Wider headed men are more aggressive

Skull dimensions predicting behavior? It sounds like debunked 19th century criminal anthropology, but hold on. Here is some evidence from the Department of Psychology, Brock University:

Facial characteristics are an important basis for judgements about gender, emotion, personality, motivational states and behavioural dispositions. Based on a recent finding of a sexual dimorphism in facial metrics that is independent of body size, we conducted three studies to examine the extent to which individual differences in the facial width-to-height ratio were associated with trait dominance (using a questionnaire) and aggression during a behavioural task and in a naturalistic setting (varsity and professional ice hockey). In study 1, men had a larger facial width-to-height ratio, higher scores of trait dominance, and were more reactively aggressive compared with women. Individual differences in the facial width-to-height ratio predicted reactive aggression in men, but not in women (predicted 15% of variance). In studies 2 (male varsity hockey players) and 3 (male professional hockey players), individual differences in the facial width-to-height ratio were positively related to aggressive behaviour as measured by the number of penalty minutes per game obtained over a season (predicted 29 and 9% of the variance, respectively). Together, these findings suggest that the sexually dimorphic facial width-to-height ratio may be an ‘honest signal’ of propensity for aggressive behaviour.

This was only true of men, not of women. And yes, I realize “on average”. It looks like testosterone makes the skull wider, and so the higher a man’s testosterone levels, the wider his skull. And we all know testosterone is partially responsible for aggressive tendencies. A little more info: Facial structure is a reliable cue of aggressive behavior.

This is very interesting research. Hopefully the experts will do even more research, but I often wonder if there is anything useful that can be done with this kind of information without being discriminatory?