Even normal, decent people can engage in acts of extreme cruelty when instructed to do so by others as was highlighted in classic social psychological studies conducted in the 1960s and 1970s.
Professors Alex Haslam and Stephen Reicher revisited these studies' conclusions and explained how awful acts involve not just obedience, but enthusiasm too-challenging the long-held belief that human beings are 'programmed' for conformity.
This belief can be traced back to two landmark empirical research programs conducted by Stanley Milgram and Philip Zimbardo in the 1960s and early 1970s.
Milgram's 'Obedience to Authority' research is widely believed to show that people blindly conform to the instructions of an authority figure, and Zimbardo's Stanford Prison Experiment (SPE) is commonly understood to show that people will take on abusive roles uncritically.
However, Professor Haslam, from the University of Queensland, argues that tyranny does not result from blind conformity to rules and roles. Rather, it is a creative act of followership, resulting from identifying with authorities who represent vicious acts as virtuous.
"Decent people participate in horrific acts not because they become passive, mindless functionaries who do not know what they are doing, but rather because they come to believe-typically under the influence of those in authority-that what they are doing is right," Professor Haslam explained.
Professor Reicher, of the University of St Andrews, added that it is not that they were blind to the evil they were perpetrating, but rather that they knew what they were doing, and believed it to be right.
These conclusions were partly informed by Professors Haslam and Reicher's own prison experiment, conducted in 2002 in collaboration with the BBC.
The study generated three findings. First, participants did not conform automatically to their assigned role; second, they only acted in terms of group membership to the extent that they identified with the group; and finally, group identity did not mean that people simply accepted their assigned position-it also empowered them to resist it.
Although Zimbardo and Milgram's findings remain highly influential, Professor Haslam argue that their conclusions do not hold up well under close empirical scrutiny.
Professor Reicher concluded that tyranny does not flourish because perpetrators are helpless and ignorant; it flourishes because they are convinced that they are doing something worthy.
They presented their review in the open access journal PLOS Biology.