Thursday, February 20, 2020 - Toulouse - Alberto Micheletti and co-authors Graeme Ruxton and Andy Gardner published a new study in Evolutionary Human Sciences suggesting that warfare and migration have influenced altruism differently in men and in women since the prehistoric era.

In recent years, scientists have shown great interest in how warfare between human groups might have driven high levels of cooperation in our societies. Nonetheless, the possibility that warfare might have influenced which sex is more altruistic and which sex receives more help has been neglected, up until now. 

HELPING MEN DURING TIME OF WARFARE IS ADVANTAGEOUS FOR BOTH MEN AND WOMEN

A team of researchers at the Institute for Advanced Study in Toulouse (France) and the University of St Andrews (Scotland) used evolutionary models to investigate these sex differences and discovered that warfare can play a key role. Alberto Micheletti explains “Cooperating with others in your social group can be advantageous, as these people are often your genetic relatives. At the same time, relatives living together compete harshly over resources and this discourages altruism. Warfare offers to men the opportunity to compete in other groups, with non-relatives. However, women do not have this chance because they generally do not go to war or enjoy its spoils. We found that, for this reason, it can be advantageous for both sexes to help men more than women.”

WOMEN MARRYING INTO FOREIGN SETTLEMENTS DRIVES 'BOY'S CLUBS'

The study also found that patterns of migration can influence altruism. While both men and women migrate, one sex tends to move more than the other in our species. Some evidence suggests that in prehistory, women migrated more while men stayed in the settlements where they were born. Alberto Micheletti says “This migration pattern would have resulted in groups where men were surrounded by close relatives. We found that this would have encouraged them to help others more than women. And, given the impact of warfare on competition, these groups could have acted as ‘boy’s clubs’, where men were both more altruistic and received more altruism than women.” But this is not the only possible outcome: the study also found that the reverse pattern – a ‘girls’ club’ – could have evolved if women moved to defeated groups or migrated less than men. Interestingly, some smaller non-state societies seem to show similar patterns.

Read the whole press release

Link to the published paper