Individual differences in response to Stress and Cerebral Asymmetry

A number of studies suggest that the pattern of resting brain electrical activity, particularly in the frontal region, is a marker for individual differences in certain aspects of temperament or personality. We performed two studies with infants in which we observed their responses to brief maternal separation and recorded the electroencephalogram (EEG) either at the same session as separation or some weeks later. Study 1 examined the separation responses of 33 infants at 14 and 24 months of age. Study 2 investigated separation distress in 13 infants seen longitudinally, from 7 to 12 months of age. Across both studies, infants exhibiting right frontal activation were more likely to cry to maternal separation. The findings suggest that there is modest stability of frontal asymmetry during the second half of the first year of life. Differences between male and female infants in response to separation and frontal asymmetry were also found.