Infants display sense of morality, justice, and bias
Source: 60 Minutes 
A series of studies conducted at Yale University's Baby Lab challenge the notion that humans are born as a blank slate and suggest instead that babies are born with an innate sense of morality, justice, and preference for people they perceive to be like themselves.
When presented with puppets who, in a recent show, were portrayed as being "nice" or "mean," more than 75 percent of five month olds reached out for the "nice" puppet, suggesting that they were wary of characters who displayed anti-social tendencies. Even at three months old, infants gazed longer at the "nice" puppet following the show, an action that has long been established to suggest preference and interest in preverbal infants.  

A second study identified some bias in infants, however. First, infants were asked to pick one of two snacks. Then, two puppets were shown enjoying one of the two snacks. Those same puppets were then used in a skit that once again featured "nice" and "mean" behavior. When the puppet perceived as "different" from the babies due to snack preference was treated in a mean fashion, the infants showed support for his attacker following the show, suggesting that the infants preferred those puppets who harmed "the other."

The scholars trace this internal bias to our species' evolution via natural selection. The researchers say that human infants are predisposed to divide the world into "us" and "them" categories.

Studies of older children suggest that society and parental nurturing can reduce this bias in children and that by the age of eight, generosity blooms and children in lab studies are likely to consider the needs of unknown others as equal, if not greater, than their own.