Autonomic activity and reaction time in relation to extraversion and behavioral impulsivity in children and adolescents

Abstract

Children and adolescents ( N = 45) had skin conductance and heart rate recorded continuously during a rest period, presentation of tones, and a simple reaction time test and were assessed for extraversion and behavioral impulsivity. The major aims were: (1) to generalize previous findings of smaller electrodermal responsivity to moderate stimuli and faster reaction time in extraverts, which had been reported for adult samples, to normal children; (2) to test the hypothesis that increasing arousal and stimulus significance by means of task performance would alter the negative correlation between extraversion and responsivity as had been shown in previous studies using different methods; and (3) to determine if extraversion and impulsivity interacted in their effects on these variables. Results showed that extraversion (independent of age and sex) was consistently negatively correlated with skin conductance response magnitudes to all stimuli—somewhat more strongly for reaction-time stimuli—and was negatively correlated with reaction time. This generalizes previous results to children and to significant stimuli. Behavioral impulsivity, which was independent of extraversion, was positively correlated with responsivity. The two variables together accounted for up to 33% of the variance of the responsivity measures. The results suggest that the positive relationship between extraversion and speed of reaction may be partially mediated by electrodermal responsivity. They are also consistent with a model of higher dopaminergic activity in extraverts.