famous case studies in psychology

15 Famous Experiments and Case Studies in Psychology

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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26 Famous Psychology Case Studies

Many famous psychology case studies have been debunked. In this article, I will outline those that have withstood the test of time and those that have not. Here are the case studies:

Phineas Gage – Physician John Martyn Harlow
Anna O. – Breuer & Freud (1895)
Cleckley ‘s (1941) case studies of psychopathy ( The Mask of Sanity ) and multiple personality disorder ( The Three Faces of Eve ) (1957)
Little Hans – Freud
Rat Man – Freud
John/Joan case – John Money
Genie (feral child)
Piaget’s studies
Rosenthal’s book on the murder of Kitty Genovese The Bystander Effect – (Debunked)
Rosenhan’s experiment – David Rosenhan – (Debunked)
Washoe (sign language)
Patient H.M.
Lev Zasetsky – A.R. Luria
Solomon Shereshevsky – A.R. Luria
When Prophecy Fails [3] – by Leon Festinger , Henry Riecken , and Stanley Schachter
The Marshmallow Experiment – Walter Mischel
Jill Price – Elizabeth Parker; Larry Cahill; and James McGaugh.
Halo Effect Experiment – Edward Thorndike 1977
Bobo Doll Experiment , 1961, 1963
The Asch Conformity Study , 1951 – Solomon Asch
Milgram experiment , 1963 – Stanley Milgram
Stanford Prison Experiment , 1971- Philip Zimbardo – (Debunked)
The Learned Helplessness Experiment , 1965 – Martin Seligman
The Little Albert experiment, 1920 – John B. Watson and Rosalie Rayner Johns
Anna O – Freud
Czech Twins – Koluchova

The Top 10 Cases In The History Of Psychology

By MS Broudy
Published October 11, 2019
Last Updated November 13, 2023
Read Time 8 mins

Posted October 2019 by M.S. Broudy, B.A. English, B.A. Psychology; M.A. Social Psychology; Ph.D. Psychology; 6 updates since. Reading time: 8 min. Reading level: Grade 8+. Questions on the top cases in psychology history? Email Toni at: [email protected] .

Nothing captivates us more than the human mind. We are constantly attempting to understand the origins of behavior and the intricate workings of the brain. Throughout our history, there have been particular people whose story is so astonishing that they have remained a source of constant curiosity and learning. Here are 10 extraordinary cases from the realm of psychology that continue to fascinate.

Phineas Gage

In 1848, Phineas Gage was working as a foreman on a railroad crew in Vermont. While he was using a tamping iron to pack some explosive powder, the powder exploded, driving the iron through his head. Amazingly, he survived but friends noted that he no longer acted like the same person. He had limited intellectual ability and there were acute changes in his personality. He spewed profanity, was highly impulsive and showed little regard for other people. The change in Gage’s personality is consistent with damage to the orbitofrontal cortex of his frontal lobe, which impacts affect and emotion. It was one of the first cases to show a link between the brain and personality, in addition to cognitive functions.

Louis Victor Leborgne (Tan)

Similar to what H.M. did for memory, the case of Louis Victor Leborgne made significant contributions to the study of language production and comprehension. At age 30, he was admitted to a Paris hospital after losing his ability to speak. He could only say the word “tan” and was later called by that name in recalling his case. Despite his inability to speak, his cognitive functions appeared intact. Leborgne could comprehend what was being said to him and retained his intelligence. In 1861 he met physician Paul Broca after developing Gangrene. Upon Leborgne’s death, Broca examined his brain and found a lesion in his left frontal lobe. Due to Leborgne’s language, Broca postulated that this area of the brain was responsible for speech production. This area of the brain has become known as Broca’s area (Leborgne’s condition is called Broca’s aphasia) and is one of the most significant findings in the neurological study of speech.

Bertha Pappenheim (Anna O)

Bertha Pappenheim is thought to be the first person to undergo psychotherapy. Although her case is usually associated with the work of Sigmund Freud, it was his colleague, Joseph Breuer, who was initially her treating physician. Pappenheim suffered from “hysteria” as well as hallucinations and various ailments. Despite some records noting that she was cured by talk therapy, certain historians report that her improvements were temporary and she was never cured. Although Freud never met Pappenheim, he often publicly referred to Anna O. as the first recipient of the “talking cure” and said it was her case that was responsible for the birth of psychoanalysis.

