Theories proposed to explain obedience were focussed on individual differences (e.g., authoritarian personality, frustration-aggression); whereas other theories were focused on the situation of the person.
These inhumane policies may have originated in the mind of a single person, but they could only be carried out on a massive scale if a very large number of persons obeyed orders.
In Milgram’s infamous study, participants were subjected to a 'learning' experiment at Yale university, using a shock generator with switches ranging from 15-450 volts.
In Milgram’s study, participants were subjected to a series of prods delivered in order when they refused to continue, such as "Please continue" or "Please go on".
Criticisms of Milgram’s study include the deception involved, using only male participants, improvised instructions, and not fully debriefing all participants.
Variations of Milgram’s experiment include an experiment in an office building where obedience was mostly maintained, an experiment with an ordinary person giving the orders, and two experimenters, contradictory commands.
To test obedience beyond Milgram, an experiment was conducted with nurses as participants, where 21 of 22 nurses administered a lethal dosage of medication to a patient.
Stanley Milgram’s explanation for obedience is that humans obey because of the survival value of hierarchies, coping better with threats as a group, giving stability and harmony to relations within groups, and obedience is usually rewarded from experiences in their family and institutional settings.
In Zimbardo's study, participants went beyond the surface demands of role-playing, with most sadistic behaviours occurring when guards thought they weren't being observed and were in an 'off' phase of the experiment.
Zimbardo pointed to various situational/psychological processes to explain how negative situational forces can overwhelm positive dispositional tendencies.
When in 'off' phases, only 10% of prisoner conversations were autobiographical, indicating a lack of opportunity to transcend the experimental environment and present their personal identity.
Zimbardo's conclusions include that situations can have a profound effect on individual behaviour and mental functioning to a point where people behave in ways they would not have thought possible.