[n4r9]

I think children are constantly experiencing rewards and punishments of a sort analagous to reinforcement learning. Until a certain age their brain is hardwired to want to please their parents, so they pay a lot of attention to the parents' faces, and find reward in smiles and find punishment in frowns. After that, they are driven by a certain amount of ego, and find reward in self-accomplishment and find punishment in being told what to do.