The memos also show interrogators asked for a ruling on whether the placing of a harmless insect in a cramped box with al-Qaeda terror suspect Abu Zubaydah equated to torture.
The technique "certainly does not cause physical pain" and therefore could not be termed as torture and should be permissible, one of the memos said.
Similarly, techniques included waterboarding or simulated drowning, walling and sleep deprivation also fell short of torture, the memos said.
Another memo details a "prototypical interrogation", which begins with a detainee stripped of his clothes, shackled, and hooded, "with the walling collar over his head and around his neck".
But despite releasing the four partially blacked-out memos detailing the tactics, Mr Obama said operatives who carried out the interrogations would not be prosecuted, saying they acted on orders and were defending their country.
"This is a time for reflection, not retribution,'' Mr Obama said.
"We have been through a dark and painful chapter in our history. But at a time of great challenges and disturbing disunity, nothing will be gained by spending our time and energy laying blame for the past.''
Human rights groups reacted with dismay to Mr Obama's decision to shield interrogators from prosecution.
"The Department of Justice appears to be offering a get-out-of-jail-free card to individuals who, by US Attorney General Eric Holder's own estimation, were involved in acts of torture," said Larry Cox, executive director of Amnesty International.
All i can say is "go obama!". lol. He's not perfect, but he's at least doing something.
Cherry
