A third potential mechanism for alcohol’s reduction of the ERN posited in previous theoretical accounts (see Holroyd & Yeung, 2003; Yeung & Cohen, 2006) is that alcohol impairs visual perception, making it difficult for drinkers to identify targets and therefore to know whether their responses are incorrect. Although both uncertainty about the accuracy of one’s response (Scheffers & Coles, 2000) and impaired target perception (see Yeung et al., 2007) can reduce ERN amplitude, the fact that alcohol did not impair overt error detection here makes it unlikely that target perception was impaired, and thus these likely are not the reasons for alcohol’s effects on the ERN. It should be noted, however, that at substantially higher doses alcohol might impair stimulus perception and/or error detection. Still, the current work casts doubt on these mechanisms as explanations for effects of alcohol occurring at or near the legal limit for intoxication.
