The recent research has shown that structure of a man’s face can define the level of aggressiveness. An international team of researchers has found that the basic temperament of a man can be assessed through width-to-height ratio of a man’s face. They found that large width-to-height ratio is related to aggressive temperament. It means that men with round face are more aggressive. Researchers have also found out that male sex hormone testosterone makes faces more circular. Earlier studies have shown that testosterone is behind aggressiveness in men.

McCormick of Brock University and colleagues analyzed the data collected from 90 sportsmen. Aggression level was measured through the number of penalty minutes per game. These penalties were assigned to players for violent acts including slashing, elbowing, fighting and so on during the game. Researchers found a significant connection between facial ratio and the number of penalty minutes per game.

Lead researcher Cheryl McCormick said, "(Our) findings suggest that people can make accurate inferences about others' personality traits and behavioral dispositions based on certain signals conveyed by the face."

The study also showed that there was no such connection in facial shape and aggression in women.