Researchers have mapped an underlying “psychological signature” for people who are predisposed to holding extreme social, political and religious attitudes and supporting violence in the name of ideology. A new study suggests that a particular mix of personality traits and types of unconscious cognition – the ways our brain takes in basic information – is a strong predictor for extremist views across a range of beliefs, including nationalism and religious fervour. These mental characteristics include poorer working memory and slower “perceptual strategies” – the unconscious processing of changing stimuli, such as shape and colour – as well as tendencies towards...