BIOELECTRICAL ECHOES FROM EVALUATIVE CATEGORIZATIONS .1. A LATE POSITIVE BRAIN POTENTIAL THAT VARIES AS A FUNCTION OF TRAIT NEGATIVITY AND EXTREMITY

Attitudes can be conceptualized in terms of the elementary operations of evaluative categorization and response selection-execution. This ar ticle describes a component of the event-related potential that is ass ociated with the first of these operations. Ss were exposed to sequenc es of 6 traits and performed a dichotomous evaluative categorization t ask. Evaluative inconsistency was varied by embedding very positive, m oderately positive, moderately negative, and very negative traits in s equences containing predominantly very positive traits. Highly and mod erately evaluatively inconsistent traits, compared with mildly inconsi stent or consistent traits, evoked a larger amplitude late positive po tential (LPP) that was maximal over centroparietal regions. Furthermor e, extremely evaluatively inconsistent traits evoked a larger amplitud e LPP than moderately evaluatively inconsistent traits even though bot h sets of traits were judged to be negative.