Notes that 4-month olds who show a low threshold to become distressed and motorically aroused to unfamiliar stimuli are more likely than others to become fearful and subdued during early childhood, while infants who show a high arousal threshold are more likely to become bold and sociable. Considers implications for psychopathology and relation…

Evaluated brainstem auditory evoked responses (BAERs) on 10- to 12-year-olds who had been classified as high or low reactive to unfamiliar stimuli at 4 months of age. Found that children previously classified as high reactive at 4 months had larger wave V components than did low reactive children, possibly suggesting greater excitability in…