It is common knowledge that men are more likely to have psychopathic tendencies than women. For example, one study on a prison population found 31% of men met the criteria, compared to only 11% of women.

Psychopathy has a number of higher-order dimensions, including Self-centered Impulsivity, Heartlessness, and Fearless Dominance. The first dimension, Self-centered Impulsivity, is associated with impetuosity, belligerence, and narcissism. 

Heartlessness is related to an inability to experience important social emotions like love or remorse. 

Psychopaths, who clearly lack empathy, are at a disadvantage — or so the thinking goes. However, empathy requires taking other people's feelings into consideration, walking in their shoes, so to speak. Walking requires energy.