Cleanliness Reduces the Severity of Moral Judgments

Theories of moral judgment have long emphasized reasoning and conscious thought while downplaying the role of intuitive and contextual influences. However, recent research has demonstrated that incidental feelings of disgust can influence moral judgments and make themmore severe. This study involved two experiments demonstrating that the reverse effect can occur when the notion of physical purity is made salient, thus making moral judgments less severe. After having the cognitive concept of cleanliness activated (Experiment 1) or after physically cleansing themselves after experiencing disgust (Experiment 2), participants found certain moral actions to be less wrong than did participants who had not been exposed to a cleanliness manipulation. The findings support the idea that moral judgment can be driven by intuitive processes, rather than deliberate reasoning. One of those intuitions appears to be physical purity, because it has a strong connection tomoral purity. Many cultures equate physical cleanliness with moral and spiritual purity. For example, many religious practices require that one first engage in physical cleansing, such as washing parts of one’s body. Haidt and colleagues (e.g., Haidt & Joseph, 2008) have proposed that the notion of purity constitutes a basic moral intuition that developed from the need to safeguard oneself from potentially harmful substances. According to this approach, disgust evolved as an emotion to protect the body from germs, parasites, and spoilt food, but it was then extended to social and moral domains (Rozin, Haidt, & McCauley, 2000). As a consequence, people often report finding immoral acts disgusting. Indeed, similar neural structures appear to be involved in the experience of physical and moral disgust (Moll et al., 2005). Recent studies have demonstrated that experimentally induced feelings of disgust can attach themselves to moral judgments, leading the person to conclude that a particular moral action is quite wrong (Schnall, Haidt, Clore, & Jordan, 2008; see also Wheatley & Haidt, 2005). Physical disgust was induced by exposure to a bad smell, working in a disgusting room, recalling a physically disgusting experience, or a video induction. In each case, the results showed that disgust can increase the severity of moral judgments in comparison with those made in control conditions, and this effect applied irrespective of whether the action to be judged was itself physically disgusting or not. In contrast to disgust, induced sadness did not influence moral judgments. These studies showed that moral judgments can be based on intuitive emotional feelings rather than on rational reasoning processes (Haidt, 2001; Prinz, 2006), even when the feeling of disgust was irrelevant to the moral action under consideration. On the flip side of disgust, the association between physical and moral purity in Western cultures was recently demonstrated by Zhong and Liljenquist (2006). After recalling a moral transgression from their own lives, participants weremore likely to think of cleansing-related words, and they showed a desire to engage in cleansing behavior. The two experiments reported in this article investigated the reverse relationship: If cleansing behavior can ‘‘wash away one’s sins,’’ as Zhong and Liljenquist (2006) demonstrated, then the feeling of cleanliness should reduce the perceived seriousness of moral transgressions and also ‘‘wash away other people’s sins.’’ Following research showing that concepts of cleanliness can be primed in subtle ways (Holland, Hendriks, & Aarts, 2005), the first experiment activated concepts of cleanliness and asked participants to rate how wrong certain moral actions were. Because the sense of purity from the priming should be misattributed to the moral judgments, it was expected that priming with cleanliness words would reduce the severity of moral judgments more so than would priming with neutral control words.