Tangentially related to my post last week about treating children as people, Paul Bloom @ The New York Times Magazine discusses current research into how human beings acquire morality (or if they are born wired, so to speak, with a sense of justice and injustice)
Morality, then, is a synthesis of the biological and the cultural, of the unlearned, the discovered and the invented. Babies possess certain moral foundations — the capacity and willingness to judge the actions of others, some sense of justice, gut responses to altruism and nastiness. Regardless of how smart we are, if we didn’t start with this basic apparatus, we would be nothing more than amoral agents, ruthlessly driven to pursue our self-interest. But our capacities as babies are sharply limited. It is the insights of rational individuals that make a truly universal and unselfish morality something that our species can aspire to.
I don't necessarily agree with all of the ways he defines moral and immoral sentiments and actions, but it is an interesting overview of some of the more recent theories vis a vis how we construct a mutually agreed upon moral framework in which to operate as a human society.