Commentator Bill O Reilly checks himself in mirror before interview at Republican National Convention.
Television commentator Bill O'Reilly checks himself in a mirror (Reuters)

Forget the battle of the sexes when it comes to narcissism as men win hands down, a new study has revealed.

Data from almost half a million people, collected by the University at Buffalo School, shows males on average scored higher on the educational institute's narcissism tests.

"Narcissism is shown to boost self-esteem, emotional stability and the tendency to emerge as a leader. By examining gender differences in narcissism, we may be able to explain gender disparities in these important outcomes," says lead author of the study Emily Grijalva, PhD, assistant professor of organisation and human resources in the UB School of Management.

The study, which is to be published in the Psychological Bulletin, was compiled by studying 31 years' worth of research on the subject, examining more than 350 journal articles, dissertations, manuscripts and technical manuals and then looking at three defining aspects of narcissism; leadership and authority, grandiose and exhibitionism and entitlement.

The widest gap was seen in entitlement and found that men are more likely to exploit others for their personal gain, and feel that they are deserving of certain privileges.

Leadership and authoritativeness was the second widest and saw that men are likely to be more assertive and seek power.

"But there was no difference in the exhibitionism aspect, meaning both genders are equally likely to display vanity or self-absorption," Grijalva said.

However, she said these differentiations in personalities can arise from a young age when gender stereotypes are enforced.

Grijalva added: "Individuals tend to observe and learn gender roles from a young age, and may face backlash for deviating from society's expectations. In particular, women often receive harsh criticism for being aggressive or authoritative, which creates pressure for women, more so than for men, to suppress displays of narcissistic behaviour."