Continuity and Discontinuity of Behavioral Inhibition and Exuberance: Psychophysiological and Behavioral Influences across the First Four Years of Life

TLDR

The study screened 433 four‑month‑old infants for temperament traits linked to behavioral inhibition, then followed 153 selected infants longitudinally up to age four, measuring behavioral inhibition and frontal EEG asymmetry at multiple time points. Four‑month temperament modestly predicted inhibition through age two and reticence at age four; continuously inhibited infants showed right frontal EEG asymmetry from nine months onward, whereas those who shifted to non‑inhibited did not, and changes in inhibition correlated with nonparental care, while exuberant infants displayed high behavioral continuity.

Abstract

Four-month-old infants were screened (N = 433) for temperamental patterns thought to predict behavioral inhibition, including motor reactivity and the expression of negative affect. Those selected (N = 153) were assessed at multiple age points across the first 4 years of life for behavioral signs of inhibition as well as psychophysiological markers of frontal electroencephalogram (EEG) asymmetry. Four-month temperament was modestly predictive of behavioral inhibition over the first 2 years of life and of behavioral reticence at age 4. Those infants who remained continuously inhibited displayed right frontal EEG asymmetry as early as 9 months of age while those who changed from inhibited to noninhibited did not. Change in behavioral inhibition was related to experience of nonparental care. A second group of infants, selected at 4 months of age for patterns of behavior thought to predict temperamental exuberance, displayed a high degree of continuity over time in these behaviors.