Recent experimental studies in cognitive science report the influence of “disgust” and “cleanliness” manipulations on moral judgment, yet little attention has been given to interpreting these studies together or developing models of the causal influence of cleanliness and disgust manipulations on moral judgment. I propose considerations for the causal modeling of these effects. The conclusions are not decisive in favor of one theory of disgust and cleanliness, but suggest several distinct causal roles of disgust- and cleanliness-type manipulations. The incorrect views, (...) I argue, are those that posit causal effects from a single common cognitive mechanism for both disgust and cleanliness. (shrink)

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)