Frontal activation asymmetry and social competence at four years of age.

The pattern of frontal activation as measured by the ongoing electroencephalogram (EEG) may be a marker for individual differences in infant and adult disposition to respond with either positive or negative affect. We studied 48 4-year-old children who were first observed in same-sex quartets during free-play sessions, while making speeches, and during a ticket-sorting task. Social and interactive behaviors were coded from these sessions. Each child was subsequently seen 2 weeks later when EEG was recorded while the child attended to a visual stimulus. The pattern of EEG activation computed from the session was significantly related to the child's behavior in the quartet session. Children who displayed social competence (high degree of social initiations and positive affect) exhibited greater relative left frontal activation, while children who displayed social withdrawal (isolated, onlooking, and unoccupied behavior) during the play session exhibited greater relative right frontal activation. Differences among children in frontal asymmetry were a function of power in the left frontal region. These EEG/behavior findings suggest that resting frontal asymmetry may be a marker for certain temperamental dispositions.