Little Albert

In 1920, psychologist John Watson and his future wife, Rosalind Rayner, experimented on an infant to prove the theory of classical conditioning. They called the baby “Albert B.” And the case became known as the “Little Albert” experiment. Watson and Rayner paired a white rat and other objects with a loud noise to condition a fear response in Albert. The experiment showed that people can be conditioned to have emotional responses to a previously neutral object and that the response can be generalized to other stimuli. One of the most important conclusions drawn from the experiment is that early childhood experiences can influence later emotional development. Of course, scaring a baby for scientific purposes is now seen as highly unethical. The Little Albert experiment has become known as much for its lack of ethical boundaries as it has for its contributions to behavioral psychology.

Henry Gustav Molaison (H.M.)

In 1955, Henry Gustav Molaison (known frequently in the literature as H.M.) had brain surgery to cure himself of debilitating epilepsy. The surgery involved removing both halves of the hippocampus. Although the operation did relieve most of his seizures, it had an unintended effect: he could no longer form short-term memories. H.M. also suffered some retrograde amnesia, losing memories for 11 years before the operation. Otherwise, his long-term memory was intact. Because the surgery was so precise, it perfectly exhibited the role of the hippocampus in memory creation. H.M. was studied for the rest of his life and, upon his death, donated his brain to science. It would not be a stretch to say that he contributed more to the study of memory than any one subject.

Kitty Genovese

In 1964, Kitty Genovese was murdered on the street in Queens, New York. At the time, it was reported that a multitude of people saw her get killed and did nothing about it. Ever since, this event has been promoted as a prime example of the Bystander Effect: the more people that witness an event, the less likely they are to do something about it. Later investigations found that there were some discrepancies in the reporting and a couple of people at the scene may have indeed tried to report the crime. Although the basic principle of the Bystander Effect has held up over the past 50 years, the real legacy of the case is the research and activism it has inspired. The Genovese case has spurred an immense amount of psychological study across different areas, including forensic psychology and prosocial behavior. Additionally, it impacted the creation of victim services, Good Samaritan laws, and the 911 emergency call system.

Chris Costner Sizemore

You may not know the name Chris Costner Sizemore but you may have heard about her life in the movie “The Three Faces of Eve”. Sizemore’s case is one of the first and most famous involving multiple personalities, which is now known as Dissociative Identity Disorder. Until the publicity of her case, the possibility that people could have multiple personalities was, for most, a fantastical notion rather than a reality. In addition, Sizemore’s case shines a light on severe psychological consequences of early childhood trauma. Sizemore believes her different personalities developed as a way to cope with certain disturbing experiences she had when she was younger. After three of her personalities were publicized in the movie, she says she continued to experience other personalities throughout her life.

Genie was brought up in a house of extreme abuse and neglect. For most of her first 13 years, she was strapped onto a chair in a single room with almost no human interaction. When Genie was found, she possessed the development level of a one-year-old. She worked with numerous professionals and learned to develop motor skills and how to comprehend language. She also obtained a decent vocabulary, but could not catch up on her grammatical skills. It seemed Genie had missed a critical period of language development, proving you cannot learn grammatical language later in life. In addition to speech development, the case of Genie exhibits the effects of severe abuse and neglect. It also illustrates the great resiliency of human beings to overcome deprivation.

Kim Peek was the inspiration for Dustin Hoffman’s character in the movie Rain Man. Although many people believe he was autistic, he was a non-autistic savant, with exceptional mental abilities. His memory and capacity to perform certain mathematical calculations were nothing short of astounding. An MRI exam showed that Peek was lacking the corpus callosum, the part of the brain that connects the two hemispheres. It is thought that this brain abnormality contributed to his special abilities. Despite his uniqueness, his brain was not his biggest contribution to psychology. Ironically, the misconception of his autism helped to raise the profile of the little-known disorder into the mainstream.

David Reimer (John/Joan Case)

David Reimer was born a boy but his penis was castrated by accident during a circumcision procedure. Instead of trying to reconstruct his penis, it was recommended by a doctor, John Money, that he be brought up as a girl. Money believed that gender was a choice and could override any natural inclination. As a result, when he was 17 months old, David underwent surgery and became Brenda Reimer. Despite Money’s assurances that the process was a success, David’s parents could tell that he was not happy as a girl. Eventually, when he was 14, his parents told him he was born a boy and David elected to reverse the gender reassignment process to become male again. David’s story has become a cautionary tale. He committed suicide at age 38. He spent much of his life campaigning against gender assignment surgery being forced upon children without consent. His case is one of the most high profile indications that gender identity is not a choice, attempting to undo the damage caused by John Money’s false assertions.

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7 Famous Psychology Experiments

Picture of a piece of art used for psychological 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.

Is a Psychology Degree Right for You?

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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.

