Confirmed: War is caused by men's sex drive

The findings, which support the ‘male warrior hypothesis’, are published in the journal Philosophical Transactions of the Royal Society B.

The psychologists claim that in all cultures and throughout history, men have sought to get their way by initiating violence.

They prefer group-based hierarchies and are identified more strongly with their own groups than women.

At a basic level, such ‘tribal’ aggression helped men in a group to obtain more females, increasing their chances of reproduction.