What is the Milgram experiment?

The Milgram Experiment was a series of classical social psychology experiments conducted in the early 1960s by Yale University assistant professor Stanley Milgram. The American psychologist first described the experiments he conducted in his 1963 article Behavioral Study of Obedience and later, in his book Obedience to Authority: An Experimental View published in 1974, too.

Background and history

“The experiment requires that you continue. It is absolutely essential that you continue. You have no other choice - you must go on”. These were the words spoken to participants of the experiments. You are probably asking yourself: “Continue doing what?”. The answer might shock you - the goal of the experiment was to find out how far an individual would go when it comes to obeying an order given by an authority figure if it involved inflicting increasing pain on other people. 

Now, some of you are, most definitely, curious to know why Stanley Milgram was interested in conducting this particular type of research. The reason behind Milgram’s idea to do such a controversial experiment is that both his mother and father were Jewish. His parents and many of his other immediate and extended family members were deeply affected by the Holocaust genocide. The psychologist was born and lived with his parents and two siblings in New York, and some of his relatives who were Nazi concentration camp survivors stayed with the Milgram family for a while. All this had a profound impact on the researcher and led him to study people’s obedience levels toward authority.

In April 1961, former SS Colonel Adolf Eichmann went on trial for crimes against humanity in Israel. Throughout his trial, which ended with an absolutely fair death penalty, the man had tried to defend himself by saying that all he was doing was “following orders”.

That was what gave Milgram the idea of conducting similar research. The scientist’s main goal was to test how easily commands given by an authority figure could influence an average person into perpetrating staggering atrocities similar to monstrous acts committed by Nazis during World War II.

The essence of the Milgram experiment

In the original version of Stanley Milgram’s study, the forty participants (American men only) were told that the experiment aimed to study the relationship between punishment and human ability to learn and memorize. Then, each of them was introduced to a second person.

According to the explanations of the experimenter, this second person was a volunteer participating in the experiment as well. The subjects were also told that all of the people participating in the study would be randomly assigned to “teachers” and “learners” roles. In actuality, these "second persons” were nothing but actors hired by the experimenter’s team. The real participants would, obviously, always be the “teachers”.

During the research, the “learners” and the "teachers” were in separate rooms; however, the teachers could hear the learners through the wall. The learners had to memorize lists of words read out loud by the teacher. Then, the experimenter gave instructions to the teachers to ask the learners questions to check if they remembered those words. If some of the learners’ answers were incorrect, the teachers would be asked by a man wearing a white lab coat to give the learners electric shocks.

The shocks’ voltage level started at fifteen volts. In reality, the shocks were fake - they were simulated via an authentic-appearing shock generator, or shock box, as Milgram called it. But the thing is that the participants believed the shocks were real. Each time the learners gave a wrong answer, the teachers were given instructions to administer a higher shock (increased in 15-volt increments up to 450 volts) to the victims.

At 150-volt level, the learners would (pretend to) cry out in pain, begging the teachers to interrupt the study, in some cases, complaining about a heart condition. The “learners” would keep crying out with each shock until the voltage level reached 330 volts, after which, they would stop responding.

When the participants started hesitating about continuing with the experiment, they would be told to keep on doing what they were doing with increasing psychological pressure; at the end, the experimenter would use the above-mentioned phrase "You have no other choice, you must go on".

The original variation of the experiment

In the original research, the “teachers” and the “learners” were located in separate rooms in a laboratory of Yale University. The participants were told that they would only carry out the experimenter’s orders, and the latter bore full responsibility for everything that happened in the lab room.

The experimenters, as stated above, were wearing lab coats with University Professor badges on them. That was to examine the “power of uniform”. In actual fact, the study found that people will most likely obey an instruction if they firmly believe that the authority is fully legitimate.

