In the journal Trends in Cognitive Science, psychologist Share O'Mara notes that torture can interfere with the brain's memory retrieval apparatus, making it counterproductive to the aim of producing useful information.
The scientist tried to prove it by the example of waterboarding.
Waterboarding is a form of torture that consists of immobilizing the victim on his or her back with the head inclined downwards, and then pouring water over the face and into the breathing passages, causing the captive to believe he or she is dying. By forced suffocation and inhalation of water, the subject experiences the sensation of drowning.
It is known that waterboarding used as a means to get suspected terrorists to talk. Some people object to such methods on the grounds that they amount to torture. But in the journal Trends in Cognitive Science, psychologist Shane O’Mara of Trinity College in Dublin raises another objection: torture's not likely to work.
Proponents claim that waterboarding's effective because prisoners will tell the truth to make the interrogation stop. But O’Mara says that’s not supported by scientific evidence. Harsh interrogation doesn’t motivate prisoners to tell the truth. It motivates them to talk. Because while they’re talking they’re not being waterboarded. But that doesn’t mean that what they say is true.
What’s more, prolonged extreme stress impairs memory retrieval. American Special Ops soldiers have been shown to have trouble recalling things they’d learned before being subjected to food- or sleep-deprivation as part of their training. That’s because stress hormones can compromise brain activity, especially in regions involved in memory.
O’Mara notes that mildly stressful events actually facilitate recall. So simply capturing, moving and then questioning prisoners, he says, should be stressful enough to get the information flowing, according to Scientific American.