The spontaneous decay and persistence of mental contamination: An experimental analysis

Background and objectives It has recently been identified that feelings of contamination can arise in the absence of physical contact with a stimulus. This concept, known as ‘mental contamination’ has particular relevance to Obsessive Compulsive Disorder in which compulsive cleaning is a common symptom presentation. Experimental studies have begun to examine the psychopathology of mental contamination. The aims of the two experiments reported here were to explore the evocation and spontaneous decay of mental contamination. Methods In Experiment 1, a variant of the autobiographical memory task was used in which 40 non-clinical participants were asked to recall autobiographical memories associated with betrayal, harm, humiliation and violation of moral standards. In Experiment 2, 60 participants with moderate levels of mental contamination were asked to complete five short tasks designed to induce mental contamination, including recalling unwanted memories and images. Results In both experiments, participants reported significant increases in mental contamination, anxiety, urges to wash and actual washing behaviour. In experiment 1, the effect of the induction decayed spontaneously. Experiment 2 found that re-evoking contamination and repeated washing led to the persistence of mental contamination. Limitations The studies were conducted on non-clinical samples. Conclusions These findings demonstrated that repeated triggers may be causally connected to the maintenance of mental contamination fears in non-clinical samples.