When more is less: doubt, repetition, memory, metamemory, and compulsive checking in OCD.

Memory and metamemory phenomena associated with obsessive-compulsive disorder (OCD) have received much attention in literature dedicated to a better understanding of the doubt and repetition associated with obsessions and compulsions. Following previous work on repeated checking among nonclinical participants, we asked participants to repeatedly turn on, turn off and check a real kitchen stove (n = 30 compulsive checkers diagnosed with OCD and n = 30 non-clinical undergraduates), or a real kitchen faucet (n = 30 non-clinical undergraduates) in a standardized, ritualized manner, in two connected experiments. Results indicated that following repeated relevant checking, both clinical and nonclinical participants reported significantly reduced memory confidence, vividness and detail; those who completed repeated irrelevant checking did not. The effects of repeated checking on memory accuracy were also explored. Results are discussed in terms of cognitive-behavioural formulations of OCD and in terms of the effects of repetition on memory and metamemory in association with checking behaviour.