Investigating the developmental timing of self-regulation in early childhood.

Self-regulation often refers to the executive influence of cognitive resources to alter prepotent responses. The ability to engage cognitive resources as a form of executive process emerges and improves in the preschool-age years while the dominance of prepotent responses, such as emotional reactions, begins to decline from toddlerhood onward. However, little direct empirical evidence addresses the timing of an age-related increase in executive processes and a decrease in age-related prepotent responses over the course of early childhood. To address this gap, we examined children's individual trajectories of change in prepotent responses and executive processes over time. At four age points (24 months, 36 months, 48 months, and 5 years), we observed children (46% female) during a procedure in which mothers were busy with work and told their children they had to wait to open a gift. Prepotent responses included children's interest in and desire for the gift and their anger about the wait. Executive processes included children's use of focused distraction, which is the strategy considered optimal for self-regulation in a waiting task. We examined individual differences in the timing of age-related changes in the proportion of time spent expressing a prepotent response and engaging executive processes using a series of nonlinear (generalized logistic) growth models. As hypothesized, the average proportion of time children expressed prepotent responses decreased with age, and the average proportion of time engaged in executive processes increased with age. Individual differences in the developmental timing of changes in prepotent responses and executive process were correlated