In 1961, a scientist conducted some experiments to see how long ordinary people would continue to harm another human being because they were told to do so by an authority figure. Here’s the outline of the story using quotes from Wikipedia in italics:
The Milgram experiment on obedience to authority figures was a series of social psychology experiments conducted by Yale University psychologist Stanley Milgram, which measured the willingness of study participants to obey an authority figure who instructed them to perform acts that conflicted with their personal conscience… The experiments began in July 1961, three months after the start of the trial of German Nazi war criminal Adolf Eichmann in Jerusalem.
Three persons are involved … an actor plays “the professor” and another actor plays “the learner.” The test subject is “the teacher” who watches the student connected to an apparatus designed to deliver an electric shock up to 440 volts, lethal shock. In order to make it seem real, the teacher is given a 45 volt shock to experience some of what the learner experiences. The purpose of the test is to see how long the teacher will continue to administer shocks before quitting.
In Milgram’s first set of experiments, 65 percent (26 of 40) of experiment participants administered the experiment’s final massive 450-volt shock, though many were very uncomfortable doing so; at some point, every participant paused and questioned the experiment; some said they would refund the money they were paid for participating in the experiment…
Milgram summarized the experiment in his 1974 article, “The Perils of Obedience”, writing: I set up a simple experiment at Yale University to test how much pain an ordinary citizen would inflict on another person simply because he was ordered to by an experimental scientist. Stark authority was pitted against the subjects’ strongest moral imperatives against hurting others, and, with the subjects’ ears ringing with the screams of the victims, authority won more often than not. The extreme willingness of adults to go to almost any lengths on the command of an authority constitutes the chief finding of the study …
Later, Milgram and other psychologists performed variations of the experiment throughout the world, with similar results. … the percentage of participants who are prepared to inflict fatal voltages remains remarkably constant, 61–66 percent, regardless of time or place…
A striking comment is made in the preceding video: “All evil begins with 15 volts … with a small first step.”
An extended series of videos is here:
Wikipedia article: http://en.wikipedia.org/wiki/Milgram_experiment
Searching at Youtube will generate multiple examples of the story of the experiment.