In addition to the response-locked ERN, two stimulus-locked ERP components—the N2 and frontal slow wave (FSW)—are thought to index processes associated with conflict monitoring and performance adjustment, respectively. The N2 is a transient negativity over frontal and frontal-central scalp sites, peaking between 200–350 ms after stimulus onset (see van Veen & Carter, 2002; Yeung et al., 2004). The N2 is highly sensitive to response conflict (e.g., larger during incompatible than compatible flanker trials; Kopp, Rist, & Mattler, 1996), and, similar to the ERN, source localization indicates that the N2 originates in the ACC (van Veen & Carter, 2002; Yeung et al., 2004). Research examining correct-trial performance has shown no effects of alcohol on N2 amplitude (Bartholow et al., 2006; Easdon, Izenberg, Armilio, Yu, & Alain, 2005; Ridderinkhof et al., 2002; Rohrbaugh et al., 1987). No previous study has tested whether the N2 (and the conflict-monitoring process it reflects) is differentially affected by alcohol as a function of trial-to-trial fluctuations in performance, however. In the current study, consistent with the idea that alcohol’s impairment of control can be characterized in terms
