Latent class trajectories of infant temperament and associations with problem behavior at two years of age

Individual differences in temperament have been well-described, but individual differences in temperament trajectories require elaboration. Specifically, it is unknown if subgroups of infants display different developmental patterns and if these patterns relate to later behavioral problems. The aims were to identify distinct developmental patterns in broad dimensions of temperament among typically developing infants, to determine whether these developmental patterns differ by sex, to evaluate how developmental patterns within each dimension of temperament relate to developmental patterns within other dimensions of temperament, and to determine whether developmental patterns of infant temperament are associated with internalizing and externalizing behavior at 2 years of age. Data from the longitudinal Alberta Pregnancy Outcomes and Nutrition study (n = 1,819) were used to model latent class trajectories of parent-reported infant temperament at 3, 6, and 12 months. Four to five unique latent trajectories were identified within each temperament dimension. Sex was not associated with trajectory groups. Developmental coordination was observed between trajectories of negative emotionality and regulatory capacity, and between regulatory capacity and positive affect, but not between positive affect and negative emotionality. Negative emotionality and regulatory capacity predicted internalizing and externalizing behavior. Patterns of development in infant temperament, and not just intensity of temperament, contribute toward later problem behavior.