He outlines six, cross-cultural foundations of morality.
- Care/harm: cherishing and protecting others.
- Fairness/cheating: rendering justice according to shared rules.
- Liberty/oppression: the loathing of tyranny.
- Loyalty/betrayal: standing with your group, family, nation.
- Authority/subversion: obeying tradition and legitimate authority.
- Sanctity/degradation: abhorrence for disgusting things, foods, actions.
He's pretty clear that Liberal morality not only emphasizes the first three but limits its moral imagination to them. Conservatives, although they give different colorings to the first three, see all six as important to morality.
The result of his tests show that while Conservatives can put themselves in the place of Liberals and accurately imagine that world, describing it in the same terms that Liberals do, Liberals fail badly at even being able to take the second triad of values as anything other than forms of evil.
This explains the failure of a lot of Left-Right "conversations".
As he goes on to point out, people live inside stories far more than they live inside intellectual propositions. Any therapist can tell you that. And the Left story and the Right story do not mesh.