An electrophysiological correlate of conflict processing in an auditory spatial Stroop task: the effect of individual...

Recent work has identified an event-related potential (ERP) component, the incongruency negativity (N(inc)), which is sensitive to auditory Stroop conflict processing. Here, we investigated how this index of conflict processing is influenced by individual differences in cognitive style. There is evidence that individuals differ in the strategy they use to navigate through the environment; some use a predominantly verbal-egocentric strategy while others rely more heavily on a spatial-allocentric strategy. In addition, navigational strategy, assessed by a way-finding questionnaire, is predictive of performance on an auditory spatial Stroop task, in which either the semantic or spatial dimension of stimuli must be ignored. To explore the influence of individual differences in navigational style on conflict processing, participants took part in an auditory spatial Stroop task while the electroencephalogram (EEG) was recorded. Whereas behavioral performance only showed a main effect of congruency, we observed the predicted three-way interaction between congruency, task type and navigational style with respect to our physiological measure of Stroop conflict. Specifically, congruency-dependent modulation of the N(inc) was observed only when participants performed their non-dominant task (e.g., verbal navigators attempting to ignore semantic information). These results confirm that the N(inc) reliably indexes auditory Stroop conflict and extend previous results by demonstrating that the N(inc) is predictably modulated by individual differences in cognitive style.