Refined variations of the experiment

When the variation where the “teachers” and the “learners” were in the same room was conducted, the percentage of volunteers who proceeded to administer the 450-volt shock to the people who were supposed to memorize pairs of words dropped from 65% to 40%. Obedience levels decreased because the “teachers” were able to observe the “learners” in anguish in direct proximity to themselves. Speaking of which, the experiment also found that whenever the authority figure left the lab room and provided subsequent instructions over the phone, only 21% of the subjects gave the “learners” the full 450 volts.

Predictions before the experiment

Before carrying out the study, Milgram conducted a poll among fourteen Yale University psychology students about the possible outcomes of his future experiment. According to students’ predictions, a very insignificant percentage - from 0 to 3 out of 100 hypothetical volunteers would administer the highest electric shock to the “learners”.

The researcher also polled 40 psychiatrists who believed that by the moment the victims started begging the “teachers” to set them free, most participants would stop inflicting pain on the “learners”. By the 300-volt shock, when the victims refused to talk, according to that group of psychiatrists, only 3.73 percent of the subjects would keep torturing the actors they believed were ordinary people. And only 0.001% of the subjects, according to psychiatrists’ predictions, would give the highest shock to the person sitting in an adjoining room (or even the same room).

In addition, Stanley Milgram privately polled some of his colleagues. They also were fully certain very few subjects would go all the way up to the highest voltage shock.

Shocking results

According to the results of the second and most widely reported set of experiments conducted by Milgram, 65% (26 out of 40) of the participants gave the final and the strongest 450-volt electric shock to the “learners”, and 100% administered 300-volt shocks.

Horrifying, isn’t it?

If it makes you feel any better, most subjects were extremely uncomfortable inflicting pain on people while being acutely aware that the victims were suffering. In fact, they displayed different levels of distress and tension like sweating, stuttering, trembling, biting their lips; some volunteers were smiling or laughing nervously; some others even had seizures.

All participants paused the study at least once because they were in doubt whether it was okay to continue. Most went on with the experiment after being told that even though these shocks may be somewhat painful, no permanent tissue damage would occur, so it was not a big deal. However, a small percentage of the subjects refused to obey and even said they would refund the money ($4 per hour) they had been paid to participate in the study.

None of the “teachers” who refused to give the victims the highest shocks insisted that the experiment be stopped or left the lab room to check the health of the “learners” without asking the experimenter(s) for permission to leave.

Later, Stanley Milgram and other researchers carried out various versions of this experiment all over the world. The results were similar to those of the original study in every country.

Why were people so cruel to others?

Human behavior and mental processes are very complex. One of the most important things people have learned from the Milgram experiment was that some individuals are always ready to shirk personal responsibility. For instance, for many “teachers” who hesitated whether or not to keep pushing the button that was delivering electric shocks, it was enough that the experimenter plainly assured them that all the responsibility for what is happening was his, not theirs.

In some cases, the experimenter told the volunteers that what they are doing is for the good of science, asked them to continue, and most of them obeyed. The explanation of this behavior is pretty simple - some people identify with the cause of science, which is why they blindly obey someone who is a legitimate representative of science.

Different hypotheses have been put forward to explain the cruelty shown by the participants:

  • The Yale University authority hypnotized the subjects.
  • All volunteers were of masculine gender, so they had a biological propensity for aggressive behavior.
  • The subjects did not understand how much harm, not to mention pain, such powerful electrical shocks could cause to the “learners”.
  • The participants simply had a sadistic streak and enjoyed the opportunity to inflict suffering on people.

In further experiments, all these hypotheses have been rejected.

The results had nothing to do with the university name

Milgram repeated the experiment, renting a building in Bridgeport, Connecticut, under the banner of the Bridgeport Research Association, without using any reference to Yale University. The "Bridgeport Research Association" was a commercial organization. The results were close enough to the original ones: 48% of the subjects were okay with administering the highest electric shock to the victims.

The gender of the subjects did not influence the results

Another study showed that the gender of the subject did not change the results much either; The female "teachers" behaved exactly like the male teachers in Milgram's first and second experiments. That debunked the myth of feminine softheartedness.

