Box 2. The basis of belief

Although disgust may be built into the human moral faculty, that faculty does not work the same way in everyone, and the moral weight given to repugnance may thus differ from person to person. Paul Bloom from Yale University, working with David Pizarro and Yoel Inbar at Cornell University, Ithaca, New York, has recently explored how reactions to disgust relate to political and ideological views of the world. Their results bring into focus the fault lines of the notorious 'culture wars' that divide liberals and conservatives on myriad social issues.

In an unpublished study, Bloom and his colleagues asked self-identified political liberals and conservatives to take a well-established written test for measurement of sensitivity to disgust, and then recorded their attitudes on a range of moral and social issues. They found that, even when controlling for factors such as age, class and gender, the more prone to disgust a person was, the more he or she was likely to hold conservative views on social debates. The link was especially strong in attitudes to abortion and gay rights, both of which are potentially rich in the type of imagery that can prompt visceral disgust. On the more abstract concepts, the link between sensitivity to disgust and conservatism was not statistically significant for any given issue, but when the issues were aggregated it became so, according to Inbar. Pizarro says he has preliminary data suggesting sensitivity to disgust is also related to attitudes to cloning and stem-cell research.

This finding fits with work by psychologist Jonathan Haidt and graduate student Jesse Graham from the University of Virginia in Charlottesville, on the foundations of the moral faculty. A psychological tradition that draws on the work of Lawrence Kohlberg — known for his work in moral development — portrays morality as consisting of two central issues: whether someone was treated unfairly and whether someone was harmed. Then, in the late 1980s, anthropologist Richard Shweder developed the idea that ethical concepts around the world cluster into three overlapping but distinct domains — the ethics of autonomy (individual rights and freedom from harm), community (respect for tradition, hierarchy and authority) and divinity (spiritual purity and sanctity). Haidt and Graham, drawing on both lines of work, have suggested five foundations to explain the ethical intuitions observed across cultures: a concern for harm to people; fairness; in-group loyalty; respect for authority; and spiritual purity and sanctity. Disgust, they think, is most closely tied to the last of these.

Haidt and Graham used a questionnaire to probe 1,613 self-identified liberals and conservatives about the weight they gave to these different concerns in their moral judgements⁶. Respondents were asked to rate the relevance of 15 such concerns (three for each foundation) in making moral judgements, such as "Was anyone harmed?", "Did someone act unfairly?" or "Did someone betray the in-group?". Whereas liberals typically draw on just the first two foundations — harm and fairness — conservatives tend to be concerned with all five. "Liberals see only a subset of the moral domain — there's a lot more going on that they're not aware of," says Haidt. "We liberals often find it difficult to understand what the big deal is about homosexuality and even first-trimester abortion. But there's more to morality than we used to think — the areas of sacredness and divinity, and group-loyalty have barely been touched."

 G. HERBERT/AP

D.J.