A quick glance at someone's facial structure may be enough to predict how temperamental a person is, say researchers.
Facial width-to-height ratio (WHR) may help predict people's tendency towards aggression. WHR is determined by measuring the distance between the right and left cheeks and the distance from the upper lip to the mid-brow.
During childhood, boys and girls have similar facial structures, but during puberty, males develop a greater WHR than females.
Previous research has suggested that males with a larger WHR act more aggressively than those with a smaller WHR.
In the new study, the research team from Brock University sought to determine if it is possible to predict another person's propensity for aggressive behaviour simply by looking at their photograph.
The volunteers viewed photographs of faces of men for whom aggressive behaviour was previously assessed in the lab. The volunteers rated how aggressive they thought each person was on a scale of one to seven after viewing each face for either 2000 milliseconds or 39 milliseconds.
The photographs were very revealing: Volunteers' estimates of aggression correlated highly with the actual aggressive behaviour of the faces viewed, even if they saw the picture for only 39 milliseconds.
Moreover, the volunteers' estimates were also highly correlated with WHR of the faces-the greater the WHR, the higher the aggressive rating, suggesting that we may use this aspect of facial structure to judge potential aggression in others.
These findings indicate that subtle differences in face shape may affect personality judgments, which may, in turn, guide how we respond to certain individuals.
The study appears in Psychological Science, a journal of the Association for Psychological Science.