A study spanning three decades and involving the responses of nearly half a million individuals has concluded that although humans are in general an incredibly vain species, males are considerably more narcissistic than their female counterparts. The reasoning for this, however, lies more in social constraints than biological predisposition.

In the study conducted at University at Buffalo School of Management, a team led by Emily Grijalva questioned 475,000 participants over the span of 31 years to determine their level of narcissistic behavior, a recent press release reported. Narcissism is defined as an excessive or erotic interest in oneself and one's physical appearance. In small doses, the trait is beneficial, but in large quantities, it can be classified as a personality disorder.

For the study, the individuals were asked questions to help determine their level of leadership/authority, grandiose/exhibitionism, and entitlement. They were also asked to respond how closely they agreed with statements like: “I like having authority over people” and “I insist upon getting the respect that is due to me.”

Results showed that there was no difference between genders, ages, or even generation in the grandiose/exhibitionism category. This is good news for the millennial “selfie” generation, who often get the bad reputation as being self-absorbed. As suggested by this study, 20-somethings are just as self-absorbed as earlier generations, but they just show it differently.

The widest gap of difference was found in the entitlement category, suggesting that men of all ages and walks of Earth are more likely to exploit others than women, and to feel entitled to certain privileges. There were also considerable differences in gender when it came to the leadership/authority category.

“Compared with women, men exhibit more assertiveness and desire for power," Grijalva said in the press release.

The team believes that the reason for the discrepancy in narcissism in the sexes is not exactly because the boys were taught to learn the trait but rather that little girls were taught to suppress it.

"Individuals tend to observe and learn gender roles from a young age and may face backlash for deviating from society's expectations," Grijalva said. "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 behavior."

Future studies will investigate the extent that social, cultural, and biological factors play in the contribution of gender-based personalities. For now, the present findings are food for thought as to whether being told to not be “bossy” as a young girl has prevented some women from yearning for leadership roles in adulthood.

Source: Grijalva E, Newman DA, Tay L, et al. Gender differences in narcissism: A meta-analytic review. Psychological Bulletin. 2015.