An experiment in a basement
In August 1961, psychologist Stanley Milgram began a series of experiments in the basement of Linsly-Chittenden Hall at Yale University. The study was advertised to local men as a scientific investigation of memory and learning, paying participants $4.50 for one hour of their time. Each participant, upon arrival, was introduced to a stern man in a grey lab coat, the "Experimenter," and another supposed participant, who was actually a confederate in the study.
A rigged draw always assigned the true subject to the role of "Teacher" and the confederate to the role of "Learner." The Teacher watched as the Learner was strapped into a chair with electrodes attached to his arms. The Teacher was then taken to an adjacent room and seated in front of an imposing shock generator. The machine had a row of 30 switches, starting at 15 volts and increasing in 15-volt increments to a maximum of 450 volts. Labels on the machine described the shock levels, ranging from "Slight Shock" to "Danger: Severe Shock" and, finally, "XXX" for the highest two levels. To convince the Teacher of the machine's authenticity, a real 45-volt sample shock was administered to them before the test began. The task was simple: the Teacher would read word pairs, and for every incorrect answer from the Learner, they were to administer an electric shock, increasing the voltage with each error.
Prods and protests
As the experiment progressed, the Learner—following a script—would provide intentionally wrong answers. The Teacher would then be required to administer the next level of shock. The shocks were fake, and the Learner's reactions were pre-recorded sounds played from a tape recorder. At 75 volts, the Learner would grunt. At 150 volts, he would demand to be released from the experiment. At 300 volts, he would refuse to answer any more questions. After 330 volts, the Learner fell completely silent.
Many participants showed extreme stress, sweating and trembling to stop the experiment. When a Teacher expressed hesitation, the Experimenter would use a sequence of four standardized verbal prods: "Please continue," "The experiment requires that you continue," "It is absolutely essential that you continue," and "You have no other choice, you must go on." If a participant still refused after the fourth prod, the experiment was halted. In the first and most famous variation of the experiment, 65% of participants continued to administer shocks up to the final 450-volt level. Every single participant proceeded to at least the 300-volt mark.