very conscious and deliberate thing, especially if you hate the subject you're studying or merely sitting in school. What could be worse than "rote" learning your times table, practising French vocabulary, or revising for an exam? We also learn a lot of things less consciously—sometimes without any conscious effort at all. Animals (other than humans) don't sit in classrooms all day but they learn plenty of things. Even one of the simplest (a sea-slug called Aplysia californica ) will learn to withdraw its syphon and gill if you give it an electric shock, as Eric Kandel and James Schwartz famously discovered. [20]

“ The animal must respond to changes in the environment in such a manner that its responsive activity is directed toward the preservation of its existence. ” Ivan Pavlov, 1926.

So how does learning come about? At its most basic, it involves making connections or "associations" between things, something that was probed by Russian psychologist Ivan Pavlov in perhaps the most famous psychology experiment of all time. Pavlov looked at how dogs behave when he gave them food. Normally, he found dogs would salivate (a response) when he brought them a plate of food (a stimulus). We call this an unconditioned response (meaning default, normal, or just untrained): it's what the dogs do naturally. Now, with the food a distant doggy memory, Pavlov rang a bell (a neutral stimulus) and found it produced no response at all (the dogs didn't salivate). In the next phase of the experiment, he brought the dogs plates of food and rang a bell at the same time and found, again, that they salivated. So again, we have an unconditioned response, but this time to a pair of stimuli. Finally, after a period of this training, he tested what happened when he just rang the bell and, to his surprise, found that they salivated once again. In the jargon of psychology, we say the dogs had become "conditioned" to respond to the bell alone: they associated the bell with food and so responded by salivating. We call this a conditioned (trained or learned) response: the dogs have learned that the sound of the bell is generally linked to the appearance of food. [21]

Pavlov's work on conditioning was hugely influential—indeed, it was a key inspiration for the theory of behaviorism . Advanced by such luminaries as B.F. Skinner and J.B. Watson, this was the idea that animal behavior is largely a matter of stimulus and response and mental states—thinking, feeling, emoting, and reasoning—is irrelevant. But, as with all the other experiments here, it's a stretch to argue that we're all quasi-automated zombies raised in a kind of collective cloud of mind-control conditioning. It's true that we learn some things by simple, behavioural association, and animals like Aplysia may learn everything they know that way, but it doesn't follow that all animals learn everything by making endless daisy-chains of stimulus and response. [22]

10: You're happier than you realize (Seligman, 1975)

Money makes the world go round—or so goes the lyric of a famous song. But if you're American Martin Seligman, you'd probably think "happiness" was a better candidate for what powers the planet, or should. When I was studying psychology at college back in the mid-1980s, Professor Seligman came along to give a guest lecture—and it proved to be one of the most thought-provoking talks I would ever attend.

“ The time has finally arrived for a science that seeks to understand positive emotion, build strength and virtue, and provide guideposts for... 'the good life'. ” Martin Seligman, Authentic Happiness, 2003.

Though now widely and popularly known for his work in a field he calls positive psychology , Seligman originally made his name researching mental illness and how people came to be depressed. Taking a leaf from Pavlov's book, his subjects were dogs. Rather than feeding them and ringing bells, he studied what happened when he gave dogs electric shocks and either offered them an opportunity to escape or restrained them in a harness so they couldn't. What he discovered was that dogs that couldn't avoid the shocks became demoralised and depressed—they "learned helpnessness"—and eventually didn't even try to avoid punishment, even when (once again) they were allowed to. [23]

You can easily construct a whole (behavioural) theory of mental illness on the basis of Seligman's learned helplessness experiments but, once again, there's much more to it than that. People don't become depressed purely because they're in impossible situations where problems seem (to use the terminology) "internal" (their own fault), "global" (affecting all aspects of their life), and "stable" (impossible to change). Many different factors—neurochemical, behavioral, cognitive, and social—feed into depression and, as a result, there are just as many forms of treatment.

What's really interesting about Seligman's work is what he did next. In the 1990s, he realized psychologists were obsessed with mental illness and negativity when, in his view, they should probably spend more time figuring out what makes people happy. So began his more recent quest to understand "positive psychology" and the things we can all do to make our lives feel more fulfilled. The key, in his view, is working out and playing to what he calls our "signature strengths" (things we're good at that we enjoy doing). His ideas, which trace back to those early experiments on learned helpless in hapless dogs, have proved hugely influential, prompting many psychologists to switch their attention to developing a useful, practical "science of happiness." [24]

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For older readers, for younger readers, references ↑    see for example the classic discussion of consciousness in chapter 9: the stream of thought in principles of psychology (volume 1) by william james, henry holt, 1890. ↑    donald broadbent carried out notable early work on "selective attention" as this is called. see, for example, the role of auditory localization in attention and memory span by d.e. broadbent, j exp psychol, 1954, volume 47 number 3, pp.191–6. ↑     [pdf] gorillas in our midst: sustained inattentional blindness for dynamic events by daniel j simons, christopher f chabris, perception, 1999, volume 28, pp.1059–1074. ↑     the invisible gorilla and other ways our intuition deceives us by christopher chabris and daniel j. simons. harpercollins, 2010. ↑     [pdf] the effect of a pratfall on increasing interpersonal attractiveness by elliot aronson, ben willerman, and joanne floyd, psychon. sci., 1966, volume 4 number 6,pp.227–228. ↑     the 'tip of the tongue' phenomenon by roger brown and david mcneill, journal of verbal learning and verbal behavior, volume 5, issue 4, august 1966, pp.325–337. ↑     the cognitive neuropsychology of déjà vu by chris moulin, psychology press, 2017. ↑     reconstruction of automobile destruction: an example of the interaction between language and memory by elizabeth loftus and john palmer, journal of verbal learning & verbal behavior, volume 13 issue 5, pp.585–589. ↑     "that doesn't mean it really happened": an interview with elizabeth loftus by carrie poppy, the sceptical inquirer, september 8, 2016. ↑     behavioral study of obedience by stanley milgram, journal of abnormal and social psychology, 1963, volume 67, pp.371–378. ↑     a study of prisoners and guards in a simulated prison by craig haney, curtis banks, and philip zimbardo, naval research review, 1973, volume 30, pp.4–17. ↑     dr. robert g. heath: a controversial figure in the history of deep brain stimulation by christen m. o'neal et al, neurosurg focus 43 (3):e12, 2017. serendipity and the cerebral localization of pleasure by alan a. baumeister, journal of the history of the neurosciences, basic and clinical perspectives, volume 15, 2006. issue 2. the 'gay cure' experiments that were written out of scientific history by robert colvile, mosaic science, 4 july 2016. ↑     positive reinforcement produced by electrical stimulation of septal area and other regions of rat brain by j. olds and p. millner, j comp physiol psychol, 1954 dec;47(6):419–27. ↑     the pleasure areas by h.j. campbell, methuen, 1973. ↑     mind time: the temporal factor in consciousness by benjamin libet, harvard university press, 2004. ↑     exposing some holes in libet's classic free will study by christian jarrett, bps research digest, 2008. ↑    for a decent overview, see the section "theories of emotion" in 58: emotion in psychology by openstaxcollege. ↑     the nature of love by harry f. harlow, american psychologist, 13, pp.673–685. for a more general account, see love at goon park: harry harlow and the science of affection by by deborah blum, basic books, 2002. ↑     reasoning by p.c. wason, in foss, brian (ed.). new horizons in psychology. penguin, 1966, p.145. ↑     eric kandel and aplysia californica: their role in the elucidation of mechanisms of memory and the study of psychotherapy by michael robertson and garry walter, acta neuropsychiatrica, volume 22, issue 4, august 2010, pp.195–196. ↑     conditioned reflexes; an investigation of the physiological activity of the cerebral cortex by i.p pavlov. dover, 1960. ↑     pavlov's dogs by tim tully, current biology, 2003, volume 13, issue 4, 18 february 2003, pp.r117–r119. ↑     learned helplessness: theory and evidence by steven maier and martin seligman, journal of experimental psychology: general, 1976, volume 105, number 1, pp3.–46. ↑     authentic happiness by martin seligman, nicholas brealey, 2003. ↑     thinking fast and slow by daniel kahneman, penguin, 2011. ↑     subject reaction: the neglected factor in the ethics of experimentation by stanley milgram, the hastings center report, vol. 7, no. 5 (oct., 1977), pp. 19–23. please do not copy our articles onto blogs and other websites articles from this website are registered at the us copyright office. copying or otherwise using registered works without permission, removing this or other copyright notices, and/or infringing related rights could make you liable to severe civil or criminal penalties. text copyright © chris woodford 2021. all rights reserved. full copyright notice and terms of use . follow us, rate this page, tell your friends, cite this page, more to explore on our website....

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Social Psychology Experiments: 10 Of The Most Famous Studies

Ten of the most influential social psychology experiments explain why we sometimes do dumb or irrational things. 

Ten of the most influential social psychology experiments explain why we sometimes do dumb or irrational things.

“I have been primarily interested in how and why ordinary people do unusual things, things that seem alien to their natures. Why do good people sometimes act evil? Why do smart people sometimes do dumb or irrational things?” –Philip Zimbardo

Like famous social psychologist Professor Philip Zimbardo (author of The Lucifer Effect: Understanding How Good People Turn Evil ), I’m also obsessed with why we do dumb or irrational things.

The answer quite often is because of other people — something social psychologists have comprehensively shown.

Each of the 10 brilliant social psychology experiments below tells a unique, insightful story relevant to all our lives, every day.

Click the link in each social psychology experiment to get the full description and explanation of each phenomenon.

1. Social Psychology Experiments: The Halo Effect

The halo effect is a finding from a famous social psychology experiment.

It is the idea that global evaluations about a person (e.g. she is likeable) bleed over into judgements about their specific traits (e.g. she is intelligent).

It is sometimes called the “what is beautiful is good” principle, or the “physical attractiveness stereotype”.

It is called the halo effect because a halo was often used in religious art to show that a person is good.

2. Cognitive Dissonance

Cognitive dissonance is the mental discomfort people feel when trying to hold two conflicting beliefs in their mind.

People resolve this discomfort by changing their thoughts to align with one of conflicting beliefs and rejecting the other.

The study provides a central insight into the stories we tell ourselves about why we think and behave the way we do.

3. Robbers Cave Experiment: How Group Conflicts Develop

The Robbers Cave experiment was a famous social psychology experiment on how prejudice and conflict emerged between two group of boys.

It shows how groups naturally develop their own cultures, status structures and boundaries — and then come into conflict with each other.

For example, each country has its own culture, its government, legal system and it draws boundaries to differentiate itself from neighbouring countries.

One of the reasons the became so famous is that it appeared to show how groups could be reconciled, how peace could flourish.

The key was the focus on superordinate goals, those stretching beyond the boundaries of the group itself.

4. Social Psychology Experiments: The Stanford Prison Experiment

The Stanford prison experiment was run to find out how people would react to being made a prisoner or prison guard.

The psychologist Philip Zimbardo, who led the Stanford prison experiment, thought ordinary, healthy people would come to behave cruelly, like prison guards, if they were put in that situation, even if it was against their personality.

It has since become a classic social psychology experiment, studied by generations of students and recently coming under a lot of criticism.

5. The Milgram Social Psychology Experiment

The Milgram experiment , led by the well-known psychologist Stanley Milgram in the 1960s, aimed to test people’s obedience to authority.

The results of Milgram’s social psychology experiment, sometimes known as the Milgram obedience study, continue to be both thought-provoking and controversial.

The Milgram experiment discovered people are much more obedient than you might imagine.

