Especially if the person being shocked in the next room started moaning (at 75 volts) and then yelling, "Hey, that really hurts" (at 120 volts) and then at 150 volts, "Experimenter, get me out of here! I refuse to go on!" At 180 volts the victim cries, "I can't stand the pain." Later, there are agonized screams after every shock, and he pounds on the wall pleading with you, and finally, at 330 volts, the subject falls silent. When the shocker wants to stop, the psychologist simply says, "Please continue" or "You must go on." What would most people do? .
Amazingly, 60% of the subjects went all the way to 450 volts! In fact, every one of the 40 subjects administered at least 300 volts! Milgram wrote, "Many subjects will obey the experimenter no matter how vehement the pleading of the person being shocked. It is the extreme willingness of adults to go to almost any lengths on the command of an authority that constitutes the chief finding of this study and the fact most urgently demanding explanation"(internet source). The subjects administering the shock were not sadistic monsters, nor very angry, nor prejudiced, nor indifferent against the learner. Instead, they appeared to be very stressed. This deference to authority is a serious problem, not just in terms of bowing down to government officials, but also to experts, doctors, bosses, owners, authors, and many others who are eager to tell you what to do.
So, why or how do we humans do such things? Milgram indicates that the subjects (1) became absorbed in pleasing the authority and doing their assignment just right, (2) denied their responsibility, "the experimenter was a Ph. D." or just like Adolf Eichmann, many of the subjects said, "I wouldn't have done it by myself, I was just doing what I was told," (3) started to believe that the experiment was vitally important and that the pursuit of truth is a "noble cause" (even though someone has to suffer), (4) blamed the victim, "he was so stupid and stubborn he deserved to get shocked," and, most importantly, (5) just couldn't bring themselves to act on their values and defy authority (Milgram 317-327).