Fearful Temperament and Stress Reactivity Among Preschool-Aged Children.

In this study, we examined the relation between physiological stress-reactivity and temperamental fearfulness in 162 preschool-aged children. Both the autonomic and neuroendocrine arms of the mammalian stress system were examined. Larger stress responses were defined as greater sympathetic activation, parasympathetic withdrawal and cortisol increases to stressor tasks. Fearful temperament was examined using parent report and behavior in response to fear-evocative laboratory tasks. There was little evidence that larger sympathetic activation or parasympathetic withdrawal was associated with fearful temperament. Greater cortisol reactivity, however, was associated with fearful temperament. Additional analyses examined those children who were consistently fearful across all measures, and the results remained largely the same. However, there was some suggestion that consistently fearful compared to non-fearful children might be more likely to exhibit sympathetic activation to the fear-evocative stimuli. These findings provide support for the argument that fearful temperament is associated with greater stress reactivity in young children. Nonetheless the size of the associations was small and future studies will need to determine whether reactivity of stress-sensitive physiological systems contributes to the development of individual differences in fearful temperament or merely reflects these differences.