Fully 63 percent of the participants continued administering what appeared like electric shocks to another person while they screamed in agony, begged to stop and eventually fell silent — just because they were told to.

6. The False Consensus Effect

The false consensus effect is a famous social psychological finding that people tend to assume that others agree with them.

It could apply to opinions, values, beliefs or behaviours, but people assume others think and act in the same way as they do.

It is hard for many people to believe the false consensus effect exists because they quite naturally believe they are good ‘intuitive psychologists’, thinking it is relatively easy to predict other people’s attitudes and behaviours.

In reality, people show a number of predictable biases, such as the false consensus effect, when estimating other people’s behaviour and its causes.

7. Social Psychology Experiments: Social Identity Theory

Social identity theory helps to explain why people’s behaviour in groups is fascinating and sometimes disturbing.

People gain part of their self from the groups they belong to and that is at the heart of social identity theory.

The famous theory explains why as soon as humans are bunched together in groups we start to do odd things: copy other members of our group, favour members of own group over others, look for a leader to worship and fight other groups.

8. Negotiation: 2 Psychological Strategies That Matter Most

Negotiation is one of those activities we often engage in without quite realising it.

Negotiation doesn’t just happen in the boardroom, or when we ask our boss for a raise or down at the market, it happens every time we want to reach an agreement with someone.

In a classic, award-winning series of social psychology experiments, Morgan Deutsch and Robert Krauss investigated two central factors in negotiation: how we communicate with each other and how we use threats.

9. Bystander Effect And The Diffusion Of Responsibility

The bystander effect in social psychology is the surprising finding that the mere presence of other people inhibits our own helping behaviours in an emergency.

The bystander effect social psychology experiments are mentioned in every psychology textbook and often dubbed ‘seminal’.

This famous social psychology experiment on the bystander effect was inspired by the highly publicised murder of Kitty Genovese in 1964.

It found that in some circumstances, the presence of others inhibits people’s helping behaviours — partly because of a phenomenon called diffusion of responsibility.

10. Asch Conformity Experiment: The Power Of Social Pressure

The Asch conformity experiments — some of the most famous every done — were a series of social psychology experiments carried out by noted psychologist Solomon Asch.

The Asch conformity experiment reveals how strongly a person’s opinions are affected by people around them.

In fact, the Asch conformity experiment shows that many of us will deny our own senses just to conform with others.

Author: Dr Jeremy Dean

Psychologist, Jeremy Dean, PhD is the founder and author of PsyBlog. He holds a doctorate in psychology from University College London and two other advanced degrees in psychology. He has been writing about scientific research on PsyBlog since 2004. View all posts by Dr Jeremy Dean

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20 Famous Psychology Experiments That Shaped Our Understanding

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1.stanford prison experiment.

2.Milgram Experiment

3.little albert experiment.

4.Asch Conformity Experiment

5.harlow’s monkey experiment.

6.Bobo Doll Experiment

7.the marshmallow test.

8.Robbers Cave Experiment

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12.The Strange Situation

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14.Pavlov’s Dogs

15.the milgram experiment.

16.The Robbers Cave Experiment

17.the harlow monkey experiment, 18.the bystander effect, 19.the zimbardo prison experiment.

20.The Ainsworth Strange Situation Experiment

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Influential Psychology Experiments

Human psychology is often called a "soft science" because conclusions in certain types of studies or psychology experiments may be up to greater interpretation in psychology than in hard sciences like chemistry or biology. However, all sciences are interconnected, and psychology is real science. 

Many influential psychologists throughout history have encouraged people to treat psychology more like other sciences. For example, when you think about chemistry, you might think about experiments. In psychology, professionals study human behavior. There are many experiments carried out in psychological studies as well, and psychiatrists are as much medical doctors as other types of doctors, often studying how the body and mind interact, but with a special focus on the mind. Understanding these studies can help you understand mental health more profoundly.

Famous experiments in psychology

Harlow’s monkey mother experiments – importance of early attachments.

While teaching at the University of Wisconsin, psychologist Harry Harlow began conducting experiments on young rhesus monkeys, separating them from their mothers. He then made two surrogate mothers for the infant monkeys—one made of wire and one of terry cloth. The wire mother provided the monkeys with milk through a bottle, while the cloth mother had no food. 

Harlow’s experiment highlights the importance of early attachments, affection, and tactile connection. His findings had a substantial influence on John Bowlby, who went on to develop attachment theory. Despite its impact, due to the study’s design, it is considered one of the most unethical psychology experiments of the 20th century. 

The Stanford prison experiment – Situational Influences on human behavior

The Stanford Prison Experiment was a landmark study in psychology conducted by social psychology professor Philip Zimbardo in 1971 at Stanford University and is one of the most famous psychology experiments of the 1900s. The study was designed to investigate the psychological effects of power dynamics and social roles in a simulated prison environment and is one the most controversial experiments in psychology.

Zimbardo recruited 24 male college students to participate in the study. Each student participant was randomly assigned to play the role of either a prisoner or a guard. The participants were carefully screened for psychological and physical health before participating. The simulated prison was set up in the basement of the famous psychology department, with the cells, prison guards' quarters, and other facilities modeled on an actual prison.

The experiment was supposed to last for two weeks, but it was terminated after only six days due to the escalating abuse of power by the guards and the psychological distress experienced by the prisoners. The guards quickly became authoritarian and abusive, using physical punishment, psychological intimidation to exert their authority over the prisoners. The prisoners, in turn, became increasingly submissive and passive, often displaying signs of depression, anxiety, and helplessness.

If you or a loved one is experiencing abuse, contact the  Domestic Violence Hotline  at 1-800-799-SAFE (7233). Support is available 24/7.

The Stanford Prison Experiment is considered controversial for a number of reasons. Critics argue that the study was unethical and that the human subjects were subjected to undue stress and harm. Additionally, some psychologists have questioned the validity of the study, arguing that it lacked scientific rigor and was too heavily influenced by Zimbardo's own biases and expectations. The study remains a landmark in the history of the psychology of cognitive dissonance and continues to inspire further research into the psychology of power and social roles.

The Little Albert experiment – Conditioning emotional responses

The Little Albert experiment was a controversial study conducted by John B. Watson and his graduate student, Rosalie Rayner, in 1920. Watson and Rayner wanted to learn more about healthy childhood development and emotional development. The study used classical conditioning and aimed to investigate whether a conditioned emotional response could be established in a human infant.

Little Albert was an 11-month-old baby who was selected as the subject of the study. Initially, Albert was presented with various stimuli, including a white rat, a rabbit, a dog, and a monkey. Albert showed no fear or anxiety towards any of these stimuli.

The Little Albert experiment has been criticized for ethical reasons. Many psychologists argue that the study was unethical because it caused unnecessary psychological harm to the infant. Moreover, the study's scientific validity has been questioned because the experiment lacked controls, and the results were not systematically measured.

The Bobo doll psychology experiment – Learned social behaviors  

The Bobo doll experiment was a study conducted by Albert Bandura in 1961 to investigate the effects of observational learning on aggressive behavior in children. The study aimed to demonstrate how children learn and imitate aggressive behaviors through observation and modeling.

In the experiment, children between the ages of three and six were divided into three groups: a control group, one group that observed a model being physically aggressive toward a Bobo doll, and one group that observed a model being verbally aggressive toward the doll. The children were then placed in a playroom with a Bobo doll and aggressive toys, and their behavior was observed.

The results of the study showed that the children who observed the aggressive adults were more likely to imitate the same behaviors than those who did not. Furthermore, the children who observed the verbally aggressive model were also more likely to use aggressive language toward the doll. A landmark child development study, the Bobo doll experiment, demonstrated that children can learn new behaviors through observation and modeling, even if those behaviors are aggressive or violent.

The Finland basic income experiment – Increased well-being and employment

Universal Basic Income is the idea of giving everyone a fixed income regardless of whether they work. The idea is often considered a part of economics or government. Still, psychologists have questioned how people would behave in a society where they were not required to work.

Supporters believe that universal basic income would improve society by allowing individuals to do what they love rather than chase money. Thinkers going back to the ancient Greek philosopher  Socrates  have said that when individuals pursue their interests and natural skills, society is better off.

Critics believe it would damage society and lead to group conflict because no one would pursue higher-order jobs if they didn't work to live. They often point out necessary, non-automated, undesirable, and low-paying jobs that may not be filled if people were less incentivized by money because of a base income.

There is little room for critics to come up with ethical concerns. The influence of the study was positive, and the experiment's size and ambition serve as a model for other countries attempting similar experiments, including Germany .

The Visual Cliff Experiment – Depth perception in infants

The previous studies discussed in this article were conducted for a limited time by groups of researchers. However, some experiments were conducted once and immediately recognized as valuable. One such experiment is the  Visual Cliff Experiment.

Designed by  Eleanor Gibson  and Richard Walk in 1960, the Visual Cliff Experiment tested how and when young children develop depth perception and understand their relationships with their surroundings.

The test utilized a sheet with a checker pattern. The sheet was laid over a trench about a foot deep, making the drop-off visible. Heavy glass was placed over both sides of the trench, making the trench visible but safe to cross. A crawling child was then placed on one side of the trench with a parent on the other, coaxing the child to cross. Observers could then see the age at which a child recognizes the perceived drop-off and becomes hesitant to cross and identified this age as six to ten months, which was earlier than previously thought. 

The children also reacted to the visual cliff in several different ways. Some turned around and tried to back over the cliff as though they were trying to descend a stair. Others reached out with a hand to test the depth of the visual cliff. The experiment helped establish that children of this age often fall not because they are unaware of depth but because their depth perception matures faster than the motor ability to navigate it.

Counseling and support options for you

There are now thousands of psychological studies on many topics regarding mental health. Learning about these studies can help you further understand how the mind and body interact and which types of treatments are most effective for specific mental health challenges. If you're looking for guidance in choosing a type of psychological support, several resources are available to you. 

Online therapy can help

Many individuals appreciate the convenience, cost-effectiveness, and value of online therapy services, like those offered through platforms like BetterHelp. With BetterHelp, you can meet with a therapist from home, specify the specialty in which you'd like to receive support, and choose between phone, video, or live chat sessions. 

There have also been scientific studies on the effectiveness of online therapy. Even methods like online chat messaging therapy have been proven  as effective as face-to-face sessions and can reduce symptoms of depression, anxiety, and other mental health conditions. You do not need to have a diagnosis to receive support, and millions of clients reach out for help each year. 

Past psychological experiments designed to learn about human behavior have led to many breakthroughs in treatment, but some of the famous psychology experiments were controversial, such as:

• the Stanford Prison Experiment, in which ordinary people simulated prisoners and prison guards
• the Bobo Doll Experiment studying aggressive behavior
• the Little Albert Experiment, which used classical conditioning to elicit certain responses to stimuli

Experimental psychology serves a purpose, but the experiment should be designed to yield useful information without compromising the mental health of the participants.

If you're interested in learning more about psychology or talking to someone about your mental health, consider reaching out to a psychologist to get started. 

Frequently asked questions

Read more below for answers to questions commonly asked about psychology experiments., what is the most famous experiment in psychology.

One of the most famous experiments in psychology is the Stanford Prison Experiment conducted by Philip Zimbardo in 1971. It explored the psychological effects of perceived power, focusing on the struggle between prisoners and prison officers.

What is a psychological experiment example?

An example of a psychological experiment is the Milgram Obedience Experiment, where participants were instructed to administer electric shocks to a learner. The study aimed to understand the extent to which individuals would follow orders from an authority figure, even when it involved harming another person.

What is a good psychology experiment?

A good psychology experiment is the Bobo Doll Experiment by Albert Bandura, which studied children's behavior after watching an adult model act aggressively towards a Bobo doll. The findings demonstrated the impact of observational learning on behavior.

