What Was the Milgram Experiment?

Milgram's Famous and Controversial Studies of Obedience

The original shock box used in Milgram's obedience experiments
Milgram's original "shock box" displayed at the Ontario Science Centre.

Isabelle Adam (CC BY-NC-ND 2.0) via Flickr

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The Milgram experiment was a famous and controversial study that explored the effects of authority on obedience.

During the 1960s, Yale University psychologist Stanley Milgram conducted a series of obedience experiments that led to some surprising results.

In the study, an authority figure ordered participants to deliver what they believed were dangerous electrical shocks to another person. These results suggested that people are highly influenced by authority, and highly obedient.

More recent investigations cast doubt on some of the implications of Milgram's findings and even the results and procedures themselves. Despite its problems, the study has, without question, made a significant impact on psychology.

Milgram started his experiments in 1961, shortly after the trial of the World War II criminal Adolf Eichmann had begun. Eichmann’s defense that he was merely following instructions when he ordered the deaths of millions of Jews roused Milgram’s interest.

In his 1974 book "Obedience to Authority," Milgram posed the question, "Could it be that Eichmann and his million accomplices in the Holocaust were just following orders? Could we call them all accomplices?"

Procedure in the Milgram Experiment

The participants in the most famous variation of the Milgram experiment were 40 men recruited using newspaper ads. In exchange for their participation, each person was paid $4.50.

Milgram developed an intimidating shock generator, with shock levels starting at 15 volts and increasing in 15-volt increments all the way up to 450 volts. The many switches were labeled with terms including "slight shock," "moderate shock," and "danger: severe shock." The final three switches were labeled simply with an ominous "XXX."

Each participant took the role of a "teacher" who would then deliver a shock to the "student" in a neighboring room whenever an incorrect answer was given. While participants believed that they were delivering real shocks to the student, the “student” was a confederate in the experiment who was only pretending to be shocked.

As the experiment progressed, the participant would hear the learner plead to be released or even complain about a heart condition. Once they reached the 300-volt level, the learner would bang on the wall and demand to be released.

Beyond this point, the learner became completely silent and refused to answer any more questions. The experimenter then instructed the participant to treat this silence as an incorrect response and deliver a further shock.

Most participants asked the experimenter whether they should continue. The experimenter then responded with a series of commands to prod the participant along:

  1. "Please continue."
  2. "The experiment requires that you continue."
  3. "It is absolutely essential that you continue."
  4. "You have no other choice; you must go on."

Results of the Milgram Experiment

In the Milgram experiment, obedience was measured by the level of shock that the participant was willing to deliver. While many of the subjects became extremely agitated, distraught, and angry at the experimenter, they nevertheless continued to follow orders all the way to the end.

Milgram's results showed that 65% of the participants in the study delivered the maximum shocks. Of the 40 participants in the study, 26 delivered the maximum shocks, while 14 stopped before reaching the highest levels.

Factors That Influence Obedience

Why did so many of the participants in this experiment perform a seemingly brutal act when instructed by an authority figure? According to Milgram, there are some situational factors that can explain such high levels of obedience:

  • The physical presence of an authority figure dramatically increased compliance.
  • The fact that Yale (a trusted and authoritative academic institution) sponsored the study led many participants to believe that the experiment must be safe.
  • The selection of teacher and learner status seemed random.
  • Participants assumed that the experimenter was a competent expert.
  • The shocks were said to be painful, not dangerous.

Later experiments conducted by Milgram indicated that the presence of rebellious peers dramatically reduced obedience levels. When other people refused to go along with the experimenter's orders, 36 out of 40 participants refused to deliver the maximum shocks.

More recent work by researchers suggests that while people do tend to obey authority figures, the process is not necessarily as cut-and-dried as Milgram depicted it.

In a 2012 essay published in PLoS Biology, researchers suggested that the degree to which people are willing to obey the questionable orders of an authority figure depends largely on two key factors:

  • How much the individual agrees with the orders
  • How much they identify with the person giving the orders

While it is clear that people are often far more susceptible to influence, persuasion, and obedience than they would often like to be, they are far from mindless machines just taking orders. 

Ethical Concerns in the Milgram Experiment

Milgram's experiments have long been the source of considerable criticism and controversy. From the get-go, the ethics of his experiments were highly dubious. Participants were subjected to significant psychological and emotional distress.

Some of the major ethical issues in the experiment were related to:

  • The use of deception
  • The lack of protection for the participants who were involved
  • Pressure from the experimenter to continue even after asking to stop, interfering with participants' right to withdraw

Due to concerns about the amount of anxiety experienced by many of the participants, everyone was supposedly debriefed at the end of the experiment. The researchers reported that they explained the procedures and the use of deception.

Critics of the study have argued that many of the participants were still confused about the exact nature of the experiment, and recent findings suggest that many participants were not debriefed at all.

Replications of the Milgram Experiment

While Milgram’s research raised serious ethical questions about the use of human subjects in psychology experiments, his results have also been consistently replicated in further experiments. One review further research on obedience and found that Milgram’s findings hold true in other experiments.

In 2009, researchers conducted a study designed to replicate Milgram's classic obedience experiment. The researchers made several alterations to Milgram's experiment.

  • The maximum shock level was 150 volts as opposed to the original 450 volts.
  • Participants were also carefully screened to eliminate those who might experience adverse reactions to the experiment.

The results of the new experiment revealed that participants obeyed at roughly the same rate that they did when Milgram conducted his original study more than 40 years ago.

