The effect of physical cleaning on threatened morality in individuals with obsessive-compulsive disorder

The association between morality and physical cleansing has been demonstrated in a series of studies by Zhong and Liljenquist. We predicted that this association would be especially prominent in people with obsessive-compulsive disorder (OCD). Participants with OCD and matched control participants wrote about an immoral deed they had committed, after which half of the participants in each group cleaned their hands with a wipe. All participants were then offered an opportunity to help a fictitious graduate student by taking part in her experiment. Replicating previous findings, physical cleaning reduced the willingness to help and relieved moral emotions. As predicted, this effect was particularly prominent among participants with OCD. We discuss two processes that may account for the association between morality and cleanliness in general and particularly in the context of OCD: embodiment of morality in terms of physical cleanliness and assigning abstract meaning to the physical actions of cleaning.