Not all checking decreases memory confidence: Implications for obsessive-compulsive disorder.

BACKGROUND AND OBJECTIVES: Repetitive checking, a frequently reported compulsive behavior associated with obsessive-compulsive disorder (OCD), may, at least in part, result from a lack of memory confidence. Surprisingly, numerous studies have shown that when participants repeatedly perform an action and check that they performed it correctly, memory confidence decreases across repetitions, suggesting that repeated checking produces memory distrust. It is not clear, however, whether the checking component of each trial is critical for the decrease in confidence to occur. Five experiments tested whether the checking component is either necessary or sufficient to produce memory distrust.

METHODS: Participants repeatedly turned on and off virtual stove burners, with some conditions checking that the burners were off on each trial. Memory for the specific burners turned on and off was tested on the first and last trials, along with memory confidence.

RESULTS: Confidence decreased across trials even when the checking component was eliminated. However, increasing the number of times each person checked on each trial did not decrease confidence.

LIMITATIONS: A sample of individuals formally diagnosed with OCD was not tested. Also, our results only speak to massed (within-trial) checking, not spaced checking occurring over longer time intervals.

CONCLUSIONS: Whereas we consistently replicated the increase in memory distrust across repeated trials that is typically found with the stove-checking task, the checking component of each trial is neither necessary nor sufficient for the accrual of memory distrust. The build-up of proactive interference across repeated trials may cause the memory distrust.