Using data from an eight-year longitudinal study of 214 children's social and emotional development, I conducted three studies to (1) examine patterns of agreement for internalizing (INT) and externalizing (EXT) symptomatology among different informants (mothers, fathers, teachers, and adolescents) using a recently developed structural equation modeling approach for multi-trait, multi-method data; (2) examine the developmental trajectories for INT and EXT and predict individual differences in symptom development using temperament and parenting variables; and (3) describe patterns of INT and EXT co-occurrence and predict these patterns from temperament and parenting. In Study 1, longitudinal invariance was established for mothers', fathers' and teachers' reports over a six-year period. Sex, age, and SES did not substantially moderate agreement among informants, although both sex and age were differentially related to symptomatology depending on the informant. Agreement among teachers and mothers, but not among mothers and fathers, differed by domain of symptomatology, and was greater for EXT than for INT. In Study 2, latent profile analysis, a person-centered analytic approach, did not provide easily interpretable patterns of symptom development, a failure that is likely the result of the relatively modest sample size. Latent growth curve models, an alternative analytic approach, did provide good fit to the data. Temperament and parenting variables were examined as predictors of the latent growth parameters in these models. Although there was little prediction of the slope, effortful control was negatively related to overall levels of EXT, whereas impulsivity and anger were positively related. Mutually responsive orientation, a measure of the parent-child relationship, was a more consistent predictor of EXT than was parental warmth. Furthermore, the relation between mutually responsive orientation and EXT was partially mediated by inhibitory control. Across informants, there were few consistent predictors of INT. In Study 3, latent profile analysis was used to classify individuals into different patterns of INT and EXT co-occurrence. In these models, a similar class structure was identified for mothers and for teachers. When temperament and parenting were examined as predictors of co-occurring symptomatology, few significant interactions were found and results largely replicated prior findings from this data set using arbitrary symptom groups.

This study examines the relations among three aspects of temperament (shyness, impulsivity, and effortful control), resting respiratory sinus arrhythmia (RSA) recorded during a calming film and RSA suppression during three behavioral measures of effortful control, and adjustment (anxiety and externalizing behavior) in a sample of 101 preschool-age children. Principal components analysis was used to create composites for effortful control, shyness, impulsivity, anxiety, and externalizing behavior, and hierarchical regression analysis was used to test the study hypotheses. As expected, baseline RSA was negatively related to effortful control in shy children, but was unrelated to effortful control in children who were not shy. It was hypothesized that high baseline RSA would reduce the relation between shyness and anxiety, and between impulsivity and externalizing behavior; this hypothesis was supported for externalizing behavior, but not for anxiety. The interaction between impulsivity and RSA as a predictor of externalizing was statistically independent of effortful control, indicating that these are unique effects. Finally, it was hypothesized that RSA suppression would be positively related to effortful control for children low, but not high, in shyness. There was a marginal interaction between shyness and RSA suppression, with RSA suppression marginally negatively related to EC for children low in shyness, but unrelated to effortful control for children high in shyness; the direction of this association was opposite predictions. These findings indicate that RSA is more strongly related to effortful control for children high in shyness, and that it consequently may not be appropriate to use RSA as an index of EC for all children. This study also draws attention to the need to consider the context in which baseline RSA is measured because a true baseline may not be obtained for shy children if RSA is measured in an unfamiliar laboratory context. The finding that high RSA moderated (but did not eliminate) the relation between impulsivity and externalizing behavior is consistent with the conceptualization of RSA as a measure of self-regulation, but further research is needed to clarify the mechanism underlying this effect.