Event-related potential correlates of the extraverts' sensitivity to valence changes in positive stimuli.

This study investigated whether the human sensitivity to valence intensity changes in positive stimuli varies with extraversion. Event-related potentials were recorded for highly positive, moderately positive, and neutral stimuli while participants (extraverts and nonextraverts) performed a standard/deviant categorization task, irrespective of the emotionality of deviants. The results of extraverts showed larger P2 and P3 amplitudes during highly positive condition than during moderately positive condition which, in turn, elicited larger P2 than neutral condition. Conversely, nonextraverts showed no differences at both P2 and P3 components. Thus, extraverts, unlike less extraverted individuals, are sensitive to valence changes in positive stimuli, which may be underlain by certain biogenetic mechanism.