Chen-Bo Zhong and Katie Liljenquist first demonstrated that the two concepts really are linked in our minds. Participants asked to recall a recent unethical deed they had committed were subsequently more likely to convert word fragments (e.g. W__H) into a cleansing-related word (e.g. WASH vs. WISH) than were participants who recalled something ethical they had done.
Furthermore, participants who recalled an unethical deed were more likely than participants who recalled an ethical deed (67 per cent vs. 33 per cent), to choose an antiseptic wipe as a free gift rather than a pencil.
And it seems physical cleansing can actually clear our moral conscience. A different set of participants were again asked to describe something unethical they had done in the past. Some of them were then offered an antiseptic wipe to clean their hands. Next, all the participants were asked to volunteer to help a research student who desperately needed participants. Remarkably, fewer of the participants who’d wiped their hands clean volunteered – 41 per cent of them did compared with 74 per cent of the participants who hadn’t cleaned their hands. Apparently, their moral stains having been washed away, the participants who’d cleaned their hands subsequently felt less of a compulsion to compensate for their previous unethical deed.
The findings raise intriguing questions about the effect washing might have on people’s future moral behaviour. “Would cleansing ironically license unethical behaviour?”, the researchers asked. “It remains to be seen whether clean hands really do make a pure heart, but our studies indicate that they at least provide a clean conscience after moral trespass” they said.
Zhong, C-B. & Liljenquist, K. (2006). Washing away your sins: Threatened morality and physical cleansing. Science, 313, 1451-1452.