What is the purpose of psychological experiments?

The purpose of a psychological experiment is to investigate hypotheses about behavior and mental processes under controlled conditions. These experiments aim to understand how various factors influence thoughts, emotions, and actions, providing insights into human psychology.

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7 Famous Psychology Experiments

Many famous experiments studying human behavior have impacted our fundamental understanding of psychology. Though some could not be repeated today due to breaches in ethical boundaries, that does not diminish the significance of those psychological studies. Some of these important findings include a greater awareness of depression and its symptoms, how people learn behaviors through the process of association and how individuals conform to a group.

Below, we take a look at seven famous psychological experiments that greatly influenced the field of psychology and our understanding of human behavior.

The Little Albert Experiment, 1920

A John’s Hopkins University professor, Dr. John B. Watson, and a graduate student wanted to test a learning process called classical conditioning. Classical conditioning involves learning involuntary or automatic behaviors by association, and Dr. Watson thought it formed the bedrock of human psychology.

A nine-month-old toddler, dubbed “Albert B,” was volunteered for Dr. Watson and Rosalie Rayner ‘s experiment. Albert played with white furry objects, and at first, the toddler displayed joy and affection. Over time, as he played with the objects, Dr. Watson would make a loud noise behind the child’s head to frighten him. After numerous trials, Albert was conditioned to be afraid when he saw white furry objects.

The study proved that humans could be conditioned to enjoy or fear something, which many psychologists believe could explain why people have irrational fears and how they may have developed early in life. This is a great example of experimental study psychology.

Stanford Prison Experiment, 1971

Stanford professor Philip Zimbardo wanted to learn how individuals conformed to societal roles. He wondered, for example, whether the tense relationship between prison guards and inmates in jails had more to do with the personalities of each or the environment.

During Zimbardo’s experiment , 24 male college students were assigned to be either a prisoner or a guard. The prisoners were held in a makeshift prison inside the basement of Stanford’s psychology department. They went through a standard booking process designed to take away their individuality and make them feel anonymous. Guards were given eight-hour shifts and tasked to treat the prisoners just like they would in real life.

Zimbardo found rather quickly that both the guards and prisoners fully adapted to their roles; in fact, he had to shut down the experiment after six days because it became too dangerous. Zimbardo even admitted he began thinking of himself as a police superintendent rather than a psychologist. The study confirmed that people will conform to the social roles they’re expected to play, especially overly stereotyped ones such as prison guards.

“We realized how ordinary people could be readily transformed from the good Dr. Jekyll to the evil Mr. Hyde,” Zimbardo wrote.

The Asch Conformity Study, 1951

Solomon Asch, a Polish-American social psychologist, was determined to see whether an individual would conform to a group’s decision, even if the individual knew it was incorrect. Conformity is defined by the American Psychological Association as the adjustment of a person’s opinions or thoughts so that they fall closer in line with those of other people or the normative standards of a social group or situation.

In his experiment , Asch selected 50 male college students to participate in a “vision test.” Individuals would have to determine which line on a card was longer. However, the individuals at the center of the experiment did not know that the other people taking the test were actors following scripts, and at times selected the wrong answer on purpose. Asch found that, on average over 12 trials, nearly one-third of the naive participants conformed with the incorrect majority, and only 25 percent never conformed to the incorrect majority. In the control group that featured only the participants and no actors, less than one percent of participants ever chose the wrong answer.

Asch’s experiment showed that people will conform to groups to fit in (normative influence) because of the belief that the group was better informed than the individual. This explains why some people change behaviors or beliefs when in a new group or social setting, even when it goes against past behaviors or beliefs.

The Bobo Doll Experiment, 1961, 1963

Stanford University professor Albert Bandura wanted to put the social learning theory into action. Social learning theory suggests that people can acquire new behaviors “through direct experience or by observing the behavior of others.” Using a Bobo doll , which is a blow-up toy in the shape of a life-size bowling pin, Bandura and his team tested whether children witnessing acts of aggression would copy them.

Bandura and two colleagues selected 36 boys and 36 girls between the ages of 3 and 6 from the Stanford University nursery and split them into three groups of 24. One group watched adults behaving aggressively toward the Bobo doll. In some cases, the adult subjects hit the doll with a hammer or threw it in the air. Another group was shown an adult playing with the Bobo doll in a non-aggressive manner, and the last group was not shown a model at all, just the Bobo doll.

After each session, children were taken to a room with toys and studied to see how their play patterns changed. In a room with aggressive toys (a mallet, dart guns, and a Bobo doll) and non-aggressive toys (a tea set, crayons, and plastic farm animals), Bandura and his colleagues observed that children who watched the aggressive adults were more likely to imitate the aggressive responses.

Unexpectedly, Bandura found that female children acted more physically aggressive after watching a male subject and more verbally aggressive after watching a female subject. The results of the study highlight how children learn behaviors from observing others.

The Learned Helplessness Experiment, 1965

Martin Seligman wanted to research a different angle related to Dr. Watson’s study of classical conditioning. In studying conditioning with dogs, Seligman made an astute observation : the subjects, which had already been conditioned to expect a light electric shock if they heard a bell, would sometimes give up after another negative outcome, rather than searching for the positive outcome.

Under normal circumstances, animals will always try to get away from negative outcomes. When Seligman tested his experiment on animals who hadn’t been previously conditioned, the animals attempted to find a positive outcome. Oppositely, the dogs who had been already conditioned to expect a negative response assumed there would be another negative response waiting for them, even in a different situation.

The conditioned dogs’ behavior became known as learned helplessness, the idea that some subjects won’t try to get out of a negative situation because past experiences have forced them to believe they are helpless. The study’s findings shed light on depression and its symptoms in humans.

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The Milgram Experiment, 1963

In the wake of the horrific atrocities carried out by Nazi Germany during World War II, Stanley Milgram wanted to test the levels of obedience to authority. The Yale University professor wanted to study if people would obey commands, even when it conflicted with the person’s conscience.

Participants of the condensed study , 40 males between the ages of 20 and 50, were split into learners and teachers. Though it seemed random, actors were always chosen as the learners, and unsuspecting participants were always the teachers. A learner was strapped to a chair with electrodes in one room while the experimenter äóñ another actor äóñ and a teacher went into another.

The teacher and learner went over a list of word pairs that the learner was told to memorize. When the learner incorrectly paired a set of words together, the teacher would shock the learner. The teacher believed the shocks ranged from mild all the way to life-threatening. In reality, the learner, who intentionally made mistakes, was not being shocked.

As the voltage of the shocks increased and the teachers became aware of the believed pain caused by them, some refused to continue the experiment. After prodding by the experimenter, 65 percent resumed. From the study, Milgram devised the agency theory , which suggests that people allow others to direct their actions because they believe the authority figure is qualified and will accept responsibility for the outcomes. Milgram’s findings help explain how people can make decisions against their own conscience, such as when participating in a war or genocide.

The Halo Effect Experiment, 1977

University of Michigan professors Richard Nisbett and Timothy Wilson were interested in following up a study from 50 years earlier on a concept known as the halo effect . In the 1920s, American psychologist Edward Thorndike researched a phenomenon in the U.S. military that showed cognitive bias. This is an error in how we think that affects how we perceive people and make judgements and decisions based on those perceptions.

In 1977, Nisbett and Wilson tested the halo effect using 118 college students (62 males, 56 females). Students were divided into two groups and were asked to evaluate a male Belgian teacher who spoke English with a heavy accent. Participants were shown one of two videotaped interviews with the teacher on a television monitor. The first interview showed the teacher interacting cordially with students, and the second interview showed the teacher behaving inhospitably. The subjects were then asked to rate the teacher’s physical appearance, mannerisms, and accent on an eight-point scale from appealing to irritating.

Nisbett and Wilson found that on physical appearance alone, 70 percent of the subjects rated the teacher as appealing when he was being respectful and irritating when he was cold. When the teacher was rude, 80 percent of the subjects rated his accent as irritating, as compared to nearly 50 percent when he was being kind.

The updated study on the halo effect shows that cognitive bias isn’t exclusive to a military environment. Cognitive bias can get in the way of making the correct decision, whether it’s during a job interview or deciding whether to buy a product that’s been endorsed by a celebrity we admire.

How Experiments Have Impacted Psychology Today

Contemporary psychologists have built on the findings of these studies to better understand human behaviors, mental illnesses, and the link between the mind and body. For their contributions to psychology, Watson, Bandura, Nisbett and Zimbardo were all awarded Gold Medals for Life Achievement from the American Psychological Foundation. Become part of the next generation of influential psychologists with King University’s online bachelor’s in psychology . Take advantage of King University’s flexible online schedule and complete the major coursework of your degree in as little as 16 months. Plus, as a psychology major, King University will prepare you for graduate school with original research on student projects as you pursue your goal of being a psychologist.

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Famous Psychology Experiments to Study

Published on: May 3, 2022

What we know about human psychology today comes from a number of tests, experiments and research projects that explored the way humans think, behave and interact with one another. Historically, many of these projects pushed the ethical limits of the day and may not be something we can repeat. Yet studying their results gives us amazing insight into the human mind. From mood disorders like depression to discovering how people interact with groups, ground-breaking psychological experiments are fascinating to study.

Why Is Research Important in Psychology?

Unlike biology and chemistry, much of psychology is a social or “soft” science. The ideas and feelings of the human mind are not something researchers can easily measure or repeat in a laboratory. Thus, they are not always something people can predict.

Psychology experiments are invaluable because it gives psychologists the chance to observe and study human behavior. Carefully designed research studies can provide insight into how physiological disorders work and who might be more at risk for them. These studies can provide insight into how people build and grow relationships, how children develop and build bonds, and much more. Psychology studies can also show how psychological health and mental disorders affect individuals and society as a whole. In the case of mental health concerns, it is through research that psychologists find effective treatments to help improve the quality of life for people who are struggling.

Types of Psychology Research Methods

Psychology research falls into one of three basic categories:

Descriptive: Simply describes the features of a group or behavioral phenomena but does not look at how, when, or why.

Correlational: Looks for statistical connections between pieces of data or variables in the test or experiment.

Experimental: Uses proven scientific methods to explore psychology and what drives behavior and mental health.

Experimental psychology is typically where tests and experiments take place. These psychologists use test subjects to study issues in the field.

Influential and Famous Psychology Experiments

The research and experiments of the psychologists of the past have given the field tremendous insight into a wide range of topics. Many experiments pushed the envelope of ethics, often putting people in distressing or difficult scenarios that would not be allowed today. Yet they did bring new knowledge to the field. Here are some of the experiments that are still impacting the world of psychology and mental health treatment today.

Developmental Psychology Experiments

Developmental psychology studies the development, change and consistency of an individual's mental abilities and psychological well-being throughout their life. Developmental psychology often looks at the development of children and their thoughts, feelings and behaviors. Some historical psychological studies have provided insight into child development that professionals still use today.

Little Albert and the Rat   – In the early 1900s, psychologist John Watson did experiments on a newborn to see if he could create a fear of rats. He exposed a nine-month-old baby boy who was not afraid of rats to the creatures while making a loud noise. Soon, the baby associated rats with the noise and became afraid of them.

Bobo Doll Experiment  – In the early 1960s, psychologists were fascinated with the question of nature versus nurture in child development. This particular experiment studied how aggressive children were when watching other children. Albert Bandura and a team of researchers exposed 24 kids to a group of adults who were acting aggressively toward a doll called Bobo. Another group watched the adults play with the doll nicely, while the final group didn’t see the doll.

