Physiognomy - inferring personality traits from facial features - was outlawed by King George II in 1743, and has for many years been dismissed as a pseudoscience. However, modern research is showing not only that observers readily make inferences about other people's traits based on their facial appearance, but that these inferences are often highly accurate. For example, people can use facial appearance to judge a man or woman's sexual orientation and to predict the success of chief executives. Now Justin Carre and colleagues have added to this burgeoning literature by showing that observers are able to predict the aggressiveness of a man by the look of his face.
A first study involved 31 participants rating the aggressiveness of 37 men based on a two-second viewing of each of their faces in turn. All the men were Caucasian, clean-shaven, and had been photographed with a neutral facial expression. The men's actual aggressiveness had been measured in an earlier lab task. This was a simple game, with aggression revealed by the men's tendency to press a button that took points from an opponent, with no benefit for themselves. It's a well-validated measure that correlates with real-life aggressiveness.
The participants' estimates of the men's aggression correlated with the men's actual aggression as revealed in the lab task. Carre's team think the participants were using the width-to-height ratio of the men's faces as a cue to their aggression. The wider a man's face relative to its length, the more aggressive the participants tended to think he was. In turn, and consistent with prior research, the width-to-height ratio of the men's faces correlated with their levels of aggression.
A second study with 16 female participants replicated these findings even though the men's faces were presented for just 37 milliseconds each - barely long enough to be consciously detected.
The researchers aren't sure why wider faces are judged to be more aggressive, but one possibility is that a higher width-to-height ratio resembles the facial expression of anger, in which the face is widened and shortened. It's also possible that the width-to-height ratio correlates with some other cue that's used by observers to judge aggressiveness.
"The present results raise the possibility that subtle differences in facial structure influence trait judgements," the researchers said.
Carré JM, McCormick CM, & Mondloch CJ (2009). Facial Structure Is a Reliable Cue of Aggressive Behavior. Psychological science : a journal of the American Psychological Society / APS PMID: 19686297