Inhibited and Uninhibited Children: A Follow-Up Study

REZNICK, J. STEVEN; KAGAN, JEROME; SNIDMAN, NANCY; GERSTEN, MICHELLE; BAAK, KATHERINE; and ROSENBERG, ALLISON. Inhibited and Uninhibited Children: A Follow-up Study. CHILD DEVELOPMENT, 1986, 57, 660-680. A group of 46 children classified at 21 months as either behaviorally inhibited or uninhibited, and 18 children who were classified as falling at neither extreme, were observed at 5 /2years of age in contexts designed to evaluate behavior in social situations and heart rate, heart rate variability, and pupillary dilation to cognitive tasks. Additionally, 43 of the 46 inhibited or uninhibited children had been evaluated in similar contexts when they were 4 years of age. At age 51/, the formerly inhibited children, compared with the uninhibited ones, were more inhibited with peers in both laboratory and school, as well as with an adult examiner in a testing situation, and more cautious in a situation of mild risk. As at the earlier ages, more inhibited children had a relatively high and stable heart rate. The inhibited children also had tonically larger pupillary dilations to cognitive stress, were either impulsive or reflective on a test with response uncertainty, and their mothers described them as shy with unfamiliar peers. It was suggested that one or more of the stress circuits that link the hypothalamus to the pituitary, reticular activating system, and sympathetic chain are at a higher level of excitability among inhibited than among uninhibited children.