Functional sex differences and signal forms have coevolved with conflict.
D Vaughn BeckerShelli L DubbsPublished in: The Behavioral and brain sciences (2019)
Evolutionary theory makes further predictions about conflict. It predicts sex differences in the proclivity to attack and defend. It further suggests complementary biases in what we expect of the sexes. Finally, it suggests that the forms of human facial expressions of anger and happiness may have coevolved with the regularity of conflict as a means of signaling, bluffing, and defusing attack.