Man & Woman
© Debrocke Classic Stock / Getty Images
Women score consistently more highly than men on moral dimensions of caring, fairness and purity, according to a comprehensive, cross-cultural study of gender differences in morality published in the journal Proceedings of the Royal Society B.

While the differences were robust, the study found they were stronger in more flexible, individualistic cultures with greater gender equality. Other moral dimensions of loyalty and authority, on the other hand, showed negligible and highly variable sex differences.

These dimensions are thought to be psychologically innate and then moulded by culture.

"Each moral system produces fast, automatic gut-level reactions of like or dislike when certain phenomena are perceived in the social world," write Mohammad Atari and colleagues from the University of Southern California, US, "which in turn guide judgements of right and wrong".

"These systems, according to [the theory], have evolutionarily adaptive underpinnings present in all individuals."

They are: care, aversion to the suffering of others; fairness, based on ideas of justice, rights and autonomy; loyalty to our tribe or group; authority, supporting the merits of leadership and respect for traditions; and spiritual purity.

Care and fairness are considered to embody individual wellbeing while loyalty, authority and purity embrace the importance of community, group bonds and social order.

Gender differences in morality are thought to have evolved to adapt to different roles - women as being caring and compassionate to protect offspring, for instance, or valuing purity to protect monogamous relationships.

"It is important to women to invest resources in creating and maintaining supportive social networks in order to protect themselves and their offspring," the authors note.

"For men, it can sometimes be attractive to invest their resources in forming coalitions to engage in intergroup aggression, as the spoils of an intergroup victory enhance their mating opportunities substantially."

The fact that sex differences in the care factor dropped markedly in collectivist cultures could be explained by higher ratios of men to women, the researchers suggest.

"In these contexts, men are more likely to focus on family values, long-term relationships, parenting and caring for offspring since opportunities for short-term mating are scarce."

The primary study involved an anonymous online survey of more than 330,000 people from 67 countries, providing feedback on their own morality, ethics and values.

The findings were confirmed by secondary analysis in nearly 12,000 people from 19 countries in an independent data collected from other researchers.