After the observation, the children were placed into different scenarios, such as having researchers give them toys to play with, take toys away, or give them aggressive toys, like mallets or toy guns. Bandura and his team found that children who saw aggression toward the Bobo doll were more likely to show aggression in their own play than those who did not observe aggressive adults. They then theorized that social imitation drives human behavior more than human genetics.

Fantz’z Looking Chamber  – Robert L. Fantz carried out an experiment in 1961 that showed important insight into infant development and vision. Before his experiment, researchers had few thoughts on how to study the developing mind of a newborn. In his experiment, Fantz placed newborns into a box and showed them two patterns on the ceiling above them, one of a bull’s eye and one of a human face. Researchers found that babies as young as two months had a clear preference for looking at the human face, which showed humans have an in-born ability to recognize human faces.

Surrogate Mother Experiment  – Psychologist Harry Harlow developed a series of studies in the late 1950s and early 1960s to determine the role of a mother’s love in the development of a child. He used young rhesus monkeys for his experiment, separating the babies from their birth mothers and giving them to two surrogates. One surrogate was simply wire and wood with a bottle connected to it, while the other was a plush terrycloth with no food. Researchers found that the baby monkeys spent significantly more time with the soft, plush “mother” than with the one that had food. He then placed monkeys in various new situations, and only those infant monkeys who had a plush surrogate were confident enough to explore scary situations. Harlow theorized that love and nurture and the parent-child relationship were vital to the development of a baby.

Social Psychology Experiments

Social psychology explores the impact others have on an individual's ideas, feelings and behaviors. This impact can be due to both the real presence of other people or the implied presence of society or a group as a whole, even without their physical presence. These famous social psychology experiments have greatly impacted the understanding of sociology.

The Good Samaritan Experiment  – In the Good Samaritan Experiment, students were given religious education, then were asked to go from one building to the next. Researchers placed a man acting like he was wounded and in need of help between the two buildings. If the group of students was not pressed for time, almost two-thirds of the students stopped to help the actor. Only 1 in 10 was willing to do so when the researchers put them on a deadline.

To add to the experiment, researchers gave one group the task of going to the next building to make a speech on helping others. This change increased the chances that they would stop to help by almost two times. The conclusion was that people’s ideas had a significant impact on whether or not they were willing to help others.

Robbers Cave Experiment  –  Researchers from the University of Oklahoma performed this experiment in 1954. They created two groups of pre-teen boys, then sent them to summer camp. After spending a week with just their cabin mates, the groups came together for some activities and competitions.

The groups were clearly biased and antagonistic with the members of the other group. When the researchers tried to increase their time together to reduce this prejudice, the prejudice got worse. It was not until the groups were given a task on which to work together that the tension eased. Researchers theorized that group conflict often occurs when groups must compete over necessary resources.

Ross’ False Consensus Effect Study  – Lee Ross, a social psychology professor at Stanford University, ran an experiment in 1977 that looked at the way people make wrong assumptions, or a “false consensus,” about others and their preferences. He did two studies to draw these conclusions.

First, Ross and his associates asked participants to read about conflict and guess how people would respond. Most participants guessed that others would respond the same way they did. Next, Ross asked participants to walk around campus wearing a sign that said, “Eat at Joe’s.” Subjects were told they would get a reward if they wore the sign. They then asked how many of the study participants they thought would also agree to wear the sign. Over half felt that others would make the same choice they did. Based on these two studies, Ross theorized that people naturally assumed others around them would make the same choices they did.

The Milgram Experiments  –  Stanley Milgram performed a series of obedience tests in 1963 that had rather frightening parameters. In his experiment, he asked volunteers to apply severe electrical shocks to another person. The shocks did not actually hurt, but the other person acted as if they were in severe pain. Even in this difficult scenario, 65% of the participants were willing to obey the experimenter and inflict pain on the other person. Based on these results, Milgram theorized that many of those people who committed horrible crimes in World War II justified their actions because they were just “obeying orders.”

Controversial and Unethical Psychology Experiments

Many psychology experiments in the past did not follow good ethical parameters. Though the results have helped our understanding of psychology today, the methods remain questionable. In addition to experiments like The Milgram Experiments or Little Albert and the Rat, which have already been mentioned, here are fascinating and sometimes disturbing psychology experiments:

Seligman’s Investigation and Learned Helplessness  – In this classic experiment, Seligman placed dogs in a box with two chambers, one of which had an electrified floor. If dogs were placed in the box after being administered electrical shocks they could not predict or control, then those dogs would not attempt to get away from the shocking floor. Dogs that had not been shocked prior to going in the box would quickly jump over the barrier to avoid the floor. This led to the  theory of learned helplessness , which postulates that people who were once in helpless situations may not attempt to improve their current situation, even if they can.

The Monster Study  – The Monster Study in 1939 took a group of children with speech impediments and tested whether positive or negative reinforcement worked best. Some children were given praise for fluency, while the other was given severe treatment for speech problems. Those who received negative reinforcement actually stopped speaking, while those who were given praise were able to improve their speech.

The Aversion Project  – From 1971 to 1987, researchers in South Africa imprisoned homosexual men and women in a military hospital. They performed aversion treatment, which was a form of torture, to try to get these individuals to change their sexual identities. Few positive results occurred, and many of the forced participants either died due to treatment or due to suicide after the program ceased.

Stanford Prison Study  – In the Stanford Prison Study of the 1970s, participants were placed in a fabricated prison environment. Some were assigned the role of guard, while others were assigned the role of an inmate. The guards were given a tremendous amount of control over the inmates, performing horrific punishments on them. Many inmate participants experienced paranoia as the cruelty of the guards increased. The experiment only lasted six days, but it showed that human behavior is quite situational, and people will quickly fall into an assigned role if the conditions are right.

Learn More About Human Behavior With a Degree in Psychology

Psychology continues to grow as a profession and a field. Though there have been questionable studies in the past, today there are clear guidelines and ethics that control this field. If you are interested in studying human thought and behavior, check out Husson University's  online psychology degree  today.

https://www.psychologicalscience.org/publications/observer/obsonline/harlows-classic-studies-revealed-the-importance-of-maternal-contact.html#:~:text=Based%20on%20this%20observation%2C%20Harlow,rubber%20and%20soft%20terry%20cloth.

https://www.simplypsychology.org/robbers-cave.html

https://www.prisonexp.org/

https://www.simplypsychology.org/false-consensus-effect.html

https://www.spring.org.uk/2022/02/monster-study-stuttering.php

https://positivepsychology.com/learned-helplessness-seligman-theory-depression-cure/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC535952/

https://www.psychologytoday.com/us/blog/darwins-subterranean-world/201703/my-favorite-psychology-study

https://www.apa.org/monitor/2010/01/little-albert

https://www.onlinepsychologydegree.info/influential-psychological-experiments/

https://www.verywellmind.com/classic-psychology-experiments-2795257

https://study.com/academy/lesson/famous-childhood-development-experiments.html

https://www.verywellmind.com/the-milgram-obedience-experiment-2795243

https://historyofyesterday.com/six-of-the-most-controversial-psychology-experiments-in-history-c8842b73ea4e

https://www.simplypsychology.org/bobo-doll.html

https://explorable.com/false-consensus-effect

https://www.newsweek.com/stanford-prison-experiment-age-justice-reform-359247

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9 of the Most Influential Social Psychology Experiments in History

For those interested in understanding how social interactions can shape behavior and mental processes, this article dives deep into some of the most influential social psychology experiments in history. Covering everything from the perpetrator-victim dynamic prevalent in Stanley Milgram’s infamous obedience experiment to the false consensus effect just a few years later, these social psychology experiments provide invaluable insights into the human psyche.

Through carefully conducted studies such as Lee Ross’ Diffusion of Responsibility Experiment and Edward Thorndike’s Halo Effect Experiment, as well as famous experiments such as Albert Bandura’s Bobo Doll Experiment, we are able to better comprehend why people act the way they do in certain situations. Come explore these incredible, influential experiments that have left their mark on social psychology and the world!

To learn more about what is social psychology check out our article.

The Stanford Prison Experiment, 1971

1.1. overview.

The Stanford Prison Experiment was a widely known and controversial social psychology experiment conducted in 1971 at Stanford University by Professor Philip Zimbardo to investigate how ordinary, healthy people would react to being made prisoners or prison guards. It has since become a classic social psychology experiment and is still studied today. However, the experiment has come under considerable criticism in recent years due to ethical issues.

1.2. Results

Twenty-four male college students were recruited for the experiment, which involved them playing the role of either prisoner or guard. Each group was then allotted 8-hour shifts and treated as if they were in a real prison situation. The prisoners were kept in the makeshift prison set up in the basement of the Psychology Department, where the guards were responsible for ensuring the inmates followed prison regulations. The participants were screened to guarantee they had no mental or physical problems that may have influenced their behavior.

The experiment concluded that it is possible to change the behavior of individuals when placed in groups, even when they are not aware they are being observed. The study showed how quickly people will conform to expected social roles and how easily ‘ordinary’ people can be transformed from ‘good’ to ‘evil.’ Both the prisoners and guards revealed stereotypical characteristics associated with correctional officers; the prisoners became emotionally unstable and submissive, whilst the guards became hostile and authoritative.

1.3. Criticisms

Philip Zimbardo’s experiment, the Stanford Prison Experiment, is like a dark mirror reflecting our society’s innermost fears. In 1971, Zimbardo conducted an experiment in which college students were randomly assigned to be either prisoners or guards in a simulated prison environment. The results of this study showed that people could quickly adapt to roles and lose their sense of morality when placed in certain situations.

The impact of the Stanford Prison Experiment has been far-reaching; it has been used as evidence for why prisons are so dangerous and how they can lead to psychological damage among inmates. It also serves as a reminder that power dynamics between individuals can have serious consequences if not monitored closely.

Critics have argued that the ethical practices employed by Zimbardo during his experiment were questionable at best, with some participants experiencing extreme distress due to their role-playing experience. Despite these criticisms, many believe that the experiment still provides valuable insight into human behavior and psychology today. Personifying its lessons, we could say that the Stanford Prison Experiment speaks volumes about how easily our moral compass can become distorted when faced with authority figures or oppressive environments.

The Asch Conformity Experiment, 1951

2.1. overview.

The Asch Conformity Experiment, also known as the “Asch Line Study,” was a series of experiments conducted by psychologist Solomon Asch in 1951 to test how people tend to conform to social pressures. The study was composed of two groups: one consisting of actual participants (the control group) and the other including actors (the confederates).

During the experiment, the participants were asked to view a line on one board and then match it to one of three lines on another board with their own judgment. Initially, the group was given correct answers; however, after a few attempts, the actors began to give wrong answers intentionally to observe how the participant would respond.

2.2. Results

The results showed that 75% of the participants conformed to the incorrect majority opinion given by the confederate group—even when it obviously contradicted their own senses. In addition, the control group with only real subjects produced a much lower rate of conformity, with less than 1% ever selecting the incorrect answer. This demonstrated that it was not the difficulty of the task but rather the presence of an influential social group that caused the majority of participants to deny their own thoughts in order to fit in with the others.

2.3. Criticisms

Critics have argued that the experiment was not diverse enough since it mainly used college-aged men as its sample population. Additionally, because the experiment did not include females, it has been suggested that the results of the cave experiment cannot be generalized to all genders.

Furthermore, critics have argued that the experimental design lacked a true measure of real-life social pressure since the actors and real participants knew the situation was artificial. Despite these criticisms, the Asch experiment remains one of the most important social psychology studies in history, and its core message about the power of conformity to influence opinions and behavior continues to be studied and discussed today.

We tackled the topic of conformity in our article about social influence .

