We like to idolise fearlessness and we equate it to bravery but there is a fine line between that and stupidity. Immunity to the pangs of fear would leave someone unable to assess threats to themselves and to other people, which means that fear not only has consequences for an individual but for their entire social circle. Guillaume Martel and colleagues from Rutgers University demonstrated these far-reaching consequences by examining a special group of mice which had been genetically engineered to be fearless.

Martel’s team focused their attention on the amygdalae, a pair of almond-shaped structures, one in each half of the brain, that play an important role in emotion, and particularly in creating and storing memories linked to emotional events.