Would you electrocute someone if an authority figure told you to do so? Or give a response you know to be wrong if others in your group said it was right? For more people than you might think, the answer could be yes.
By Marya Burgess
Producer, BBC Radio 4's Mind Changers
Every day we try to fit in. We may like to think of ourselves as individuals but most of the time we don't actually want to stand out too much.
Psychologists sought to explain death camp workers' actions
It's this idea of conformity that the American social psychologist Solomon Asch studied in the 1950s, using nothing more complex than straight black lines drawn on pieces of card. It's one of the classic experiments in psychology, and Asch showed that many of us would rather deny the evidence of our own eyes than stand out from the group.
Asch believed in individual integrity and, at a time when social psychology was focussing on conformity to explain the Holocaust, he designed an experiment to prove that people would stand up against group pressure.
His unwitting subjects were unaware that the rest of the group were stooges or plants, who had been instructed to say that one line was the same length as another - even though it patently wasn't. Contrary to his expectations, Asch found that a third of people went along with the group, even when it contradicted the evidence of their own eyes.
But Asch found a way of explaining his results which tallied with his positive view of human nature: going along with your peers and acknowledging their views is a fundamentally social behaviour, without which society would collapse.
One of his students, Stanley Milgram, was profoundly influenced by Asch's work. If a third of people capitulated to peer pressure in this way, Milgram wondered what would happen if the pressure came from an authority figure.
In 1963 he conducted his infamous electric shock experiment, in which he led people to believe that they were giving someone electric shocks when they made mistakes on a word task.
Each was given the role of 'teacher' and, ensconced with the experimenter, was unable to see the 'learner', but well able to hear his screams as the shocks were delivered. The electric shock machine appeared to go right up to 450V with labels saying "Danger - severe shock".
The majority of 'teachers' showed some reluctance to turn the dial to increase the voltage, especially when the screams died down to be replaced by silence. But when they wanted to stop, the experimenter - the authority figure - insisted they carry on; 65% of people were willing to give potentially lethal shocks simply because the experimenter told them to.
Even though there were in fact no shocks, just a screaming actor, Milgram's experiment would be unlikely to get past an ethics committee today.
Still less so Philip Zimbardo's controversial Stanford Prison experiment in 1971, where assuming the uniform and the role of guards in a fake prison led students to inflict a regime of brutality on their fellow students who were playing the prisoners.
The BBC ran a reality TV version of the prison experiment last year
Whereas in Milgram's experiment the subjects passed responsibility to the authority figure, in Zimbardo's they assumed authority themselves.
Although a long way from the black lines on a piece of card to which they can trace their genesis, both experiments have been used to explain the shocking change in behaviour of apparently ordinary people when employed in Nazi death camps.
But perhaps the key, even there, was simply an unwillingness to stand out from the crowd, even if it meant denying what was seen.
The first episode of Mind Changers was broadcast on BBC Radio 4 on Tuesday, 9 December, 1100 GMT.