Ultimately, they tend to go along with the Experimenter if he justifies their actions in terms of the scientific benefits of the study (as he does with the prod “The experiment requires that you continue”) [39]. But if he gives them a direct order (“You have no other choice, you must go on”) participants typically refuse.
This seems very suspicious because I remember offhand that the former is an early prompt and the second one is the final prompt given only after the other prompts have been exhausted.
Here is a paper in PLOS Biology re-considering the lessons of some classic psychology experiments invoked here often (via).
Contesting the “Nature” Of Conformity: What Milgram and Zimbardo's Studies Really Show
To me the crux of the paper comes from this statement in the abstract:
Plus this detail from the Milgram experiment: