This is an excellent paper that introduces Jonathan Haidt's social intuitionist theory of moral judgment. It is rather long, but well worth the read. The PDF is attached. - Dallas

The Emotional Dog and Its Rational Tail: A Social Intuitionist Approach to Moral Judgment

Research on moral judgment has been dominated by rationalist models, in which moral judgment is thought to be caused by moral reasoning. The author gives 4 reasons for considering the hypothesis that moral reasoning does not cause moral judgment; rather, moral reasoning is usually a post hoc construction, generated after a judgment has been reached. The social intuitionist model is presented as an alternative to rationalist models. The model is a social model in that it deemphasizes the private reasoning done by individuals and emphasizes instead the importance of social and cultural influences. The model is an intuitionist model in that it states that moral judgment is generally the result of quick, automatic evaluations (intuitions). The model is more consistent than rationalist models with recent findings in social, cultural, evolutionary, and biological psychology, as well as in anthropology and primatology.

Here are a few quotes I especially liked:

Intuitionism in philosophy refers to the view that there are moral truths and that when people grasp these truths they do so not by a process of ratiocination and reflection but rather by a process more akin to perception, in which one "just sees without argument that they are and must be true". Thomas Jefferson's declaration that certain truths are "self-evident" is an example of ethical intuitionism. Intuitionist approaches in moral psychology, by extension, say that moral intuitions (including moral emotions) come first and directly cause moral judgments. Moral intuition is a kind of cognition, but it is not a kind of reasoning.

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They argued that people have a built-in moral sense that creates pleasurable feelings of approval toward benevolent acts and corresponding feelings of disapproval toward evil and vice. David Hume in particular proposed that moral judgments are similar in form to aesthetic judgments: They are derived from sentiment, not reason, and we attain moral knowledge by an "immediate feeling and finer internal sense," not by a "chain of argument and induction".

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The thrust of Hume's attack on rationalism was that reason alone cannot accomplish the magnificent role it has been given since Plato. Hume saw reason as a tool used by the mind to obtain and process information about events in the world or about relations among objects. Reason can let us infer that a particular action will lead to the death of many innocent people, but unless we care about those people, unless we have some sentiment that values human life, reason alone cannot advise against taking the action. Hume argued that a person in full possession of reason yet lacking moral sentiment would have difficulty choosing any ends or goals to pursue and would look like what we now call a psychopath.

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The illusions of moral judgment. If moral reasoning is generally a post hoc construction intended to justify automatic moral intuitions, then our moral life is plagued by two illusions. The first illusion can be called the wag-the-dog illusion: We believe that our own moral judgment (the dog) is driven by our own moral reasoning (the tail). The second illusion can be called the wag-theother-dog's-tail illusion: In a moral argument, we expect the successful rebuttal of an opponent's arguments to change the opponent's mind. Such a belief is like thinking that forcing a dog's tail to wag by moving it with your hand will make the dog happy.

The wag-the-dog illusion follows directly from the mechanics of the reasoning process described above. Pyszczynski and Greenberg (1987) point out that by going through all the steps of hypothesis testing, even though every step can be biased by selfserving motivations, people can maintain an "illusion of objectivity" about the way they think. The wag-the-dog illusion may therefore be one of the mechanisms underlying naive realism, the finding that people think that they see the world as it is whereas their opponents in a moral dispute are biased by ideology and self-interest.