The effect of manipulating task difficulty on error-related negativity in individuals with obsessive-compulsive symptoms.

Previous research has found that individuals with obsessive-compulsive (OC) symptoms show larger error-related negativity (ERN) and correct-response negativity (CRN) amplitudes than controls. Task difficulty was manipulated during a flanker task and a probabilistic learning task to determine the effect of difficulty on ERN and CRN amplitudes in those with high or low levels of OC symptoms. Increasing task difficulty during a flanker task attenuated ERN amplitudes and enhanced CRN amplitudes. Although larger ERN amplitudes were found in the high OC group compared to the low OC group during the easy flanker task, this group difference was no longer apparent during the difficult version of the flanker task. Increasing difficulty during the probabilistic learning task had no effect on group differences in ERN or CRN amplitudes. The results of this study suggest that the hyperactive error-monitoring activity associated with OC symptoms depends on the difficulty and type of task performed.