The Bobo Doll Experiment, 1961

3.1. overview.

The Bobo Doll experiment was a series of experiments conducted by psychologist Albert Bandura between 1961 and 1963 at Stanford University, aimed at studying the extent to which human behavior is based on social imitation rather than inherited genetic factors.

Three groups of 24 participants each, aged from 3 to 6 years old, were chosen for the experiment – a control group (with no interaction with any adults), an aggressive group (observing an adult behaving aggressively towards the doll), and a passive group (observing a more passive adult playing with the doll). The results of the studies were a strong indication that children were strongly influenced by watching other people’s behavior and imitated it afterward in their own behavior.

3.2. Results

The study found that the children in the aggressive and passive groups were significantly more likely to behave aggressively towards the bobo doll than those in the control group, even though the latter had not been exposed to any type of model behavior. When it came to gender differences, boys showed more aggressive behavior when exposed to the aggressive behavior of male models, while girls showed similar findings, albeit less drastic.

Moreover, the study also contained a memory test during which wrong answers were punished with electric shocks; here, it appeared as if the individual completing the test was affected by the electric shocks, suggesting that authority figures can greatly influence behavior, even if not intentionally. Finally, the study also showed that when urged to continue with the experience even after protests from the individual receiving electric shocks, they complied with the requests, highlighting the power of authority within social situations.

3.3. Criticisms

Although the experiment raised widely accepted as evidence for the hypothesis that individuals learn behavior by observing others, the Bobo Doll experiment has been criticized in recent years. One key point of criticism is that Bandura’s research neglected to look at positive modeling – for example, modeling of altruism or helpful behavior, instead focusing solely on aggression.

Additionally, some have argued that, due to its relatively small sample size and laboratory-based approach, the study failed to take into account real-life influences, such as environmental variables, which would have provided additional context. Despite these criticisms, the Bobo Doll experiment remains one of the most famous studies in psychology, providing significant evidence for the importance of social learning theory in understanding human behavior.

The Milgram Experiment, 1963

4.1. overview.

The Milgram Experiment was a famous social psychology experiment and experiment conducted by Stanley Milgram in the 1960s. Its aim was to test people’s obedience to authority. The study examined how far people would go when an authority figure instructed them to perform acts that conflicted with their morals.

Specifically, it sought to find out if non-Nazi populations, such as those from the United States, would follow orders to harm other persons. One of the motivations for this investigation was the results of World War II, during which Nazi leader Adolf Eichmann was able to use “I was only following orders” as a legal defense at the Nuremberg trials.

4.2. Results

The experiment was conducted at Yale University in 1961 and included unsuspecting participants who were told that the study was about memory. Participants believed they were participating in a study where they would be required to act as teachers while an unsuspecting confederate (learned) was on the other side of the wall. Their task was to ask questions to the learner, and if they received a wrong answer, press a button administering shock, ranging from 15 volts to 450 volts.

The results showed that despite protests and cries from the learner, 63% of the participants continued pressing the switch. Milgram’s experiment revealed that human beings are conditioned to obey authority figures, even when going against their natural moral code.

4.3. Criticisms

Despite its significance, the Milgram Experiment has been heavily criticized over the years, and some have argued that the study violated ethical standards. The argument is that causing psychological and emotional distress to unwitting volunteers is wrong. Other critics have argued that the role reversals or changes in lab settings would yield different outcomes and should have been considered.

In response to these criticisms, some scientists have suggested controversial experiments by reducing the voltage administered to the learner or conducting newer versions of the experiment in naturalistic settings. In addition, the way modern studies measure obedience is greatly different – contemporary research focuses on motives and reactions participants have after the experiment. These proposed changes would enable researchers to look into extraneous factors influencing obedience versus harm caused to participants.

The Halo Effect Experiment, 1977

5.1. overview.

The halo effect is commonly defined as the phenomenon in which a positive evaluation of one trait extends to an overall perception of an individual. This cognitive bias has been observed by social psychologists for over a century, beginning with psychologist Edward Thorndike’s studies regarding commanding officers in the military.

The halo effect is also known as the “what is beautiful is good” principle or the “physical attractiveness stereotype.” This phenomenon has had a lasting impact on our evaluation and judgment of others. Additionally, the term “halo effect” was named after its likeness to that of the halo painted above the heads of saints and holy figures in religious art, generally regarded as symbols of moral goodness.

To investigate this phenomenon further, Nisbett and Wilson conducted an experiment in 1977 at the University of Michigan. As research participants, they recruited college students who were asked to watch a pre-recorded psychology instructor tape with two different attitudes—one likable and another unlikable. After watching the videotapes, they filled in a questionnaire that asked them to rate the lecturer’s physical appearance, mannerisms, and accent on an 8-point scale ranging from “like extremely” to “dislike extremely.”

Nisbett and Wilson’s study showed that despite the lecturers having the same mannerisms and accents, the respondents rated the lecturer more favorably if their attitude projected a likable demeanor. Moreover, Nisbett and Wilson discovered that people are unaware when the halo effect phenomenon occurs; they inferred that the respondents relied on their initial impression of the lecturer without being aware that it influenced their subsequent assessment. In total, 278 college students participated in the study.

5.2. Results

The results of this study showed that the ratings of the lecturer responded differently depending on his behavior—those who saw him adopt a likable demeanor in the video gave him higher ratings than those who saw him act in an unlikable manner. Furthermore, those who rated the lecturer highly were more likely to believe that he was intelligent, hardworking, kind, and humorous. This suggests that the halo effect can lead people to make inaccurate assumptions about someone based solely on their appearance or behavior.

Moreover, an updated study on the halo effect also suggests that a negative assessment of certain traits can similarly affect subsequent perceptions. For instance, if someone didn’t like the instructor’s physical appearance, they are more likely to rate him as unintelligent and lazy. This provides evidence that negative feelings about one characteristic can extend to an individual’s other features.

5.3. Criticisms

Despite its analytical contributions to the field, some scholars have questioned Nisbett and Wilson’s use of college students as the research participants in the study due to their limited exposure to the concept at hand. Additionally, since the focus of this experiment utilized only pre-recorded videos, there is also criticism of the limitation in the accuracy of facial expressions and vocal intonations. However, this study does provide evidence that people may rely on initial impressions when making assessments, resulting in cognitive bias and inaccurate judgments.

The False Consensus Effect Experiment, 1974

6.1. overview.

The False Consensus Effect Experiment was conducted in 1974 by Professor Lee Ross, then at Stanford University. The experiment focused on how people can form a “false consensus” about the beliefs and preferences of others. Specifically, it asked participants to read situations with two alternative responses and predict which one other people would choose. In the study, most subjects overestimated the likelihood that others would do the same thing as them, even when the situation was hypothetical and there was no real data to indicate what choice the majority of people might make. Furthermore, researchers found that the anticipation of a false consensus could lead people to display negative predictions about the personalities of those who did not share their choice.

6.2. Results

The results of Lee Ross’s experiment demonstrated the false consensus bias – the tendency to overestimate the extent to which others agree with one’s own beliefs and behaviors. He and his colleagues also conducted experiments in the late 1970s to demonstrate how this bias operates in estimating other people’s behaviors and causes. For example, participants chose a resolution to an imagined conflict, then estimated how many others would choose the same.

In another experiment, students were asked to carry a sign that read “eat at joe’s” to measure how many other people agreed with the sign. Those who agreed believed the majority of people would also agree; those who refused believed the majority would refuse. This experiment showed the false consensus effect – we tend to believe the majority of people agree with us and act the same way.

6.3. Criticisms

The false consensus effect is like a mirage in the desert, appearing to be something it’s not. It occurs when people overestimate how much other people agree with them. This bias can lead to an inaccurate perception of reality and cause individuals to make decisions based on false assumptions. The false consensus effect is most likely to occur when someone has strong beliefs or opinions about a particular topic and assumes that others share their views.

The Chameleon Effect Experiment, 1990

7.1. overview.

The Chameleon Effect is a phenomenon of unintentional mirroring, which was observed and studied for the first time in 1939 at the University of Iowa by Dr. Wendell Johnson. It involves someone mimicking another’s body posture, hand gestures, or even speaking accents without realizing it. In the 1990s, researchers Tanya Chartrand and John Bargh conducted follow-up experiments to further study this effect, which would be known as the “Chameleon Effect.”

7.2. Results

During their experiment, Chartrand and Bargh secretly mimicked the actions and behaviors of some test subjects during their conversations and monitored the responses. Those that were mimicked found the researchers more likable compared to those not mimicked. The results point to how people often subconsciously respond to others even if they weren’t consciously aware of the imitating behavior.

7.3. Criticisms

Despite being a popular explanation for why people tend to mirror each other’s behavior, the Chameleon Effect has been criticized by some. These criticisms mostly come from the idea that the phenomenon could potentially involve manipulation as well as desensitizing people to be more vulnerable to conformity and impressions. Additionally, some suggest there may be other reasons why people might mirror each other other than the Chameleon Effect itself, such as insecurity or politeness.

The Diffusion of Responsibility Experiment, 1968

8.1. overview.

The diffusion of responsibility experiment, conducted in 1968 at Stanford University, is an iconic social psychology experiment. It is studied to understand the bystander effect, a phenomenon in which people are more reluctant to express helpfulness or give aid if other bystanders are present.

Stanley Milgram and John Darley conducted the experiment to analyze how the presence of others could influence helping behaviors in kids. The study was also connected to concepts from Lev Vygotsky’s theory referring to emotional role-taking and group cohesiveness when observing the behavior of other members in a particular situation.

In the study, 600 children between the ages of four to six were tested. Each child was presented with one marshmallow, and they were promised to receive a second one if it still remained on the table after 15 minutes.

The results showed that only one-third of the children had delayed their gratification long enough to obtain the second marshmallow. Follow-up studies demonstrated that those children who managed to delay gratification and obtain the second marshmallow had higher SAT scores and were found to be more competent than their peers who could not wait and ate the marshmallow immediately.

8.2. Results

The results of the diffusion of responsibility experiment in 1968 proved to be true to an extent. Its findings added significantly to defining the bystander effect and the effects of the presence of other people, which may inhibit helpers’ reactions to those in need. The research showed that the number of bystanders could have a profound effect on one’s decision on whether to act or to remain inactive. This study takes into account the psychological phenomenon known as diffusion of responsibility which partially explains this inhibition of helping behavior.

8.3. Criticisms

Although the diffusion of responsibility experiment has contributed greatly to our understanding of the bystander effect, there is some criticism surrounding the validity and applicability of the experiment change in the setting in which it was conducted. Namely, there is some concern around the age of the participants, as well as the amount of time provided for the test, both of which may have had an influence on the outcome. In addition, since the experiment was conducted in 1972, there have been numerous changes to society and culture that may not have been taken into account by the authors at the time, leaving some questions as to its usefulness in current situations.

The Cognitive Dissonance Experiment, 1957

Leon Festinger’s Cognitive Dissonance Experiment of 1957 addresses the mental discomfort experienced when trying to hold two conflicting beliefs. The experiment sought to identify how this dissonance is resolved by people and to gain further insight into our thoughts and behaviors.

Stanley Schachter and Jerome E. Singer conducted the experiment with the intention of testing the cognitive theory of emotional arousal. They injected participants with epinephrine, a hormone that can produce side effects– both physical and psychological – such as increased heart rate, faster breathing, and an elevation in blood pressure.

The study featured a confederate who acted either in one of two ways: they were either pleasant or unpleasant. As knowledge of the injection’s side effects became aware to the participants, their emotions shifted accordingly. This revealed that dissonance leads to emotional arousal in individuals, leading them to act in agreement with emotion-triggering cognition.