Five Landmark Psychology Case Studies You Should Know About

The psychology case study is one of the oldest research methods in the discipline. One individual, sometimes with an abnormality, is studied in great depth. Psychology, as a science, seeks to discern universal truths, so the study of atypical individuals must be done with caution. These unrepresentative studies, though, suggest avenues for future research. Some of psychology’s most rewarding findings have been influenced by initial case studies. These findings were then corroborated by representative, rigorous research methods, namely the experiment.

1. Phineas Gage

One of the few portraits of Phineas Gage, holding the same tampering iron that damaged his brain.

On a day in 1848, Phineas Gage, a mild-mannered railroad worker, used a tampering iron to pack gunpowder into a rock. But a spark accidentally detonated the gunpowder, causing the rod to shoot up through his left cheek and the top of his skull. His left frontal lobe was severely damaged, but he survived. In fact, he immediately sat up and was able to talk. But Gage’s personality dramatically changed. He became short-tempered, rude, impulsive, and immoral. Friends said he was “no longer Gage.” He lost his job as a foreman and spent some time traveling the road as a circus attraction.

Almost all of what we know about Gauge is from published accounts by Dr. John Martyn Harlow. For a case so often cited, relatively little is known about the Gage’s, namely his life before and after the accident. The extent of Gage’s personality changes may have been inaccurate. Later evidence show that Gauge, for the last decade of his life, worked the same job in two locations. This is not consistent with the image of Gage as a capricious, emotionless drifter.

Nonetheless, Gage’s early case study illustrated the significance of association areas, the areas of the cerebral cortex involved in the higher mental functions (thinking, learning, remembering, etc.) that make us truly human. It was also one of the first cases that showed a neurological basis for personality and behavior. More recent studies in psychology look into these possible connections between morality, emotion, and the brain. But they owe a debt of gratitude to Phineas Gage.

2. “Genie,” the feral child

Genie after being rescued, malnourished and unable to properly walk.

Genie is a relatively recent example of a feral child. Feral children are humans raised in social isolation, experiencing little or no human contact in their lives. Feral children are typically the result of either child abandonment or abuse. Due to malnourishment and lack of mental stimulation, feral children never fully cognitively develop.

Genie was such a child. Found in 1970 at the age of 13, Genie had spent most of her life confined in a bedroom, strapped to a potty chair. Her father had believed she was mentally retarded, so he took steps to “protect her.” He beat her every time she made a sound. Her physical and mental development was stunted, and she never learned to speak or walk properly.

After she was found and properly cared for, Genie progressed, learning to communicate nonverbally with her caretakers. But as funds and research interest dried up, she went through a series of foster homes and today, at age 54, is psychologically confined. She has regressed, reverting to her coping mechanism of silence.

Genie’s case contributed significantly to psychological and linguistic theory. It showed the significance of enculturation in acquiring social skills. From a young age, mental stimulation is needed for motor and sensory development. Without mental stimulation, neurogenesis is hindered. Feral children like Genie support the “critical period hypothesis” of language acquisition. After the first few years of life (a critical developmental period), learning a language becomes more difficult (almost impossible) for a human child. Missing this window. Genie never learned to speak a grammatically correct verbal language.

A portrait of H.M., Henry Molaison, in 1953.

Henry Gustav Molaison was perhaps the most important patient in the history of neuroscience. At the age of 9, a bicycle accident damaged his brain and caused him to suffer from seizures. In 1953, as a last resort for curing these convulsions, surgeons removed slivers of tissue from his hippocampus, an area we know now (thanks to HM) is critical in the formation of long-term memories. H.M. was left with severe anterograde amnesia. He basically lived in the past, unable to create new memories. Even his past memories were clouded by mild retrograde amnesia, leaving him only able to remember the gists of childhood events.

Dr. Brenda Milner’s study of H.M. paved the way for the study of human memory and memory disorders. In repeated trials, Dr. Milner told H.M. to perform a simple motor task, such as outlining a five-point star. Each time, H.M. recognized it as an entirely new experience. Yet he became more proficient at the task with practice. H.M. could be classically conditioned, learning things without the awareness of having learned them.

Thanks to Dr. Milner’s study, we know that memory consists of two systems that operate together. One is explicit, or declarative. It involves facts we know and can declare. It of course depends on the hippocampus, which H.M. had partially removed. The other is retention that is independent of conscious recollection: subconscious learning of motor functions. This finding revolutionized the understanding of memory and the neurological mechanisms behind it.

4. Jill Price

Jill Price, who published her story in a 2008 memoir.

