8 of the Most Classic Psychological Experiments - Explore Psychology (2023)

(Last Updated On: October 4, 2022)

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 the field 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.

Pavlov’s Dog Experiments

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

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 behaviorist 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.

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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

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 other participants. In reality, the other individuals in the room were actors who were following the instructions provided by the experimenters. 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 had a tendency 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 picked 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

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.

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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

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

While the cloth mother did not provide nourishment, the experiments demonstrated that the baby monkey’s 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

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

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 that resembles the shape of a bowling pin. When hit or kicked, the doll tips sideways and then returns to an upright position.

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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

In this infamous psychological 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 was 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.


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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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What is the most famous experiment in psychology? ›

Experiment Details: One of the most widely cited experiments in the field of psychology is the Stanford Prison Experiment in which psychology professor Philip Zimbardo set out to study the assumption of roles in a contrived situation.

What makes a classic study in psychology? ›

However, one quality that makes these studies genuine classics is that their details are well-known not just inside but also outside social psychology – not only by researchers in other academic disciplines (e.g., sociology, politics, economics, history), but also by journalists, social commentators, policy makers and ...

What is an example of a psychological experiment? ›

One experimental psychology research example would be to perform a study to look at whether sleep deprivation impairs performance on a driving test. The experimenter could control other variables that might influence the outcome, varying the amount of sleep participants get the night before.

What is the most important discovery in psychology? ›

Notice that most of the iceberg is submerged below the water line in this picture the water line

What are the top 10 experiments of all time? ›

Top 10 Beautiful Physics Experiments
  • Young's double-slit experiment applied to the interference of single electrons.
  • Galileo's experiment on falling bodies (1600s)
  • Millikan's oil-drop experiment (1910s)
  • Newton's decomposition of sunlight with a prism (1665-1666)
  • Young's light-interference experiment (1801)

Why is psychology so important? ›

Essentially, psychology helps people in large part because it can explain why people act the way they do. With this kind of professional insight, a psychologist can help people improve their decision making, stress management and behavior based on understanding past behavior to better predict future behavior.

What is classic experiment? ›


Experiments are designed to determine the presence or absence of causal relationships: whether a particular independent variable causes (influences, impacts, determines) a particular dependent variable.

What is experiment in psychology definition? ›

An experiment involves the manipulation of an independent variable, the measurement of a dependent variable, and the exposure of various participants to one or more of the conditions being studied.

What is classical experimental design? ›

Classic experimental design– uses random assignment, an experimental, a control group, pre-testing, and post-testing. Comparison group– a group in quasi-experimental designs that receives “treatment as usual” instead of no treatment.

What is experimental psychology essay? ›

Experimental psychology is a sub-discipline in psychology that focuses on understanding the human behavior resulted from life experience through research and experimental studies (“Career in Psychology,” n.d.). Therefore, experimental psychologists approve or disapprove psychological beliefs through research.

What are the 4 types of experimental research? ›

Four major design types with relevance to user research are experimental, quasi-experimental, correlational and single subject. These research designs proceed from a level of high validity and generalizability to ones with lower validity and generalizability.

How do I start learning psychology? ›

Today, there are plenty of great ways to learn more about the human mind and behavior such as taking a college course, signing up for a free online class, or self-studying using online resources.

Which course is best for psychology? ›

Here are the best Psychology courses at the master's level/after graduation:
  • MSc Clinical Psychology.
  • Master of Psychology.
  • MA Counselling Psychology.
  • MSc Behavioural Science.
  • MSc Developmental Psychopathology.
  • MA Developmental Psychology (Research Methods)
  • MA Ed Curriculum, Instructional and Educational Psychology.

Is psychology hard to study? ›

Psychology is one of the more difficult degrees and many of your assignments will require you to cite your sources and will require you to back up a lot of the arguments that you have.

