Game offers clues about the psychopathic brain

The "Prisoner's Dilemma" game, in which participants decide whether to cooperate or betray other players, offers interesting insights into psychopathy, according to a new study.

James K. Rilling et al. asked 30 university students to play an extended version of the game while undergoing functional MRI scans. (Other players were outside the scanner.) Prior to the game, participants answered questions designed to measure their psychopathic tendencies.

Not surprisingly, participants who scored higher on psychopathy (particularly males) betrayed their fellow players more often. As a result, they received more "punishments" when other players betrayed them in turn.

"After such outcomes," the researchers say, "subjects scoring high in psychopathy showed less amygdala activation, suggesting weaker aversive conditioning to those outcomes." They also showed weaker orbitofrontal cortical activation when they chose to cooperate, and weaker activation within dorsolateral prefrontal and rostral anterior cingulate cortex when they chose to defect. These findings, the researchers say, "suggest that whereas subjects scoring low on psychopathy have emotional biases toward cooperation that can only be overcome with effortful cognitive control, subjects scoring high on psychopathy have an opposing bias toward defection that likewise can only be overcome with cognitive effort."