So far, the debate has largely used anecdotes as evidence, but a new paper looks to neurobiology to end the debate. Writing in the journal Trends in Cognitive Sciences, Shane O'Mara, a behavioral neurophysiologist at Trinity College in Dublin, Ireland, claims that torture like waterboarding is specifically designed to interfere with the same part of the brain responsible for memory and decision making.
According to O'Mara, repeated high levels of stress can shrink the hippocampus and prefrontal cortex regions of the brain. Those regions control memory recall and higher level decision making. By attacking those regions of the brain, torture makes the victim more supple and less cagey, but also prevents the detainee from recalling accurate memories and picking the right information to tell interrogators.
Additionally, as those region undergo changes in reaction to torture, the brain becomes more likely to fix false memories. Thus, repeated waterboarding and questioning, like that applied to 9/11 mastermind Khalid Sheik Mohammad, increases the likelihood of false information.