Which is the most important experiment? ›

1. Galileo Galilei's Experiment on Speed of Falling Objects. Before Galileo, Aristotle had argued that heavy objects fall at a faster rate than lighter objects. But Galileo who is famed for his work on gravity, motion and light proved that objects fall at the same speed irrespective of their weight.

What are the top 10 science fair projects? ›

Here are some popular science fair projects that give a lot of bang for the buck.
  • Baking Soda and Vinegar Volcano. ...
  • Mentos and Soda Fountain. ...
  • Invisible Ink. ...
  • Crystal Growing. ...
  • Vegetable Battery. ...
  • Wind Energy. ...
  • Water Electrolysis. ...
  • Plant Science.
13 Sept 2019

How does psychology improve quality of life? ›

Psychologists use scientific research to better understand how people learn, interpret events and make decisions. They then translate that knowledge into techniques to help people make smarter choices in their daily lives.

How can psychology change your life? ›

Insight into people's behaviour

By studying psychology, you gain a deeper access to the human mind that gives new meaning to how people express emotions, handle stress, give and receive love, and, indeed, why certain situations affect some people more than others.

What is the biggest rule of psychology to our everyday life? ›

Motivation is the most important psychological aspect that plays a crucial role in achieving our goals. While doing any task in your daily life, if you are not motivated enough, then you won't be able to give your best.

What is an example of a classical experiment? ›

Some of the most famous examples include Milgram's obedience experiment and Zimbardo's prison experiment. Explore some of these classic psychology experiments to learn more about some of the best-known research in psychology history.

What are the three classical experiment? ›

Among these experiments are the Electrical Discharge Experiment, Thermal Synthesis, and The Protocell Experiment.

Why is classical experimental design important? ›

The classical experiment design serves as the foundation for all modern experiments. Major components of this method include independent and dependent variables, pre-testing and post-testing, and experimental and control groups.

What was the first experiment in psychology? ›

Wundt is credited with conducting the first formal experiment in psychology, where he tried to assess the speed of thought by measuring how long it took test subjects to make a judgment.

Why is experimental psychology important to us? ›

Experimental psychologists are interested in exploring theoretical questions, often by creating a hypothesis and then setting out to prove or disprove it through experimentation.

What is the main purpose of an experiment? ›

An experiment is a procedure carried out to support or refute a hypothesis, or determine the efficacy or likelihood of something previously untried. Experiments provide insight into cause-and-effect by demonstrating what outcome occurs when a particular factor is manipulated.

What are the steps of a classical experiment? ›

Several kinds of experimental designs exist. In general, designs considered to be classic experiments contain three key features: independent and dependent variables, pretesting and posttesting, and experimental and control groups.

Why experimental research is important? ›

If you don't have enough data to support your decisions, you must first determine the facts. Experimental research gathers the data necessary to help you make better decisions. Any research conducted under scientifically acceptable conditions uses experimental methods.

What is an example of experimental research? ›

The most basic example of experimental research is laboratory experiments, which may differ in nature depending on the subject of research.

How do you make a psychological experiment? ›

Draw your conclusion and share the results with the scientific community.
  1. Find a Research Problem or Question. ...
  2. Define Your Variables. ...
  3. Develop a Hypothesis. ...
  4. Conduct Background Research. ...
  5. Select an Experimental Design. ...
  6. Standardize Your Procedures. ...
  7. Choose Your Participants. ...
  8. Conduct Tests and Collect Data.
10 Apr 2020

What are some good experimental research topics? ›

The best experimental research topics for school or college student.
Following are the fields from which experimental research topics for stem students can be framed:
  • Magnifying lens Discovery.
  • Centripetal Force & Centrifugal Force.
  • Electromagnetics.
  • Nuclear Fusion & Fission.
  • Optical Fiber.
  • Electricity.

What is social psychology experiments? ›

A social experiment is a type of psychological or sociological research for testing people's reactions to certain situations or events. The experiment depends solely on a particular social approach where the main source of information is people with their knowledge and point of view.

