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.

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. Haidt asks us to consider how much money someone would have to pay us to do hypothetical acts like the following:

1 - Stick a pin into your palm.
Stick a pin into the palm of a child you don’t know. (Harm.)

2 - Accept a wide-screen TV from a friend who received it at no charge because of a computer error.
Accept a wide-screen TV from a friend who received it from a thief who had stolen it from a wealthy family. (Fairness.)

3 - Say something bad about your nation (which you don’t believe) on a talk-radio show in your nation.
Say something bad about your nation (which you don’t believe) on a talk-radio show in a foreign nation. (Community.)

4 - Slap a friend in the face, with his permission, as part of a comedy skit.
Slap your minister in the face, with his permission, as part of a comedy skit. (Authority.)

5 - Attend a performance-art piece in which the actors act like idiots for 30 minutes, including flubbing simple problems and falling down on stage.
Attend a performance-art piece in which the actors act like animals for 30 minutes, including crawling around naked and urinating on stage. (Purity.)

In each pair, the second action feels far more repugnant.