Dysregulated Fear, Social Inhibition, and Respiratory Sinus Arrhythmia: A Replication and Extension.

Behavioral inhibition indicates increased risk for development of social anxiety. Recent work has identified a pattern of dysregulated fear (DF), characterized by high fear in low-threat situations, that provides a more precise marker of developmental risk through early childhood. This study tested a new longitudinal sample of children (n = 124) from ages 24 to 48 months. Replicating prior findings, at 24 months, we identified a pattern of fearful behavior across contexts marked by higher fear to putatively low-threat situations. DF was associated with higher parental report of social inhibition at 24, 36, and 48 months. Extending prior findings, we observed differences in cardiac physiology during fear-eliciting situations, suggesting that the neurobiological underpinnings of DF relate to difficulty with regulation.