This week I will be blogging on Sarah Blaffer Hrdy's Mothers and Others: The Evolutionary Origins of Mutual Understanding. Her concern is figuring out how human beings evolved the capacity to share childrearing - what she calls alloparenting - with others who are not mother or father to the baby. The "it takes a village to raise a child" strategy is very helpful for humans, and very different from what is normal to the Great Apes.
Hrdy argues that empathy and giving are hard-wired in us. We can see from brain scans that people find helping others inherently rewarding. One of the most striking findings that she reports is that people are more cooperative than economists assume: in a one-shot Prisoner’s Dilemma game, 42% cooperate anyway. In multiple iterations of the game, when we can see who is generous and who is not, the cooperative people tend to get even more trusting and cooperative.
A crucial point that I take from these experiments is that we want to be cooperative. We are very sensitive to who else is cooperative, and whether the social environment makes cooperation normal. If the people we most depend on are reliable, and most people we deal with are, too, then we tend to be cooperative and trusting in new situations because that is the kind of person we want to be - even though we might get suckered.
On the other hand, children who are betrayed by adults have a much harder time trusting and cooperating.