Steven Pinker does an excellent job at describing some of the scientific research done on morality in a NY Times Magazine article.

Some of the interesting points he makes along the way:

Moral illusions exist: “… our heads can be turned by an aura of sanctity, distracting us from a more objective reckoning of the actions that make people suffer or flourish. It seems we may all be vulnerable to moral illusions the ethical equivalent of the bending lines that trick the eye on cereal boxes and in psychology textbooks.”

Moral decision making is being studied with new tools: “Moral intuitions are being drawn out of people in the lab, on Web sites and in brain scanners, and are being explained with tools from game theory, neuroscience and evolutionary biology.”

Moral decisions can be well defined: “Moralization is a psychological state that can be turned on and off like a switch, and when it is on, a distinctive mind-set commandeers our thinking. This is the mind-set that makes us deem actions immoral (“killing is wrong”), rather than merely disagreeable (“I hate brussels sprouts”), unfashionable (“bell-bottoms are out”) or imprudent (“don’t scratch mosquito bites”). … The first hallmark of moralization is that the rules it invokes are felt to be universal. … The other hallmark is that people feel that those who commit immoral acts deserve to be punished”

Culture wars are shaped by the question: is it a lifestyle choice or immoral?  “Much of our recent social history, including the culture wars between liberals and conservatives, consists of the moralization or amoralization of particular kinds of behavior. Even when people agree that an outcome is desirable, they may disagree on whether it should be treated as a matter of preference and prudence or as a matter of sin and virtue. … Until recently, it was understood that some people didn’t enjoy smoking or avoided it because it was hazardous to their health. But with the discovery of the harmful effects of secondhand smoke, smoking is now treated as immoral. Smokers are ostracized; images of people smoking are censored; and entities touched by smoke are felt to be contaminated (so hotels have not only nonsmoking rooms but nonsmoking floors). … At the same time, many behaviors have been amoralized, switched from moral failings to lifestyle choices. They include divorce, illegitimacy, being a working mother, marijuana use and homosexuality. Many afflictions have been reassigned from payback for bad choices to unlucky misfortunes.”

People match their moralization not just to a sense of harm, but to their own lifestyle.  “We don’t show contempt to the man who fails to change the batteries in his smoke alarms or takes his family on a driving vacation, both of which multiply the risk they will die in an accident. Driving a gas-guzzling Hummer is reprehensible, but driving a gas-guzzling old Volvo is not; eating a Big Mac is unconscionable, but not imported cheese or crème brûlée.”

There are a few themes that are universal to moral concerns across cultures.  “The exact number of themes depends on whether you’re a lumper or a splitter, but Haidt counts five — harm, fairness, community (or group loyalty), authority and purity — and suggests that they are the primary colors of our moral sense. Not only do they keep reappearing in cross-cultural surveys, but each one tugs on the moral intuitions of people in our own culture.”

People start with a moral conclusion based on a feeling, and then move toward a rationalization … and this may be heavily influenced by biology, itself shaped by Darwin’s natural selection.  “The five spheres are good candidates for a periodic table of the moral sense not only because they are ubiquitous but also because they appear to have deep evolutionary roots. The impulse to avoid harm, which gives trolley ponderers the willies when they consider throwing a man off a bridge, can also be found in rhesus monkeys, who go hungry rather than pull a chain that delivers food to them and a shock to another monkey. Respect for authority is clearly related to the pecking orders of dominance and appeasement that are widespread in the animal kingdom. The purity-defilement contrast taps the emotion of disgust that is triggered by potential disease vectors like bodily effluvia, decaying flesh and unconventional forms of meat, and by risky sexual practices like incest.”