People were well aware of the danger of electric shocks for the "learners"

Yet another experiment tested the assumption that the subjects underestimated the potential physical harm they caused to the victims. Before starting the additional research, the "learners" were instructed to declare that they had a weak heart and would not withstand strong electric shocks. During the experiment, the “learners” would start screaming: “Enough! Let me out of here! I told you that I have a bad heart. I’m starting to worry about my heart! I refuse to continue! Let me out!"

However, that did not make the "teachers" change their behavior at all: 65% of the subjects conscientiously performed their "duties", maximizing the voltage to the highest level.

The subjects were ordinary people

The suggestion that the participants had some mental disorders was also rejected as unfounded. The people who responded to Stanley Milgram's ad and expressed a desire to take part in an experiment to study the effect of punishment on memorization capacity were average citizens in terms of age, job, and educational level. Moreover, the way the subjects answered the questions of special tests that allow assessing personality showed that these people were quite normal and had a fairly stable psyche. As a matter of fact, they were no different from everyday people or, as Milgram said, "they are you and me".

The subjects were not sadists

The hypothesis that the subjects took pleasure in the suffering of the victim was refuted by several experiments:

  • When the experimenter left and his “assistant” remained in the room, only 20% of the participants agreed to continue the experiment.
  • When the volunteers were allowed to choose the voltage themselves, 95% stuck with 150 volts.
  • When the participants were given instructions over the phone, obedience levels dramatically reduced (up to 20%). At the same time, many participants pretended to continue the research.

While in front of two researchers, one of whom ordered to stop, and the other insisted on continuing the experiment, the subject interrupted the study (read more on this below).

Other variations of the experiment

In total, Milgram performed twenty-three variations of his research, each with a different script and actors.

In one of the versions of the experiment, where the volunteers and the actors were in the same room, the “teachers” had to force the “learners” hands onto the shock plate. The percentage of the people who went on to give the 450-volt electric shock to their victims dropped from 65% to 30%.

In yet another variation of the study, two experimenters (instead of one in the original version of the research) were present in the lab room with the fake electric shock machine. During the experiment, they would start arguing with each other about whether it was right or wrong to continue. The result of this version of the Milgram study was very different from the original ones - 0% of the “teachers” administered the strongest electric shock to the “learners”.

Other interesting facts found during the experiment

In some variations of the study, the “teachers” were allowed to choose the electric shock levels themselves. In these versions of the research, very few participants proceeded to the maximum voltage.

Another compelling piece of information gathered during the study was that when there was dissent between the experimenters and when they were absent from the lab room, obedience levels among the participants were much lower.

Criticism and controversy surrounding the experiment

Milgram has faced a lot of harsh criticism for his studies on ethical grounds. And it comes as no surprise because Milgram’s research subjects were indeed treated very unethically. The volunteers who participated in the experiment were brutally lied to - they were led to believe they were really harming other people.

Australian writer and psychologist Gina Perry conducted an investigation that revealed that some participants of Milgram's study were only told months later or, in some cases, were never told that the shocks were fake and the learners were not harmed in any way.

In her 2012 book Behind the Shock Machine: The Untold Story of the Notorious Milgram Psychology Experiments, Perry also questioned the validity of the study’s results. The writer has discovered that during the research, the experimenters have repeated their request to obey many more times than the script required.

Besides, several researchers have found that some of the “teachers” have probably realized that they were not actually inflicting pain on the “learners” in interviews conducted after the experiment, some participants told the scientists that they did not believe they were putting the “learners”’ lives at risk for real.


The primary conclusion of Milgram’s obedience research is that an everyday person will not think twice about harming other individuals when told to by an authority figure. The researcher also concluded that people were socialized to follow immoral orders, even the most horrible ones, by legitimate authority figures.

Milgram’s experiment definitely could not be recreated today because scientists are required to respect human dignity, safety, and well-being these days. In many people’s opinion, even if it were possible to conduct the same kind of experiment today, the results would have been different because humans have changed dramatically - and have changed for the better.