Natural selection works on the comparative advantage of genetic traits. Perhaps because of this, evolutionary theorists have tended to emphasize the competitive nature of social relations. But this paints a very incomplete picture. Social behavior in all highly social animals involves much more cooperation than competition or antagonism. If social life was entirely a Hobbesian free-for-all, there would be little reason for humans and other animals to seek each other out. Just as evolution results in competitive and aggressive behavior, it also results in the capacity for strong social bonds, parental devotion to children, affection, cooperation, empathy (in humans at least), and many other traits that support cohesive social groups.