[The following is an exact transcript of this podcast.]

You’ve heard of 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 Sciences, 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.

—Karen Hopkin