What makes experimental psychology unique? ›

Using scientific methods to collect data and perform research, experimental psychology focuses on certain questions, and, one study at a time, reveals information that contributes to larger findings or a conclusion.

What are the characteristics of experimental psychology? ›

Experimental psychologists employ human participants and animal subjects to study a great many topics, including (among others) sensation & perception, memory, cognition, learning, motivation, emotion; developmental processes, social psychology, and the neural substrates of all of these.

What are the advantages and disadvantages of experimental method in psychology? ›

List of Advantages of Experimental Research
  • It gives researchers a high level of control. ...
  • It allows researchers to utilize many variations. ...
  • It can lead to excellent results. ...
  • It can be used in different fields. ...
  • It can lead to artificial situations. ...
  • It can take a lot of time and money. ...
  • It can be affected by errors.

What are the 9 types of experimental research? ›

The main experimental designs are:
  • The completely randomised design. ...
  • The randomised block design. ...
  • Latin square designs. ...
  • Factorial designs. ...
  • Split plot designs. ...
  • Repeated measures designs in which each experimental unit is measured several times without different treatments being applied and time effects are of interest.

What are the 5 components of experimental design? ›

The components of experimental design are control, independent variable and dependent variable, constant variables, random assignment and manipulation.

What are the different types of experimental designs in psychology? ›

Types of design include Repeated Measures, Independent Groups, and Matched Pairs designs.
  • Repeated Measures Design. Where the same participants are allocated to all groups (i.e. take part in all conditions) of an experiment. ...
  • Independent Groups Design. ...
  • Matched Pairs Design.
22 Mar 2021

How many years do you have to study to be a psychologist? ›

A first B-degree with psychology as a major subject (3 – 4 years) 2. A postgraduate honours degree in psychology (1-2 years) 3. A professional masters degree in clinical psychology or research psychology (2 years).

How many years does it take to study psychology? ›

The Bachelor of Science in Psychology (BS Psych) is a four-year program designed to help you observe human behavior through the scientific method, allowing you to gain access to the human psyche and fathom its depths.

Is becoming a psychologist worth it? ›

If you enjoy working with people and helping them achieve their full potential, then becoming a psychologist can be extremely rewarding. While you will often face challenges, seeing your clients make real progress and work towards their goals can give you a feeling of accomplishment.

Which country is best for studying psychology? ›

Best Countries to Study Psychology
  • USA.
  • Austria.
  • UK.
  • France.
  • Denmark.
  • The Netherlands.
  • Australia.
  • Canada.

Can you do psychology without Science? ›

A. In case a student wishes to pursue BSc in Psychology, then it is necessary for him/her to study Science stream in Class 11 and 12. For a BA in Psychology, it is not mandatory to study Science.

Is psychologist a doctor? ›

Psychiatrists are medical doctors, psychologists are not. Psychiatrists prescribe medication, psychologists can't. Psychiatrists diagnose illness, manage treatment and provide a range of therapies for complex and serious mental illness. Psychologists focus on providing psychotherapy (talk therapy) to help patients.

What is the hardest psychology to study? ›

1. Parapsychology. By its very nature, parapsychology is even more vague than “traditional” mental health practices. It's the study of nonquantifiable phenomena, such as telepathy, telekinesis, extrasensory perception, and mind reading.

What is the easiest degree to get? ›

The 16 Easiest College Majors – 2022 Rankings
  • Psychology.
  • Criminal Justice.
  • English.
  • Education.
  • Religious Studies.
  • Social Work.
  • Sociology.
  • Communications.
11 Sept 2022

Is law better than psychology? ›

See both are different field. Law is based on your speaking power, confidence level in you, remembering all rules and acts,etc. Psychology is based on your thinking capacity and how u handle situations/problems faced by others.

