No matter how hard men try, they may not be able to hide their aggression. A study in male ice-hockey players suggests that to gauge a man’s aggression levels, you just have to look at the proportions of his face.
Cheryl McCormick and Justin Carre from Brock University in Ontario, Canada, found that the larger the width-to-height ratio of a player’s face, the more aggressive they were. Link to Article
Source: NewScientist, Aug 20 2008