Milgram's personal archive reveals how he created the 'strongest obedience situation'

Stanley Milgram's 1960s obedience to authority experiments, in which a majority of participants applied an apparently fatal electric shock to an innocent 'learner', are probably the most famous in psychology, and their findings still appall and intrigue to this day. Now, in a hunt for fresh clues as to why ordinary people were so ready to harm another, Nestar Russell, at Victoria University of Wellington, has reviewed Milgram's personal notes and project applications, which are housed at Yale University's Sterling Memorial Library.

Milgram trained under Solomon Asch, author of the famous conformity experiments, and the obedience project was originally conceived as an extension of Asch's work. Milgram was going to see how the behaviour of a group of cooperating participants (actually confederates working for the researcher) influenced the naive participants' willingness to harm another. A condition in which single participants followed the experimenter's orders on their own was planned as a mere control condition.

It was during Milgram's extensive pilot work that he discovered the remarkable willingness for participants to obey instructions, without the need for group coercion, thus changing the direction of his project. The focus shifted to lone participants and Milgram began a process of trial and error pilot work to identify the perfect conditions for inducing obedience - what he described as 'the strongest obedience situation'.

Early on, Milgram recognised the need for an acceptable rationale for harming another and so he invented the cover story that the experiment was about using punishment to improve learning. To counter participants' reluctance to harm an innocent person, Milgram also devised several other 'strain resolving mechanisms'. This included replacing the final shock level label 'LETHAL' with the more ambiguous 'XXX'; removing a Nazi-sounding 'pledge to obey' from the experiment instructions; and creating physical distance between the participants and the innocent, to-be-electrocuted learner.

In fact, this latter factor worked too well. When Milgram removed any sight or sound of the learner, 'virtually all' participants showed a willingness to inflict lethal harm. Milgram realised this near-total obedience was counter-productive and would prevent his paradigm from 'scaling obedient tendencies'. For his first official experiment he therefore settled on auditory feedback only, in the form of the learner banging on the wall in distress.

Another 'strain resolving mechanism' that Milgram devised included increasing the number of levels on the shock generator. This allowed for exploitation of the 'foot in the door' persuasion effect whereby people are more likely to cooperate once they have already agreed to a less significant request - a kind of piecemeal compliance.

Milgram was also careful about the actors he chose to play the part of experimenter and learner. Though both non-professionals, the man acting as learner was chosen because he was 'mild and submissive; not at all academic' and a 'perfect victim', whilst the man playing the experimenter was 'stern' and 'intellectual looking'. Finally, Milgram was careful to plan things so that the 'experimenter', whenever challenged, replied that he was responsible for anything that happens to the learner.

Taken altogether, Russell's new analysis shows how Milgram used ad hoc trial and error pilot testing to hone his methodology and ensure his first official obedience experiment achieved such a high obedience rate (of 65 per cent). 'Knowing step-by-step how Milgram developed this result may better arm theorists interested in untangling this still enigmatic question of why so many participants inflicted every shock,' Russell said.
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Russell, N. (2010). Milgram's obedience to authority experiments: Origins and early evolution. British Journal of Social Psychology DOI: 10.1348/014466610X492205 [Open Access]