Milgram's study (1960's)

Milgram’s aim was to find out whether ordinary americans would obey an order that violated their personal morals from a figure of authority.

In order to do this 40 male volunteers were recruited through a newspaper advertisement. The participants were informed that the study was looking into the role of punishment in learning. Half played the role of the ‘teacher’, and half played the role of the ‘learner’. They were deceived into thinking that they were taking part in a learning and memory experiment. Every time that the 'learner' got a question wrong, the 'teacher' would give a shock.
  

The experiment continued until 450 volts were given 4 times, or the participants refused…