Temperamental contributions to social behavior: the moderating roles of frontal EEG asymmetry and gender.

OBJECTIVES Infant temperament is thought to provide one of the fundamental bases for social and emotional development. Few studies have examined the direct and indirect influences of early temperament and physiological disposition on later development. METHOD This article presents results of a longitudinal study that took place between the years 1989 and 1996 in which the relations between maternal reports of negative reactivity at 9 months of age and maternal ratings and laboratory observations of social wariness and sociability at 4 years of age (n = 97) were examined. Also examined were the moderating roles of (1) frontal electroencephalogram (EEG) asymmetry as assessed at 9 months of age and (2) the child's gender. RESULTS Negative reactivity predicted social wariness for infants with right frontal EEG asymmetry, but not for those with left frontal EEG asymmetry and for boys but not girls. The only significant predictor of sociability was gender. Specifically, at 4 years of age girls were rated higher on the measure of sociability than were boys. CONCLUSION The findings are discussed in terms of the roles of frontal EEG asymmetry and gender in moderating the impact of temperamental negative reactivity on later social behavior.