Well, I found this article from Slate interesting. Hard to know exactly how true it is, but it rings truer to me than lots of the stuff I've read about waterboarding, etc:
EITs were used to break the will to resist, not to extract information directly. Hayden acknowledged that prisoners might say anything to stop their suffering. (Like the other panelists, he insisted EITs weren't torture.) That’s why “we never asked anybody anything we didn’t know the answer to, while they were undergoing the enhanced interrogation techniques. The techniques were not designed to elicit truth in the moment.”There's torture, and then there's torture of course. This was the clever stuff.
They figured they were smarter
than the ordinary martyr,
leaving no marks behind,
but shattering the mind.