What was one of the best known social experiments? ›

Learn more about some of the most famous experiments in the history of social psychology.
  • The Asch Conformity Experiments. Jay Lopez. ...
  • The Bobo Doll Experiment. Jay Lopez. ...
  • The Stanford Prison Experiment. Darrin Klimek / Getty Images. ...
  • The Milgram Experiments. Jay Lopez.
14 Dec 2020

What are some famous case studies? ›

Some famous examples of case studies are John Martin Marlow's case study on Phineas Gage (the man who had a railway spike through his head) and Sigmund Freud's case studies, Little Hans and The Rat Man. Case studies are widely used in psychology to provide insight into unusual conditions.

What is the halo effect experiment 1977? ›

The Halo Effect Experiment, 1977

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.

How can I learn psychology? ›

Today, there are plenty of great ways to learn more about the human mind and behavior such as taking a college course, signing up for a free online class, or self-studying using online resources.

Is psychology hard to study? ›

Psychology is one of the more difficult degrees and many of your assignments will require you to cite your sources and will require you to back up a lot of the arguments that you have.

How can I study psychology? ›

By following these relatively simple strategies, you can be sure that you'll be ready when test day arrives.
  1. Start Studying Early. ...
  2. Become an Active Listener. ...
  3. Review Your Class Notes Frequently. ...
  4. Form a Psychology Study Group. ...
  5. Take Practice Quizzes. ...
  6. Think of Real World Examples. ...
  7. Review Material in Multiple Ways.
29 Nov 2020

Why are experiments important in social psychology? ›

1 Experiments. The experimental method is often preferred in research on behavior because a properly designed experiment can allow cause and effect conclusions to be made. Many studies in social psychology are experiments. These types of studies can be done in a laboratory setting or in a natural setting.

What was the first experiment of social psychology? ›

For generations, social psychology students have read that Norman Triplett did the first social psychology experiment in 1889, when he found that children reeled in a fishing line faster when they were in the presence of another child than when they were alone.

What is experiment in psychology? ›

An experiment involves the manipulation of an independent variable, the measurement of a dependent variable, and the exposure of various participants to one or more of the conditions being studied. Random selection of participants and their random assignment to conditions also are necessary in experiments.

Which is the best example of a case study psychology? ›

One of the most famous case studies in psychology is that of Chris Sizemore. She was one of the first people to be diagnosed with multiple personality disorder, now called dissociative identity disorder. In her case, the “alter” personalities were all merged into one personality over which she had control.

What is another example of a good case study that a psychologist may want to study? ›

Examples of case studies in examples are those of Phineas Gage, Chris Sizemore, and Jill Price. Phineas Gage suffered from a brain injury during a railroad accident that changed his personality. Psychologists often cite his case as a way to understand traumatic brain injuries and their possible effects on personality.

Which is the best case study? ›

The top 40 cases were supervised by 22 different Yale SOM faculty members, several supervising two cases or more.
Top 40 Most Popular Case Studies of 2020.
1Marina Bay Sands
2Coffee 2016
3Search Fund Company Boards: How CEOs Can Build Boards to Help Them Thrive
4Ant Financial: Flourishing Farmer Loans at MYbank
36 more rows
25 Mar 2021

Is halo effect good or bad? ›

The halo effect works both in both positive and negative directions: If you like one aspect of something, you'll have a positive predisposition toward everything about it. If you dislike one aspect of something, you'll have a negative predisposition toward everything about it.

What is the opposite of the halo effect? ›

The horn effect is essentially the complete opposite of the halo effect. The horn effect is a cognitive process in which we immediately ascribe negative attitudes or behaviours to someone based on one aspect of their appearance or character.

How do you overcome the halo effect? ›

To minimize the influence of the bias, one can look to various cognitive debiasing techniques such as slowing down one's reasoning process. For example, if you are aware of the halo effect, you can mitigate the effect of the bias by trying to create two possible impressions of people when you first meet them.


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