Some psychologists suggested that in spite of the changes made in the replication, the study still had merit and could be used to further explore some of the situational factors that also influenced the results of Milgram's study. But other psychologists suggested that the replication was too dissimilar to Milgram's original study to draw any meaningful comparisons.

Recent Criticisms and New Findings

Psychologist Gina Perry suggests that much of what we think we know about Milgram's famous experiments is only part of the story. While researching an article on the topic, she stumbled across hundreds of audiotapes found in Yale archives that documented numerous variations of Milgram's shock experiments.

Participants Were Often Coerced

While Milgram's reports of his process report methodical and uniform procedures, the audiotapes reveal something different. During the experimental sessions, the experimenters often went off-script and coerced the subjects into continuing the shocks.

"The slavish obedience to authority we have come to associate with Milgram’s experiments comes to sound much more like bullying and coercion when you listen to these recordings," Perry suggested in an article for Discover Magazine.

Few Participants Were Really Debriefed

Milgram suggested that the subjects were "de-hoaxed" after the experiments. He claimed he later surveyed the participants and found that 84% were glad to have participated, while only 1% regretted their involvement.

However, Perry's findings revealed that of the 700 or so people who took part in different variations of his studies between 1961 and 1962, very few were truly debriefed.

A true debriefing would have involved explaining that the shocks weren't real and that the other person was not injured. Instead, Milgram's sessions were mainly focused on calming the subjects down before sending them on their way.

Many participants left the experiment in a state of considerable distress. While the truth was revealed to some months or even years later, many were simply never told a thing.

Variations Led to Differing Results

Another problem is that the version of the study presented by Milgram and the one that's most often retold does not tell the whole story. The statistic that 65% of people obeyed orders applied only to one variation of the experiment, in which 26 out of 40 subjects obeyed.

In other variations, far fewer people were willing to follow the experimenters' orders, and in some versions of the study, not a single participant obeyed.

Participants Guessed the Learner Was Faking

Perry even tracked down some of the people who took part in the experiments, as well as Milgram's research assistants. What she discovered is that many of his subjects had deduced what Milgram's intent was and knew that the "learner" was merely pretending.

Such findings cast Milgram's results in a new light. It suggests that not only did Milgram intentionally engage in some hefty misdirection to obtain the results he wanted but that many of his participants were simply playing along.


A review of Milgram's research materials suggests that the experiments exerted more pressure to obey than the original results suggested. Other variations of the experiment revealed much lower rates of obedience, and many of the participants actually altered their behavior when they guessed the true nature of the experiment.

Impact of the Milgram Experiment

Since there is no way to truly replicate the experiment due to its serious ethical and moral problems, determining whether Milgram's experiment really tells us anything about the power of obedience is impossible to determine.

So why does Milgram's experiment maintain such a powerful hold on our imaginations, even decades after the fact? Perry believes that despite all its ethical issues and the problem of never truly being able to replicate Milgram's procedures, the study has taken on the role of what she calls a "powerful parable."

Milgram's work might not hold the answers to what makes people obey or even the degree to which they truly obey. It has, however, inspired other researchers to explore what makes people follow orders and, perhaps more importantly, what leads them to question authority.


Recent findings undermine the scientific validity of the study. Milgram's work is also not truly replicable due to its ethical problems. However, the study has led to additional research on how situational factors can affect obedience to authority.

A Word From Verywell

Milgram’s experiment has become a classic in psychology, demonstrating the dangers of obedience. The research suggests that situational variables have a stronger sway than personality factors in determining whether people will obey an authority figure. However, other psychologists argue that both external and internal factors heavily influence obedience, such as personal beliefs and overall temperament.

11 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Russell N, Gregory R. The Milgram-Holocaust linkage: challenging the present consensus. State Crim J. 2015;4(2):128-153.

  3. Russell NJC. Milgram's obedience to authority experiments: origins and early evolution. Br J Soc Psychol. 2011;50:140-162. doi:10.1348/014466610X492205

  4. Haslam SA, Reicher SD. Contesting the "nature" of conformity: What Milgram and Zimbardo's studies really show. PLoS Biol. 2012;10(11):e1001426. doi:10.1371/journal.pbio.1001426

  5. Milgram S. Liberating effects of group pressure. J Person Soc Psychol. 1965;1(2):127-234. doi:10.1037/h0021650

  6. Perry G. Deception and illusion in Milgram's accounts of the obedience experiments. Theory Appl Ethics. 2013;2(2):79-92.

  7. Blass T. The Milgram paradigm after 35 years: some things we now know about obedience to authority. J Appl Soc Psychol. 1999;29(5):955-978. doi:10.1111/j.1559-1816.1999.tb00134.x

  8. Burger J. Replicating Milgram: Would people still obey today?. Am Psychol. 2009;64(1):1-11. doi:10.1037/a0010932

  9. Elms AC. Obedience lite. American Psychologist. 2009;64(1):32-36. doi:10.1037/a0014473

  10. Miller AG. Reflections on “replicating Milgram” (Burger, 2009). American Psychologist. 2009;64(1):20-27. doi:10.1037/a0014407

  11. Haslam SA, Reicher SD, Millard K, McDonald R. ‘Happy to have been of service’: The Yale archive as a window into the engaged followership of participants in Milgram’s ‘obedience’ experiments. Br J Soc Psychol. 2015;54:55-83. doi:10.1111/bjso.12074

By Kendra Cherry
Kendra Cherry, MS, is the author of the "Everything Psychology Book (2nd Edition)" and has written thousands of articles on diverse psychology topics. Kendra holds a Master of Science degree in education from Boise State University with a primary research interest in educational psychology and a Bachelor of Science in psychology from Idaho State University with additional coursework in substance use and case management.