What did the milgram experiment show?

Milgram's experiment showed a number of things. The initial experiment involved participants being asked to give apparently harmful and potentially lethal electric shocks to a stooge (who they thought was simply a participant) upon the stooge's incorrect answers. It was estimated by Psychiatrists that most people would drop out early on and refuse to keep on giving shocks, and that nobody would go all the way to 400 volts. In actuality, everyone sent severe and dangerous shocks of 300 volts, and most went all the way.

This shows that people are generally willing to obey an authority figure, even when it might lead to harming or even killing another person.

Milgram also did a number of variations on his experiment, with it taking place in an old office block, with the experimenter phoning through instructions, with other stooges acting as support, or refusing to continue the experiment, and so on.

These variations showed that people are less likely to obey if their victim is closer, if the setting doesn't suggest legitimate authority, if the experimenter is not nearby, or if other participants are refusing to obey. They also showed that someone is much more likely to obey if the participant believes someone else is sending the shocks, not them.