Social intuitionism

Social intuitionism is a movement in moral psychology that arose in contrast to more heavily rationalist theories of morality, like that of Lawrence Kohlberg. Kohlberg developed a model of moral reasoning that he claimed accounts for people's moral behavior. More sophisticated reasoning, he asserted, should lead one to more consistent moral action, because one realizes that moral principles are prescriptive in nature and so demand action from the self.

Jonathan Haidt (2001) greatly de-emphasizes the role of reasoning in reaching moral conclusions. Moral judgment is primarily given rise to by intuition with reasoning playing a very marginalized role in most of our moral decision-making. Conscious thought-processes serves as a kind of post hoc justification of our decisions--that is, after the moral decision has been made.

His main evidence comes from studies of "moral dumbfounding" where people have strong moral reactions but fail to establish any kind of rational principle to explain their reaction. Imagine that a brother and sister slept together once, no one else knew, no harm befell either one, and both felt it brought them closer as siblings. Many people still have a very strong negative reaction to this story, yet they can't explain why using Kohlberg's principled moral reasoning. Haidt suggests that we have unconscious, affective, moral heuristics that guide our reactions to morally charged situations and our moral behaviour, and that if we are asked to reason we do so only after we have made the decision.