CHICAGO, Oct 3, 2007 (AFP) - Researchers have identified the part of the brain that processes the threat of punishment for flouting social rules, a finding that could have implications for understanding the behaviour of psychopaths, a study released Wednesday said.

In a series of experiments, investigators used brain scans to monitor the mental activity of volunteers as they thought about how to respond to a challenge involving a social norm -- in this case the principle of fairness.