Jill Price is one of the very few patients with hyperthymesia, an incredible memory that allows her to remember numerous obscure aspects of her life in incredible detail. She can, for example, remember what she had for dinner 20 years ago, on an ordinary August afternoon. This ability has caused her significant emotional trauma due to her remembrance of every derogatory remark or traumatic event in her life. Jill Price is still participating in psychological studies that hope to shed light on her condition.

Recent memory tests , however, show that Jill Price isn’t exactly a memory whiz, and that her abilities have been blown out of proportion. Mrs. Price cannot memorize a new list of words with great accuracy. Her memory is, in many respects, average. She can remember famous dates and names, but only if she finds them somehow relevant to herself. One of the key, previously underestimated, elements of Mrs. Price’s condition is her OCD-like symptoms. She hoards and feels a need to organize her life. Perhaps most significantly, she spends much of her time constantly thinking about herself and events in her life, elaborately encoding them into her memory.

All of this evidence, along with brain scans that show enlarged regions consistent with an OCD patient, suggests that Jill Price has a rare offshoot of Obsessive-compulsive disorder, and that her memories are a result of obsession. Only future research can corroborate or disprove this promising theory.

5. The John/John Case

David Reimer, formerly Brenda Reimer.

Dr. John Money was an influential sexologist that pioneered the theory of gender neutrality. He argued that, in the classic nature vs. nurture debate, nurture fully determined gender. Gender was supposedly malleable and determined in the first few years of cognitive development. Once the “gender gate” closed, a human’s gender identity was relatively stable.

The Reimer twins were circumcised at 6 months old. Unfortunately, the electrical equipment used in the circumcision malfunctioned, severely damaging Bruce Reimer’s penis. A few months later, his parents wrote to Dr. Money seeking help. Under his advice, Bruce Reimer was sexually reassigned in 1967. He was castrated and a vulva was surgically created. His parents attempted to raise him as a girl, Brenda.

In infrequent annual follow-ups, Brenda’s parents lied about the surgery’s success. Dr. Money then used this case study as proof of his controversial gender theory. The case revolutionized the way psychologists viewed gender, which apparently had no biological basis.

Growing up, Brenda acted masculine and was teased constantly at school. She could not socialize as a girl. Contrary to Dr. Money’s reports, she did not identify as female. At age 13, Brenda’s parents told her about her past. Brenda, relieved, then fully identified as a male, taking the name “David.” She underwent gender reassignment surgery and lived the rest of her life as a male.

Dr. Money failed to follow up with his patient because doing so would have shattered his influential theory. But David Reimer finally went public in 1997, telling his story with the aid of Dr. Milton Diamond, a noted rival of Dr. Money. David Reimer, who had suffered from depression throughout his life, committed suicide seven years later.

This landmark case study was frequently cited by the feminist movement, anthropologists, developmental psychologists and biologists, and psychiatrists to argue that nurture, not nature, explained all gender differences. Dr. Money’s theory became widely accepted. Intersex children, in accordance to this study’s findings, were regularly sexually reassigned.

The impact of this controversy is still being felt. The one case study that backed Dr. Money’s theory perfectly was unscientific, misleading, and unethical. Dr. Money’s legacy is posthumously harmed, and his theory is once again with valid proof.

Proceeding With Scientific Caution and Skepticism

As we’ve seen, case studies can be incredibly informative, despite dealing with a few atypical individuals. But the use of case studies in psychology must be done both carefully and ethically.

The John/Joan case was discussed last because it basically shows us everything the full range of a case study’s effects, both positive and negative. Case studies can provide opportunities for experimentation that cannot be artificially created. Two twin boys — one “normal” male and one to be raised as a female — gave Dr. Money a chance to put his theory to the test.

When a case study is correct, it can be used as definitive proof of one theory or disproof of another. But the above case study shows us that, when flawed, these studies can lead to misleading, incomplete, or downright false information. Not only are they not representative, the scientists studying them can be biased. Dr. Money fell in love with his own theory and refused to see any contrary evidence as reliable. A psychologist must be explicit about one’s biases when performing a case study, and avoid becoming too emotionally invested in a particular viewpoint.

Ethical Concerns

Lastly, the use of case studies sometimes raises serious ethical concerns. A patient like H.M. was agreeable, otherwise healthy, and enjoyed participating in studies. But what about the others?

– Genie was treated well initially. But when it became clear that there could be no “Miracle Worker” to help her learn to fully verbally communicate, the scientific community lost hope and interest. Funding dried up. Genie’s foster parents, no longer generating scientific data, passed her on to another foster home. Genie was clearly exploited by her caretakers for their own means, which is evident in the custody battles over her (before, but not after, there was scientific funding available to study her). A unique opportunity to study an atypical individual can bring out the worst in psychologists. In focusing on gathering data, they seem to like Zambardo in the infamous Stanford prison experiment, forget that they are dealing with real people, sometimes facing serious emotional trauma.

