Stanley Milgram conducted an experiment on "Obedience to Authority" in which volunteers were given the role of a teacher. As the teacher they were instructed to ask a series of questions to a "learner". Every time the "learner" got an answer wrong, they pressed the next in a series of buttons. Each button, they were told, administered a higher and higher voltage of electric shock to the learner. They were told that the shocks would hurt, and could even kill the learner. The learner was, infact, an actor, pretending that they were receiving the shocks.

Milgram's experiment was to see how far the volunteer would go.

Over 90% of the volunteers in the teacher role continued up the scale of buttons, until 450 volts, no matter how much the learner screamed, and begged for the experiment to be stopped.

Milgram concluded that obedience to authority is a "danger to survival inherent in our make-up", and that our conscious mind would prefer we inflict harm upon others, than be disobedient to an authority figure.

Paraphrased from an article on Obedience found at: