According to Haidt's research humans possess six universal moral modules, or moral "foundations," that get built upon to varying degrees across culture and time. They are: Care/harm, Fairness/cheating, Loyalty/betrayal, Authority/subversion, Sanctity/degradation, and Liberty/oppression. Haidt describes these six modules like a "tongue with six taste receptors." "In this analogy," he explains in the book, "the moral matrix of a culture is something like its cuisine: it’s a cultural construction, influenced by accidents of environment and history, but it’s not so flexible that anything goes. You can’t have a cuisine based on grass and tree bark, or even one based primarily on bitter tastes. Cuisines vary, but they all must please tongues equipped with the same five taste receptors. Moral matrices vary, but they all must please righteous minds equipped with the same six social receptors."​