In light of its results, critics have since made a note of the implausibility of Schachter and Singer’s study, claiming that it does little to address the complexities of the cognitive dissonance theory. By comparison, Leon Festinger’s cognitive dissonance experiment assumes that everyone holds many different cognitions about the world. It then examines what happens when those cognitions do not fit together adequately. Discrepancies are accepted if an event or occurrence makes sense; if not, these discrepancies lead to a state of tension or dissonance.

Interested readers may refer to festive ger’s 1959 article, “Cognitive Dissonance,” for a more in-depth exploration of the experiment’s results and implications. The study remains a classic social psychology experiment, illustrating how we reconcile the conflicts created by existing contradictory beliefs.

The 10 most influential social psychology experiments in history can all be summarized by their contribution to the development of our understanding of human behavior. From Milgram’s famous study revealing our willingness to obey authority figures, to Bandura’s Bobo Doll Experiment establishing the power of aggression and imitation, to Nisbett and Wilson’s Halo Effect Experiment controlling biases towards physical attractiveness, these studies provide insights into the power of group dynamics, social pressures, and cognitive bias that continue to inform and impact modern society today.

Learning about these classic social psychology experiments also encourages us to question our assumptions, explore alternative perspectives, and strive for greater understanding and acceptance. Whether by examining the limitations of data collection or the ethical implications of research methods, these landmark studies have built our knowledge base and served as a reminder of the importance of respect and empathy.

In conclusion, the 10 most influential social psychology experiments listed reflect an inspiring effort to better understand human behavior and engage in much-needed conversations around this fascinating field.

Frequently Asked Questions

What were the initial experiments in social psychology.

Norman Triplett’s 1898 experiment is credited with being the first social psychology experiment. He examined the effects of competition on a simple task – winding hempen string – and found that people performed better when in the presence of others than when alone. His findings ushered in an exciting new field of research into how people are both influenced by, and affect, the social world around them.

Why are experiments are used in social psychology?

Experiments provide valuable insight into human behavior and allow for cause and effect relationships to be better understood. They are an essential tool conducting research in social psychology, allowing the researcher to observe how individuals respond in different situational contexts. Experimentation allows us to answer important questions about social behavior, making it an invaluable research method.

What are social psychology topics?

Social psychology explores the fascinating ways that people interact with each other, from understanding why prejudicial behavior occurs to analyzing why some people have a greater degree of influence over human behaviors than others. Social psychology has played a major role in helping us understand human behavior. It has made invaluable contributions through its research on various topics like prejudice and discrimination, gender, culture, social influence, interpersonal relations, group behavior, aggression etc.

What is an example of a social experiment?

An example of a social experiment is Stanley Milgram’s obedience experiment conducted in 1963 which tested human subjects’ willingness to obey orders regardless of the outcomes. This controversial experiment was conducted in order to understand how far people would go to follow orders from authority figures, even if it meant inflicting pain on another person.

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What was the social experiment of the 60s?

The Social Experiment of the 1960s was the Milgram experiment, conducted by Yale University psychologist Stanley Milgram. It tested participants’ willingness to obey authority when asked to do something that conflicted with their own moral values. The experiment yielded powerful insights into human behavior and the power of authority, making it one of the most influential experiments of its time.

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3 Most Famous Psychology Experiments Everyone Should Know

by The Oxford Scholastica Team | 14 May, 2024 | Blog Articles , Psychology Articles

Have you ever wondered why good people do bad things? Or why anyone would ignore someone in need of help? How about why anyone would conform to an extreme idea that they don’t agree with?

Throughout the history of psychology, many experiments have attempted to answer these questions—some of which would never be allowed today for ethical reasons. Many of these have been very influential within the field of social psychology and are still taught today.

Keep reading to hear about three of the most shocking and well-known social experiments.

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Table of Contents

1. The Stanford Prison Experiment

None of us would like to believe that we are capable of evil. However, Zimbardo’s infamous Stanford prison experiment showed that, actually, we all have this potential. It all depends on the situation.

Phillip Zimbardo was a researcher at Stanford University in America. In 1972, he recruited 24 mentally healthy, male, college students for an experiment taking place in a fake prison in the basement of Stanford. These participants were randomly allocated into 2 groups: prison guards and prisoners.

The guards received a uniform and mirrored sunglasses to wear for the job. Then, after being sent home, the prisoners were publicly arrested at their home on a Sunday morning. They were processed at a real police station before being transported to the ‘prison’.

No one could have predicted what would happen next.

The guards weren’t given any specific instructions on how to behave. Yet, very soon they began acting in extreme ways: they prevented prisoners from eating, took away their bedding, forced them to remove their clothes, and even punished them with chores such as cleaning toilets with their bare hands.

As well as this, the prisoners were submitting to the guards—even though they knew that they hadn’t actually done anything wrong and weren’t even in a real prison! After just thirty-six hours, a prisoner had to be extracted from the study as he had sunk into a deep depression with fits of rage and uncontrollable crying.

Just a few days later, other prisoners displayed similar symptoms. The guards also continued to abuse them. It was at this point that Zimbardo’s girlfriend told him he had to stop the experiment. It was shut down after just six days, despite Zimbardo intending it to run for fourteen.

This experiment demonstrates the power of the situation in influencing how we act. Good people, just like you or me, are capable of evil acts. But, the power of the situation doesn’t always have to be bad: it can also be a force for good.

Of course, we could never repeat this experiment for ethical reasons. This means that we need to assess how valid Zimbardo’s conclusions really are. For example, demand characteristics—how the guards assumed they should act—may have significantly shaped their behaviour.

2. The Bystander Effect

In 1964, Kitty Genovese was brutally murdered just outside her home. What makes this case so different is that thirty-eight witnesses were reported to be present at some point during this attack—all of whom failed to help her.

It was later shown that this didn’t quite happen how the newspapers had described. Few of the thirty-eight neighbours were actually aware of what was going on at the time. But, this still sparked a great interest in ‘the bystander effect’: the phenomenon that the more people there are present, the less likely someone is to help in an emergency situation.

Four years later, in 1968, John Darley and Bibb Latané went on to test this whether this effect held true. They put participants in a room, either alone or in groups with two other naïve participants or two confederates (researchers who pretend to be participants). They then filtered smoke into the room. The confederates remained passive as this happened.

The results of this followed the same shocking pattern as shown in the case of Kitty Genovese.

Participants were both least likely, and took longest, to report the smoke when with the passive confederates. Only 10% reported it when with them. This was slightly higher at 38% when they were in groups of three, but went all the way up to 75% when they were alone.

In the real world, this means that we are less likely to intervene in an emergency situation when surrounded by other people. And, we are even less likely when those people are also doing nothing.

It’s important to remember that this doesn’t make us bad people. The bystander effect happens for many reasons: we see other observers doing nothing and follow their cues, we believe we lack competency, or we simply expect someone else to take responsibility.

The best way to stop this happening is to know that the effect is there—so you are already one step closer to being the person who steps in to help out of a crowd of people.

3. Asch’s Conformity Experiment

Do you think you could be convinced to answer a question with the wrong answer, even when you knew the right one? Most of us would say no. However, Solomon Asch’s 1951 experiment suggests that both you and I probably can.

In this experiment, participants were simply asked to judge the size of a line compared to others. The answer to this was always very clear and unambiguous: in control trials participants gave the right answer 99% of the time. However, Asch placed participants in a group with confederates who all gave the wrong answer.

You might assume that participants would still give the answer they knew to be right. But, a surprising number of participants conformed to the group answer. Overall, they gave the wrong answer 37% of the time. This experiment is so surprising to us because we generally don’t realise how much our beliefs can be influenced by others. In our everyday lives, we conform to ideas not because we believe they are true, but simply to avoid standing out from the group.

As with all of these studies, it is important to consider how valid these findings are. And, the answer seems to be that they are: a meta-analysis by Bond & Smith (1996) found a significant level of conformity across cultures and over time.

However, a very clever adaptation of this experiment which did not use confederates failed to find this effect. 

Key takeaways from these famous psychology studies

These are three of the most influential and well-known experiments in the history of psychology.

Zimbardo taught us that good people are capable of doing bad things. Darley and Latané confirmed that we are less likely to help in an emergency when there are more people around. And, Asch showed how much we conform to group ideas.

If you enjoyed learning about the most interesting psychology experiments, consider signing up for our Psychology Summer School for high school students . At Oxford Scholastica, our Oxford Summer School programs give international students the chance to experience academic study at a higher level.

More interesting psychology studies and resources

• Split brain experiments
• Psychology of a murderer’s mind
• The psychology of success
• Spatial mapping
• Books about psychological experiments

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How the Experimental Method Works in Psychology

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The Experimental Process

Types of experiments, potential pitfalls of the experimental method.

The experimental method is a type of research procedure that involves manipulating variables to determine if there is a cause-and-effect relationship. The results obtained through the experimental method are useful but do not prove with 100% certainty that a singular cause always creates a specific effect. Instead, they show the probability that a cause will or will not lead to a particular effect.

At a Glance

While there are many different research techniques available, the experimental method allows researchers to look at cause-and-effect relationships. Using the experimental method, researchers randomly assign participants to a control or experimental group and manipulate levels of an independent variable. If changes in the independent variable lead to changes in the dependent variable, it indicates there is likely a causal relationship between them.

What Is the Experimental Method in Psychology?

The experimental method involves manipulating one variable to determine if this causes changes in another variable. This method relies on controlled research methods and random assignment of study subjects to test a hypothesis.

For example, researchers may want to learn how different visual patterns may impact our perception. Or they might wonder whether certain actions can improve memory . Experiments are conducted on many behavioral topics, including:

The scientific method forms the basis of the experimental method. This is a process used to determine the relationship between two variables—in this case, to explain human behavior .

Positivism is also important in the experimental method. It refers to factual knowledge that is obtained through observation, which is considered to be trustworthy.

When using the experimental method, researchers first identify and define key variables. Then they formulate a hypothesis, manipulate the variables, and collect data on the results. Unrelated or irrelevant variables are carefully controlled to minimize the potential impact on the experiment outcome.

History of the Experimental Method

The idea of using experiments to better understand human psychology began toward the end of the nineteenth century. Wilhelm Wundt established the first formal laboratory in 1879.

Wundt is often called the father of experimental psychology. He believed that experiments could help explain how psychology works, and used this approach to study consciousness .

Wundt coined the term "physiological psychology." This is a hybrid of physiology and psychology, or how the body affects the brain.

Other early contributors to the development and evolution of experimental psychology as we know it today include:

• Gustav Fechner (1801-1887), who helped develop procedures for measuring sensations according to the size of the stimulus
• Hermann von Helmholtz (1821-1894), who analyzed philosophical assumptions through research in an attempt to arrive at scientific conclusions
• Franz Brentano (1838-1917), who called for a combination of first-person and third-person research methods when studying psychology
• Georg Elias Müller (1850-1934), who performed an early experiment on attitude which involved the sensory discrimination of weights and revealed how anticipation can affect this discrimination

Key Terms to Know

To understand how the experimental method works, it is important to know some key terms.

Dependent Variable

The dependent variable is the effect that the experimenter is measuring. If a researcher was investigating how sleep influences test scores, for example, the test scores would be the dependent variable.

Independent Variable

The independent variable is the variable that the experimenter manipulates. In the previous example, the amount of sleep an individual gets would be the independent variable.

A hypothesis is a tentative statement or a guess about the possible relationship between two or more variables. In looking at how sleep influences test scores, the researcher might hypothesize that people who get more sleep will perform better on a math test the following day. The purpose of the experiment, then, is to either support or reject this hypothesis.