Understanding these different moral spheres can help you understand foreigners or people of a different moral persuasion in your own culture.  “Many of the flabbergasting practices in faraway places become more intelligible when you recognize that the same moralizing impulse that Western elites channel toward violations of harm and fairness (our moral obsessions) is channeled elsewhere to violations in the other spheres. Think of the Japanese fear of nonconformity (community), the holy ablutions and dietary restrictions of Hindus and Orthodox Jews (purity), the outrage at insulting the Prophet among Muslims (authority). In the West, we believe that in business and government, fairness should trump community and try to root out nepotism and cronyism. In other parts of the world this is incomprehensible — what heartless creep would favor a perfect stranger over his own brother? … Many bones of contention, like homosexuality, atheism and one-parent families from the right, or racial imbalances, sweatshops and executive pay from the left, reflect different weightings of the spheres. In a large Web survey, Haidt found that liberals put a lopsided moral weight on harm and fairness while playing down group loyalty, authority and purity. Conservatives instead place a moderately high weight on all five. It’s not surprising that each side thinks it is driven by lofty ethical values and that the other side is base and unprincipled.”

Searching for an absolute morality is tough.  “Putting God in charge of morality is one way to solve the problem, of course, but Plato made short work of it 2,400 years ago. Does God have a good reason for designating certain acts as moral and others as immoral? If not — if his dictates are divine whims — why should we take them seriously? Suppose that God commanded us to torture a child. Would that make it all right, or would some other standard give us reasons to resist? And if, on the other hand, God was forced by moral reasons to issue some dictates and not others — if a command to torture a child was never an option — then why not appeal to those reasons directly?  This throws us back to wondering where those reasons could come from, if they are more than just figments of our brains.”

But there are reasons why morality should be adopted by rational creatures.

“One is the prevalence of nonzero-sum games. In many arenas of life, two parties are objectively better off if they both act in a nonselfish way than if each of them acts selfishly. You and I are both better off if we share our surpluses, rescue each other’s children in danger and refrain from shooting at each other, compared with hoarding our surpluses while they rot, letting the other’s child drown while we file our nails or feuding like the Hatfields and McCoys.  …

“The other external support for morality is a feature of rationality itself: that it cannot depend on the egocentric vantage point of the reasoner. … I can’t act as if my interests are special just because I’m me and you’re not, any more than I can persuade you that the spot I am standing on is a special place in the universe just because I happen to be standing on it.  … Not coincidentally, the core of this idea — the interchangeability of perspectives — keeps reappearing in history’s best-thought-through moral philosophies, including the Golden Rule (itself discovered many times); Spinoza’s Viewpoint of Eternity; the Social Contract of Hobbes, Rousseau and Locke; Kant’s Categorical Imperative; and Rawls’s Veil of Ignorance. It also underlies Peter Singer’s theory of the Expanding Circle — the optimistic proposal that our moral sense, though shaped by evolution to overvalue self, kin and clan, can propel us on a path of moral progress, as our reasoning forces us to generalize it to larger and larger circles of sentient beings.”

His conclusions are worth emphasizing:

“At the very least, the science tells us that even when our adversaries’ agenda is most baffling, they may not be amoral psychopaths but in the throes of a moral mind-set that appears to them to be every bit as mandatory and universal as ours does to us. …

“The moral sense, we are learning, is as vulnerable to illusions as the other senses. It is apt to confuse morality per se with purity, status and conformity. It tends to reframe practical problems as moral crusades and thus see their solution in punitive aggression. It imposes taboos that make certain ideas in-discussible. And it has the nasty habit of always putting the self on the side of the angels. … People have shuddered at all kinds of morally irrelevant violations of purity in their culture: touching an untouchable, drinking from the same water fountain as a Negro, allowing Jewish blood to mix with Aryan blood, tolerating sodomy between consenting men. And if our ancestors’ repugnance had carried the day, we never would have had autopsies, vaccinations, blood transfusions, artificial insemination, organ transplants and in vitro fertilization, all of which were denounced as immoral when they were new. …

And finally:

“Our habit of moralizing problems, merging them with intuitions of purity and contamination, and resting content when we feel the right feelings, can get in the way of doing the right thing.”

You can find the entire article here:  http://www.nytimes.com/2008/01/13/magazine/13Psychology-t.html?ei=5088&en=21ff00bccd4e9e91&ex=1357880400&partner=rssnyt&emc=rss&pagewanted=all