Infants' responses to frustrating situations: continuity and change in reactivity and regulation.

We examined continuity, stability, and change in behaviors reflecting infant reactivity and regulation. Healthy infants were observed in laboratory situations designed to elicit frustration when they were 5 (N = 87) and 10 months of age (N = 82). Behaviors indicative of reactivity included objective ratings of average intensity cry, peak intensity cry, and latency to cry. In addition, durations of orienting, avoidant, and nonnegative communicative behaviors were assessed as measures of regulation at each age. Results showed that several behaviors changed in level over time. In addition, Confirmatory Factor Analysis revealed both structural continuity and discontinuity: Behaviors were organized into 2 similar factors at 5 and 10 months (Reactivity and Regulation), but the relation between reactivity and regulation became increasingly independent over time, such that reactivity and regulation were negatively correlated at 5 months but not at 10 months. Finally, model-fitting revealed cross-dimension but not within-dimension stability (5-month reactivity predicted 10-month regulation).