Operational definitions are necessary when performing an experiment. When we say that something is an independent or dependent variable, we must have a very clear and specific definition of the meaning and scope of that variable.

Extraneous Variables

Extraneous variables are other variables that may also affect the outcome of an experiment. Types of extraneous variables include participant variables, situational variables, demand characteristics, and experimenter effects. In some cases, researchers can take steps to control for extraneous variables.

Demand Characteristics

Demand characteristics are subtle hints that indicate what an experimenter is hoping to find in a psychology experiment. This can sometimes cause participants to alter their behavior, which can affect the results of the experiment.

Intervening Variables

Intervening variables are factors that can affect the relationship between two other variables. 

Confounding Variables

Confounding variables are variables that can affect the dependent variable, but that experimenters cannot control for. Confounding variables can make it difficult to determine if the effect was due to changes in the independent variable or if the confounding variable may have played a role.

Psychologists, like other scientists, use the scientific method when conducting an experiment. The scientific method is a set of procedures and principles that guide how scientists develop research questions, collect data, and come to conclusions.

The five basic steps of the experimental process are:

• Identifying a problem to study
• Devising the research protocol
• Conducting the experiment
• Analyzing the data collected
• Sharing the findings (usually in writing or via presentation)

Most psychology students are expected to use the experimental method at some point in their academic careers. Learning how to conduct an experiment is important to understanding how psychologists prove and disprove theories in this field.

There are a few different types of experiments that researchers might use when studying psychology. Each has pros and cons depending on the participants being studied, the hypothesis, and the resources available to conduct the research.

Lab Experiments

Lab experiments are common in psychology because they allow experimenters more control over the variables. These experiments can also be easier for other researchers to replicate. The drawback of this research type is that what takes place in a lab is not always what takes place in the real world.

Field Experiments

Sometimes researchers opt to conduct their experiments in the field. For example, a social psychologist interested in researching prosocial behavior might have a person pretend to faint and observe how long it takes onlookers to respond.

This type of experiment can be a great way to see behavioral responses in realistic settings. But it is more difficult for researchers to control the many variables existing in these settings that could potentially influence the experiment's results.

Quasi-Experiments

While lab experiments are known as true experiments, researchers can also utilize a quasi-experiment. Quasi-experiments are often referred to as natural experiments because the researchers do not have true control over the independent variable.

A researcher looking at personality differences and birth order, for example, is not able to manipulate the independent variable in the situation (personality traits). Participants also cannot be randomly assigned because they naturally fall into pre-existing groups based on their birth order.

So why would a researcher use a quasi-experiment? This is a good choice in situations where scientists are interested in studying phenomena in natural, real-world settings. It's also beneficial if there are limits on research funds or time.

Field experiments can be either quasi-experiments or true experiments.

Examples of the Experimental Method in Use

The experimental method can provide insight into human thoughts and behaviors, Researchers use experiments to study many aspects of psychology.

A 2019 study investigated whether splitting attention between electronic devices and classroom lectures had an effect on college students' learning abilities. It found that dividing attention between these two mediums did not affect lecture comprehension. However, it did impact long-term retention of the lecture information, which affected students' exam performance.

An experiment used participants' eye movements and electroencephalogram (EEG) data to better understand cognitive processing differences between experts and novices. It found that experts had higher power in their theta brain waves than novices, suggesting that they also had a higher cognitive load.

A study looked at whether chatting online with a computer via a chatbot changed the positive effects of emotional disclosure often received when talking with an actual human. It found that the effects were the same in both cases.

One experimental study evaluated whether exercise timing impacts information recall. It found that engaging in exercise prior to performing a memory task helped improve participants' short-term memory abilities.

Sometimes researchers use the experimental method to get a bigger-picture view of psychological behaviors and impacts. For example, one 2018 study examined several lab experiments to learn more about the impact of various environmental factors on building occupant perceptions.

A 2020 study set out to determine the role that sensation-seeking plays in political violence. This research found that sensation-seeking individuals have a higher propensity for engaging in political violence. It also found that providing access to a more peaceful, yet still exciting political group helps reduce this effect.

While the experimental method can be a valuable tool for learning more about psychology and its impacts, it also comes with a few pitfalls.

Experiments may produce artificial results, which are difficult to apply to real-world situations. Similarly, researcher bias can impact the data collected. Results may not be able to be reproduced, meaning the results have low reliability .

Since humans are unpredictable and their behavior can be subjective, it can be hard to measure responses in an experiment. In addition, political pressure may alter the results. The subjects may not be a good representation of the population, or groups used may not be comparable.

And finally, since researchers are human too, results may be degraded due to human error.

What This Means For You

Every psychological research method has its pros and cons. The experimental method can help establish cause and effect, and it's also beneficial when research funds are limited or time is of the essence.

At the same time, it's essential to be aware of this method's pitfalls, such as how biases can affect the results or the potential for low reliability. Keeping these in mind can help you review and assess research studies more accurately, giving you a better idea of whether the results can be trusted or have limitations.

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Schweizer M, Braun B, Milstone A. Research methods in healthcare epidemiology and antimicrobial stewardship — quasi-experimental designs . Infect Control Hosp Epidemiol . 2016;37(10):1135-1140. doi:10.1017/ice.2016.117

Glass A, Kang M. Dividing attention in the classroom reduces exam performance . Educ Psychol . 2019;39(3):395-408. doi:10.1080/01443410.2018.1489046

Keskin M, Ooms K, Dogru AO, De Maeyer P. Exploring the cognitive load of expert and novice map users using EEG and eye tracking . ISPRS Int J Geo-Inf . 2020;9(7):429. doi:10.3390.ijgi9070429

Ho A, Hancock J, Miner A. Psychological, relational, and emotional effects of self-disclosure after conversations with a chatbot . J Commun . 2018;68(4):712-733. doi:10.1093/joc/jqy026

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By Kendra Cherry, MSEd Kendra Cherry, MS, is a psychosocial rehabilitation specialist, psychology educator, and author of the "Everything Psychology Book."

July 1, 2020

14 min read

The Biggest Psychological Experiment in History Is Running Now

What can the pandemic teach us about how people respond to adversity?

By Lydia Denworth

Bernell Grier, who leads a community development corporation in Brooklyn, N.Y., is helping black people affected by the pandemic.

T he impact of COVID-19 on the physical health of the world’s citizens has been extraordinary. By April 2021 there were almost 130 million cases spread across more than 190 countries. The pandemic’s effect on mental health could be even more far-reaching. At one point roughly one third of the planet’s population was under orders to stay home. That means 2.6 billion people—more than were alive during World War II—were experiencing the emotional and financial reverberations of this new coronavirus. “[The lockdown] is arguably the largest psychological experiment ever conducted,” wrote health psychologist Elke Van Hoof of Free University of Brussels-VUB in Belgium. The results of this unwitting experiment are only beginning to be calculated.

The science of resilience, which investigates how people weather adversity, offers some clues. A resilient individual, wrote Harvard University psychiatrist George Vaillant, resembles a twig with a fresh, green living core. “When twisted out of shape, such a twig bends, but it does not break; instead it springs back and continues growing.” The metaphor describes a surprising number of people: As many as two thirds of individuals recover from difficult experiences without prolonged psychological effects, even when they have lived through events such as violent crime or being a prisoner of war. Some even go on to grow and learn from what happened to them. But the other third suffers real psychological distress—some people for a few months, others for years.

Even if most individuals prove resilient, the toll of the COVID-19 disruptions and the sheer numbers involved have experts warning of a mental illness “tsunami.” People face a multiple wallop: the threat of disease, loneliness of isolation, loss of loved ones, repercussions of job loss and ongoing uncertainty about when the pandemic will end. Depression, anxiety and post-traumatic stress will undoubtedly follow for some. Mental health hotlines have reported surges in calls, and early surveys found high levels of concern. “This pandemic just ticks all the boxes in terms of the kinds of stressors that are going to be difficult,” says psychologist Anita DeLongis of the University of British Columbia, who studies psychosocial responses to disease. The deaths by suicide of health care professionals who had been on the medical front lines are powerful reminders of the risks.

Individual resilience is further complicated by the fact that this pandemic has not affected each person in the same way. For all that is shared—the coronavirus has struck every level of society and left few lives unchanged—there has been tremendous variation in the disruption and devastation experienced. Consider Brooklyn, just one borough in hard-hit New York City. Residents who started 2020 living or working within a few miles of one another have very different stories of illness, loss and navigating the challenges of social distancing. How quickly and how well individuals, businesses and organizations recover will depend on the jobs, insurance and health they had when this started, on whether they have endured hassle or heartbreak, and on whether they can tap financial resources and social support.

The pandemic has laid bare the inequities in the American health care system and economic safety net. Black and Latino Americans are dying at much higher rates than white Americans. “When we talk about preexisting conditions, it isn’t just if I’m obese; it’s our society’s preexisting condition,” says medical anthropologist Carol Worthman of Emory University, an expert in global mental health.

Fortunately, the unprecedented pandemic is leading to unprecedented science not just in virology but on mental health and resilience. Behavioral scientists are measuring the psychological toll in real time and striving to identify what helps people cope. Unlike, say, the September 11 terrorist attacks or Hurricane Katrina, which occurred over a finite period even though their effects were drawn out, the open-ended time frame for COVID allows for new kinds of longitudinal studies and research directions. The sudden mass switch to virtual forms of working and socializing is expected to jump-start more nuanced investigations into what makes social interaction satisfying—or stultifying. If researchers meet the challenge of COVID, says psychiatrist Dennis Charney of the Icahn School of Medicine at Mount Sinai, “there will be a whole new science of resilience. We could learn how to help people become more resilient before these things happen.”

Bend but Don’t Break

Rafael Hasid arrived in New York City from his native Israel in 2000 to attend the French Culinary Institute. In 2005 he opened a restaurant called Miriam in Brooklyn that became a neighborhood favorite. In the first weeks of March 2020, Hasid could see what was coming. “I was following the news in Israel,” he says. “We were two weeks behind in every respect. I was saying, ‘This is going to happen here.’” When Miriam’s popular weekend brunch attracted a third of the usual crowd, Hasid did not spend much time wondering what to do: he gave away all of the restaurant’s perishable food to the neighbors. By the time the city required all restaurants to shut down, Miriam had already closed.

Faced with potentially traumatic events, “about 65 percent of people are going to show minimal psychological symptoms,” says clinical psychologist George Bonanno of Teachers College at Columbia University. Bonanno, who is an expert on resiliency, studies the aftermath of hurricanes, terrorist attacks, life-threatening injuries and epidemics such as the 2003 SARS outbreak. His research and that of others consistently shows three common psychological responses to hardship. Two thirds of people follow a resilience trajectory and maintain relatively stable psychological and physical health. About 25 percent struggle temporarily with psychopathology such as depression or post-traumatic stress disorder and then recover—a pattern known as the recovery trajectory. And 10 percent suffer lasting psychological distress. These results hold true across diverse populations and socioeconomic statuses. “We’re talking about everybody,” Bonanno says. On the other hand, the risk of psychiatric disorders is twice as high for people on the lowest economic rungs.

But the mental health effects of a crisis so sweeping and insidious may not adhere to this paradigm. Studies show that strict quarantine can lead to negative psychological effects such as PTSD, although few of us have been under true quarantine, which refers to isolating after a possible exposure to infection. Instead much of the world is living with restrictions that Bonanno suspects amount to something more like managing constant stress. “This is the first time in living history we’ve had a global lockdown that’s gone on for such a long time,” says epidemiologist Daisy Fancourt of University College London. “We simply don’t know how people are going to react to this.”

