The influence of emotion regulation, level of shyness, and habituation on the neuroendocrine response of three-year-old children.

The current study investigated the temperamental dispositions of 53 three-year-old children (27 males, 26 females) and their behavioral and physiological responses to a stranger approach situation. Results indicated that elevations in cortisol were predicted by the child's level of shyness (with both shy and bold children showing elevations), better emotion regulation, and attendance at daycare which was believed to measure habituation to interactions with unknown adults in a playroom setting. In addition, the majority of children, both shy and bold, had cortisol levels that had begun to recover by fifteen minutes after the initial assessment. This suggests that the major concern for inhibited children is not weak regulation, but rather more frequent activation of the HPA system in response to novelty and a perceptual framework that expects fear.