Chen-Bo Zhong's team, who invited 58 undergrads to a lab filled with spotless new equipment. Half the students were asked to clean their hands with an antiseptic wipe so as not to soil the shiny surfaces. Afterwards all the students rated the morality of six societal issues including pornography and littering. Those who'd wiped their hands made far harsher judgments than those who didn't.
It was a similar story in a follow-up study with hundreds of participants recruited via a nation-wide database. Those primed to feel clean by reading a short passage that began 'My hair feels clean and light. My breath is fresh ...' made far harsher moral judgements about 16 social issues compared with those primed to feel dirty by a passage beginning, 'My hair feels oily and heavy. My breath stinks ...'
A third study was identical to the second, except that after reading either the dirty or clean passage of text the 136 undergrad participants also ranked themselves against their peers on several factors including intelligence, attractiveness and moral character. As before, those primed with the clean text made more harsh moral judgements on social issues. Crucially, this association was entirely mediated by their having an inflated sense of moral virtuosity compared with their peers (by contrast, reading the clean vs. dirty text made no difference to self rankings on the other factors).
'Acts of cleanliness have not only the potential to shift our moral pendulum to a more virtuous self, but also license harsher moral judgement of others,' Zhong and his team concluded.
Zhong, C., Strejcek, B., & Sivanathan, N. (2010). A clean self can render harsh moral judgment. Journal of Experimental Social Psychology, 46 (5), 859-862 DOI: 10.1016/j.jesp.2010.04.003
Link to earlier related post: Your conscience really can be wiped clean.