Characterizing switching and congruency effects in the Implicit Association Test as reactive and proactive cognitive control.

Recent research has identified an important role for task switching, a cognitive control process often associated with executive functioning, in the Implicit Association Test (IAT). However, switching does not fully account for IAT effects, particularly when performance is scored using more recent d-score formulations. The current study sought to characterize multiple control processes involved in IAT performance through the use of event-related brain potentials (ERPs). Participants performed a race-evaluative IAT while ERPs were recorded. Behaviorally, participants experienced superadditive reaction time costs of incongruency and task switching, consistent with previous studies. The ERP showed a marked medial frontal negativity (MFN) 250-450 ms post-stimulus at midline fronto-central locations that were more negative for incongruent than congruent trials but more positive for switch than for no-switch trials, suggesting separable control processes are engaged by these two factors. Greater behavioral IAT bias was associated with both greater switch-related and congruency-related ERP activity. Findings are discussed in terms of the Dual Mechanisms of Control model of reactive and proactive cognitive control.