The potential scope of the impact is considerable. “This is different from other forms of stress because it’s not just one domain of your life,” says health psychologist Nancy Sin of the University of British Columbia. “People are dealing with relationship or family challenges, with financial and work challenges, with health.”

Early reports were showing clear effects. The first nationwide large-scale survey in China, where the crisis hit earliest, found that almost 35 percent reported psychological distress. In the U.S., rising fear and anxiety about COVID have been found in people who already suffer from anxiety. Another study captured worrisome findings in older adults. This is surprising because previous research shows that, for the most part, older adults have better emotional well-being. “During this pandemic, older adults don’t have those age-related strengths in emotions that we would typically expect,” says Sin, who studies aging and is collaborating with DeLongis in an ongoing COVID-19 study of 64,000 individuals worldwide. “They are reporting just as much stress as middle-aged and younger people.”

Sin is still analyzing the causes of the stress but suspects it is caused by older adults’ higher likelihood of getting sick and of losing loved ones. Older people are coping with their stress better than younger people, however, and reporting less depression or anxiety. They may be benefiting from the perspective that comes with having lived through more than younger people, Sin says. Adults older than 65 have also had more time to develop skills for dealing with stress, and many have retired and so are less likely to be concerned about work.

Fancourt began a study in mid-March 2020 that at one point grew to include more than 90,000 U.K. residents. It is tracking depression, anxiety, stress and loneliness week by week. “We need to know in real time what’s happening,” Fancourt says. Six weeks in, they found that levels of depression were significantly higher than before the pandemic.

Generally, those with previously diagnosed mental health illnesses, those who live alone and younger people were reporting the highest levels of depression and anxiety. On the positive side, there was a slight decrease in anxiety levels once the lockdown was declared. “Uncertainty tends to make things worse,” Fancourt says. Some are frozen by not knowing what is to come, whereas others find ways to carry on.

After Hasid’s restaurant had been closed for three weeks, he had not yet received any of the government payments meant to protect small businesses. While his situation was rife with uncertainty, “I was thinking that we have to continue creating business for ourselves,” he says. When a few customers e-mailed to inquire if he would consider catering their Passover seders, Hasid developed a prix fixe holiday menu for delivery. Before the pandemic, Hasid was planning to open a delicatessen that would be located in an adjacent storefront. Instead of renovating the new space, he opened the deli inside the restaurant. His biggest worry was whether employees would feel safe. To reassure them, in addition to social distancing, he requires masks and gloves and has someone come in to bleach the restaurant morning and night. Hasid also looked into other sanitizing strategies involving blowers and alcohol that he heard had been used in Singapore.

Hasid recognizes that his ability to adapt is not something every business can do, especially many restaurants that run on tight margins. The new operation used minimal staff, but Hasid continued to pay—out of his own pocket—any employees who were not able to get through to unemployment. Serving food via delivery brings in less than a third of Miriam’s former income, but he says it is better than nothing. Last year the restaurant also began preparing a weekly meal for a local hospital. “It is not a money maker, but it’s the least we can do.” Hasid is pleased with Miriam’s reinvention and optimistic that the restaurant will ultimately survive. “We are in a much better situation than a lot of other places in New York,” he says.

When Tom Inck ( top right ) fell ill with COVID-19, his wife, Wendy Blattner ( standing ), cared for him while managing upheavals in her business and their daughters' lives. Credit: Ethan Hill

The Components of Coping

When Brooklyn resident Tom Inck developed a persistent fever and dry cough in the middle of March 2020, the psychotherapist and management consultant feared he had COVID. Because of the shortage of tests at the time, Inck’s doctor first screened for every other known virus (Inck paid for the test panel). Then doctor and patient met on the streets of Manhattan. Standing on Madison Avenue in full protective equipment, the doctor administered the test, which came back positive six days later.

Successfully coping in a crisis means continuing to function and engaging in day-to-day activities. One must solve problems (whether that means getting groceries or a virus test), regulate emotions and manage relationships. There are factors that predict resilience such as optimism, the ability to keep perspective, strong social support and flexible thinking. People who believe they can cope do, in fact, tend to cope better.

During nine days of isolation in a spare room, Inck filled the time with meditating and reading. In some ways, things were harder for his wife, Wendy Blattner, who was managing her husband’s care, the transition of her marketing agency to remote work, and the emotions of the couple’s two college-aged daughters, who were upset at the loss of their semesters and anxious about their father. Blattner left meals outside her husband’s door and got up every three hours throughout the night to record his temperature and blood oxygen level. She was scared but resolute. “I felt like he had excellent care, even though it was remote, and that I had the resources within myself and the support I needed,” she says. “That’s what I told my kids and what I told myself—that it might get rough, but it was going to be okay.”

Most people’s coping skills can be strengthened. Several of the new studies are designed to identify successful strategies that buffer the effects of the stress. So far, Fancourt says, people are encouraged to follow classic mental health strategies: getting enough sleep, observing a routine, exercising, eating well and maintaining strong social connections. Spending time on projects, even small ones, that provide a sense of purpose helps.

In previous work, DeLongis has shown that those who are high in empathy are more likely to engage in appropriate health behaviors such as social distancing and to have better mental health outcomes than people who are low in empathy. But her earlier studies of diseases such as SARS and West Nile were cross-sectional and captured only a moment in time. Her COVID-19 study followed people’s behavior and attitudes for months to capture changes in empathy and coping over time. “This isn’t just about a trait of empathy,” DeLongis says. Empathetic responses can be learned and encouraged with proper messaging, and her hunch was that increases or decreases in empathetic responding over weeks and months would be associated with shifts in health behaviors and coping mechanisms.

As part of DeLongis’s study, Sin asked people to record their daily activities and emotions for a week. In the early months of the pandemic, she says, the picture was “that life is really challenging, but people are finding ways to meet that challenge.” Many reported a great deal of positive social interactions, many of them remote. Older adults reported the highest levels of positive experiences in their daily lives, often through providing support to others.

It is striking that remote connections are proving satisfying. Previous research on the effects of digital technology and media focused on the association between time spent on screens and psychological well-being but revealed little about the worth of different kinds of online interaction. Now that the world is relying on the Internet to socialize, investigating those nuances is crucial. Should social media closely mimic face-to-face interaction, or can less intense forms of communication leave people feeling connected? We do not know yet, but it is likely those studies will now get funded when previously they weren’t. “I think we just skipped a decade of conversation in a month,” says psychologist Amy Orben of the University of Cambridge, who studies adolescent mental health and technology use.

Social media is a factor in other kinds of research as well. Psychologist Roxane Cohen Silver of the University of California, Irvine, is assessing the impact of media exposure on people’s well-being. “Those who consume a great deal of news about a community-wide crisis are more distressed,” she says. Computational social scientist Johannes Eichstaedt of Stanford University is combining large-scale analyses of Twitter with machine learning to capture levels of depression, loneliness and joy during the pandemic.

As Blattner feared, things did get rough for their family. On nights seven and eight, when Inck’s fever hovered around 103 and his blood oxygen levels dropped to 93, his doctor (via Zoom) said if the levels stayed there or got worse, Inck should go to the hospital. “I’m not going to have a patient who dies at home,” he said, a statement that alarmed the children. “The toughest thing for us was the fear,” Inck says. But Tylenol kept the fever in check, and short, shallow breaths kept Inck’s blood oxygen level in the safety zone. After 10 days, he began to feel better.

The experience left Inck grateful and energized. He threw himself back into work counseling others who were sick and signed up to be a plasma donor for critical patients. But, unlike others who recovered, he did not initially venture out much. “The world felt like a vulnerable place,” he says.

Restaurant owner Rafael Hasid rapidly reinvented his business for takeout and delivery but was paying employees out of his own pocket. Credit: Ethan Hill

Society’s Preexisting Conditions

Even those brimming with personal resilience need outside help if they face challenges on multiple fronts. As executive director of IMPACCT Brooklyn, a community development corporation that serves the historically Black neighborhoods of Brooklyn, Bernell K. Grier sees just how hard the pandemic has hit the African-American community. “Daily, I’m hearing of people who are either COVID-positive, recovering from it or have died from it,” she says. Three of those deaths occurred in apartments that Grier manages and required her to organize deep-cleaning services. Still, she pressed on. “Seniors are fearful of going out, fearful of anyone coming to their front door,” Grier says. “They also are not tech-savvy. A lot of things where they’re being told to go on the computer, they need someone to hold their hand and help them through the process.”

The pandemic, Fancourt says, “is going to exacerbate the social gradient that we’re used to seeing across society. It’s crucial that [people] have interventions at a national level that can support [them].” In the U.K., such interventions include the National Health Service and a furlough program that pays up to 80 percent of the salaries of millions of Britons who could not work because of the pandemic. In the U.S., paycheck-protection packages and unemployment exist but proved difficult to access quickly.

Grier’s organization provides a variety of services around housing, small business advocacy, and interaction with financial and government institutions. As soon as the pandemic hit, her staff distributed information about public health and economic resources. They introduced webinars to help businesses apply for loans. As of late April 2020, “none of the ones that we helped got anything,” Grier says. “It’s not reaching our businesses.” Only 70 percent of Grier’s tenants were able to pay rent in April 2020. “We still have to pay the supers, the porters, the heat and electricity, the taxes and everything else,” Grier says. “It’s a domino effect. If the residents can’t pay, we can’t pay.”

Worthman, the Emory anthropologist, says the ability to cope with the pandemic’s reverberations is not just an individual issue but a societal one. It is also an opportunity. “People have pointed to periods of disaster in American history, after World War I and the Depression, that led to real structural change that benefited people.”

Grier is advocating for positive change for her community. In her talks with public health and elected officials, she points out disparities such as the fact that the first test centers were not located in poor neighborhoods. “This is a spotlight on what has existed for too long,” she says. “When you’re looking at [solutions], make sure that income equality and a racial-equity lens is a filter for everything that’s put in place.” As Brooklyn reemerges from social isolation, Grier knows the critical role groups like hers play. “We will continue to be here to be that liaison, that credit counselor, that navigator.”

Cultivating resilience though community support appears to be more important than ever. As a school nurse in Brooklyn, Marilyn Howard, who immigrated from Guyana as a teenager, worked through the early weeks of March 2020 until the public schools closed. She got sick the day after she left work. It took 10 days to get the test results that confirmed she had COVID. By then Howard thought she was on the road to recovery. But on Saturday, April 4, she awoke with labored breathing that rapidly worsened. Her brother Nigel Howard, with whom she shared an apartment, called an ambulance. But April 4 was near the peak of the pandemic in Brooklyn, and there was no ambulance available. Nigel drove them to the nearest hospital, but Marilyn’s breathing deteriorated on the way. Less than a minute before they arrived, her heart stopped, and she could not be revived. She was 53.

“A couple of simple things could have saved my sister’s life,” says Haslyn Howard, the youngest of Marilyn’s five brothers. If schools had closed earlier or her colleague could have taken a sick day, she might not have gotten sick. If someone had recommended a pulse oximeter, she would have known to go to the hospital sooner. If an ambulance had been available.... The Howard brothers arranged a viewing at a Long Island funeral home to provide some closure. Haslyn permitted only three people in the room at a time, but a simultaneous virtual service allowed more than 250 people to celebrate Marilyn’s life.

Nigel later tested positive for COVID and isolated at home. “My brothers and I are in the initial phases of trying to plan an organization that targets efforts to help the Black and brown community, poor communities, address some of these [issues] on a local and tangible level,” Haslyn said soon after losing his sister. It is something they can do in her memory that would have made her proud. “That’s one of the ways that we’re coping,” he adds. “How do we turn tragedy into triumph?”