– Jill Price’s condition had been exaggerated by early studies that ignored the OCD symptoms of her condition. If we all spent as much time as she did obsessing over the details of our personal lives, couldn’t we all have such a remarkable memory? By promoting her as a “superwoman,” perhaps we have enabled her condition and glamorized it, instead of allowing her to properly focus on undergoing therapy. Perhaps though, future studies will shed light on hyperthymesia as a form of OCD, leading to improved quality of life for individuals suffering from this rare disorder.

Lastly, we come to the David Reimer case, which is a recent reminder to psychologists about ethical concerns. Dr. Money’s scientific follow-ups were inappropriate. But the initial decision to perform the surgery was perhaps most disturbing. In retrospect, we know that it didn’t work out. It obviously caused a human being to undergo unnecessary trauma, and likely contributed to David Reimer’s sever depression, which ended in his 2004 suicide.

Should Dr. Money have done the study? One of the things that psychology has undoubtedly proved is that hindsight is 20/20. Perhaps a more interesting question is this: What if it worked? What if Brenda Reimer lived life as a healthy woman? Would that have been moral justification for such an experiment? What is the appropriate way for a parent to treat an intersex child? Should they choose a gender, or let their child choose it themselves later on life?

These are all questions that fall into a moral gray area that nobody, even scientists, can confidently navigate. For the many ethical concerns raised by case studies, we unfortunately have more questions than answers.

Video Resources

Phineas Gage – Personality change as a result of a head injury:

Genie: Nova’s Secret of the Wild Child special:

Developmental molecular biologist and author John Medina, on what we learned from HM:

A revealing 20/20 interview with Jill Price:

An news program clip on the John/John controversy:

Carey, B. (2008, December 04). H. M., an Unforgettable Amnesiac, Dies at 82 . Retrieved May 01, 2011, from http://www.nytimes.com/2008/12/05/us/05hm.html

David Reimer: David Reimer The boy who lived as a girl . (2004, May 10). Retrieved May 01, 2011, from http://www.cbc.ca/news/background/reimer/

Dr Money and the Boy with No Penis . (n.d.). Retrieved May 01, 2011, from http://www.bbc.co.uk/sn/tvradio/programmes/horizon/dr_money_prog_summary.shtml

Gray, K., & Escherich, K. (2008, May 9). Woman Who Can’t Forget Amazes Doctors . Retrieved May 01, 2011, from http://abcnews.go.com/Health/story?id=4813052

James, S. D. (2008, May 07). Wild Child Speechless After Tortured Life . Retrieved May 01, 2011, from http://abcnews.go.com/Health/story?id=4804490

Macmillan, M., Macmillan, I., Macmillan, M., & Lena, M. L. (2009, July 30). Phineas Gage Information [Scholarly project]. In The Phineas Gage Information Page . Retrieved May 01, 2011, from http://www.deakin.edu.au/hmnbs/psychology/gagepage/

Marcus, G. (2009, March 23). Total Recall: The Woman Who Can’t Forget . Retrieved May 02, 2011, from http://www.wired.com/medtech/health/magazine/17-04/ff_perfectmemory?currentPage=all

Myers, D. G. (2010). Psychology . New York, NY.: Worth.

The Boy who was Turned into a Girl . (n.d.). Retrieved May 01, 2011, from http://www.bbc.co.uk/science/horizon/2000/boyturnedgirl.shtml

Copyright Notice

Some of the images used above may be subject to copyright. No infringement is intended by the use of these images. This blog post is for a course project and is not intended to gain page views (let alone commercial revenue) in any manner. If you have an issue with my use of the above images, please contact me at [email protected]

What are some of the most famous case studies in psychology?

Some of the most famous case studies in psychology include the case of Phineas Gage, who experienced severe personality changes after a brain injury . Another well-known case is that of Henry M., who lost his referential memory after a bilateral hippocampal ablation . The case of the journalist S. V. Shereshevsky, who had seemingly unlimited memory, is also widely recognized . Additionally, Kazdin's strategies for reducing threats to the validity of conclusions from case studies, Elliott, Fischer, and Rennie's development of methodological standards for research, and the Pragmatic Case Study (PCS) approach have contributed to the field of case study research in psychology . "Classic Case Studies in Psychology" is a collection of fascinating human stories that provide revealing insights into the human mind and behavior .

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