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

Behavioral inhibition is a temperament assessed in the toddler period via children's responses to novel contexts, objects, and unfamiliar adults. Social reticence is observed as onlooking, unoccupied behavior in the presence of unfamiliar peers and is linked to earlier behavioral inhibition. In the current study, we assessed behavioral inhibition in a sample of 262 children at ages 2 and 3, and then assessed social reticence in these same children as they interacted with an unfamiliar, same-age, same-sex peer at 2, 3, 4, and 5 years of age. As expected, early behavioral inhibition was related to social reticence at each age. However, multiple trajectories of social reticence were observed including High-Stable, High-Decreasing, and Low-Increasing, with the High-Stable and High-Decreasing trajectories associated with greater behavioral inhibition compared to the Low-Increasing trajectory. In addition, children in the High-Stable social reticence trajectory were rated higher than all others on 60-month Internalizing problems. Children in the Low-Increasing trajectory were rated higher on 60-month Externalizing problems than children in the High-Decreasing trajectory. These results illustrate the multiple developmental pathways for behaviorally inhibited toddlers and suggest patterns across early childhood associated with heightened risk for psychopathology.