According to an LA Times Op-Ed, even infants have a sense of morality:
Yale psychology professor Paul Bloom notes that "it is often beneficial for humans to work together … which means it would have been adaptive to evaluate the niceness and nastiness of other individuals." In groundbreaking research, he and his team found that infants in their first year of life demonstrate aspects of an innate sense of right and wrong, good and bad, even fair and unfair. When shown a puppet climbing a mountain, either helped or hindered by a second puppet, the babies oriented toward the helpful puppet. They were able to make an evaluative social judgment, in a sense a moral response.Or, maybe the infants were just hoping that the 'helpful puppet" would give them a free lunch?