The Physiology and Psychology of Behavioral Inhibition in Children

Abstract

Longitudinal study of 2 cohorts of children selected in the second or third year of life to be extremely cautious and shy (inhibited) or fearless and outgoing (uninhibited) to unfamiliar events revealed preservation of these 2 behavioral qualities through the sixth year of life. Additionally, more of the inhibited children showed signs of activation in 1 or more of the physiological circuits that usually respond to novelty and challenge, namely, the hypothalamic-pituitary-adrenal axis, the reticular activating system, and the sympathetic arm of the autonomic nervous system. It is suggested that the threshold of responsivity in limbic and hypothalamic structures to unfamiliarity and challenge is tonically lower for inhibited than for uninhibited children.

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“…Working memory has been linked to the frontal lobes, with verbal ability predominantly on the left side in most individuals. Studies linking approach behavior in anxious individuals to left anterior activation on EEG [51], reduced left anterior activation in behaviorally inhibited children [52], successful treatment of anxiety using verbally mediated cognitive behavioral strategies [5], and deficits in frontal lobe functions in ADHD [53] are all consistent with this idea. The lack of sensitivity to threat (angry voice) we found in ANX + ADHD (in contrast to 'pure' ANX) is also consistent with this model.…”

Longitudinal trajectories of social reticence with unfamiliar peers across early childhood.

“…At 24 and 36 months, behavior and affect were observed in the laboratory during a standard behavioral inhibition paradigm (e.g., Fox et al, 2001; Kagan, Reznick, & Snidman, 1987). In addition, at 24, 36, 48, and 60 months, each child was observed in the laboratory interacting with an unfamiliar, same-age, same-sex peer, recruited from the community without consideration of their temperamental reactivity.…”

“…At both 24 and 36 months of age, a laboratory visit was conducted, during which mothers and their children participated in a paradigm designed to assess behavioral inhibition (e.g., Fox et al, 2001; Kagan et al, 1987). Stranger, Robot, and Tunnel tasks were used to characterize behavioral inhibition for this study (e.g., White, McDermott, Degnan, Henderson, & Fox, 2011, for details).…”

Maternal emotional availability at bedtime and infant cortisol at 1 and 3months

“…Hyperarousal of the HPA axis, such that an individual shows elevated cortisol levels across the day, has been associated with internalizing behavior in both early and middle childhood (14–16). Hypoarousal of the HPA axis, such that an individual shows reduced cortisol secretion across the day, is generally associated with externalizing behavior (17-18).…”