In 2009, following the abuse of prisoners at its Guantanamo Bay detention camp, the US government made a significant decision. It moved the responsibility for 'enhanced interrogation techniques' from the CIA to a new government organization: the High-Value Detainee Interrogation Group (HIG). The move upset many CIA insiders; torture had been in their toolkit since the early days of the cold war. The remarks of one official at a HIG-organized conference on torture in Washington DC can be summed up as: how could a new agency, created to both conduct and study torture, replace the decades of practice and perfection attained by the CIA? By adding a scientific component, responded the newly appointed head of the HIG.

This exchange highlights the theme of neuroscientist Shane O'Mara's Why Torture Doesn't Work. Rightly, O'Mara takes a moral stand against torture (forced retrieval of information from the memories of the unwilling). However, instead of simply providing utilitarian arguments, he argues that there is no evidence from psychology or neuroscience for many of the specious justifications of torture as an information-gathering tool. Providing an abundance of gruesome detail, O'Mara marshals vast, useful information about the effects of such practices on the brain and the body.

For instance, he explains why, physiologically, it is ludicrous to claim that stress, pain and fear will coerce a suspect to surrender critical information. The prolonged release of stress hormones such as cortisol damages the hippocampus — a brain structure crucial for encoding and retrieving memories — as well as the prefrontal cortex, which is implicated in decision-making and executive control processes. Such damage works in opposition to the goal of torture. Furthermore, chronic stress creates a negative feedback loop, causing enlargement and hyperresponsiveness of the amygdala, the brain structure that underlies emotional salience, directs attention, enables learning and communicates with most of the brain.