Psychological research has been discovering a number of puzzling features of morality and moral cognition recently.2 Zhong & Liljenquist (2006) found that when people are asked to think about an unethical deed or recall one they themselves have committed in the past, issues of physical cleanliness become salient. Zhong & Liljenquist cleverly designate this phenomenon the “Macbeth Effect,” and it takes some interesting forms. For instance, reading a story describing an immoral deed increased people’s desire for products related to cleansing, (...) like a shower soap, disinfectants, or antiseptic wipes. Moreover, Zhong & Liljenquist found that cleaning one’s hands after describing a past unethical deed actually reduced moral emotions such as guilt and shame. So much so that those who did “wash away their sins” were less likely than other participants to help out a.. (shrink)