The famous experiment that I knew of took place at Yale, AFAIK, about a decade earlier than the Stanford experiments.
http://en.wikipedia.org/wiki/Milgram_experiment
Easily arguable as unethical, but sociologists look at the experiment as a rare gem to learn from, since the odds that anything like it will be replicated in the future are so slim (and perhaps for good reason).
From what I remember reading about it many years ago was that those who were "tortured" weren't tortured, but would scream as if they were in agony, or even just go dead silent as if they died. I think those who were giving out the "punishment" suffered the most traumatic stress, IIRC. Yet, they followed orders.