Poster #66 - A Within-Individual Investigation of the Association Between Children’s Vocabulary Skills and Externalizing Problems

• In Event: 1-115 - Poster Session 03
  In Poster Session: PS 03 Section - Developmental Psychopathology

Integrative Statement

Considerable research has established that poor language skills are concurrently associated with externalizing problems. Some work has shown that language skills prospectively predict later externalizing problems. However, prior work has not determined whether language skills play a causal role in the development of externalizing problems because the association in prior studies could reflect a third variable. Examining the association within the individual uses the individual as their own control, removes all between-subject confounds, and provides a stronger test of developmental process. Prior work has not examined whether within-individual changes in language skills predict within-individual changes in externalizing problems. Moreover, few studies have examined possible mechanisms that explain the effect of language skills on the development of externalizing problems.

The present study considered children’s vocabulary, an important aspect of language skills, and examined whether within-child changes in vocabulary skills predict within-child changes in externalizing problems. The study also examined whether social skills might be a mechanism explaining the association between vocabulary and externalizing problems.

Participants included children (N=1,364) followed longitudinally from ages 6 to 10 years in the NICHD Study of Early Child Care and Youth Development. Vocabulary skills were assessed using the Picture Vocabulary subtest of the Woodcock-Johnson Psychoeducational Battery-Revised. Externalizing problems were rated by mothers on the Child Behavior Checklist and by teachers on the Teacher’s Report Form. Social skills were rated by teachers on the Social Skills Rating Scale.

We fit growth curve models using mixed effects modeling. We centered vocabulary skills around the child’s own mean (person-mean centering) to disaggregate within- and between-individual effects.

Model results are in Table 1. Children’s means of vocabulary skills did not predict their intercepts or slopes of externalizing problems. However, within-individual changes in vocabulary skills predicted later within-individual changes in parent-reported and, at a trend-level, teacher-reported externalizing problems. Children who showed greater improvements in vocabulary showed greater decreases in externalizing problems. The association held controlling for the child’s sex, socioeconomic status, and nonverbal intelligence.

By contrast, reading and math skills did not predict externalizing problems, suggesting that vocabulary in particular may play a unique role. Vocabulary skills did not predict internalizing problems or ADHD symptoms, however, suggesting that they may have more specific effects on externalizing problems. The reverse direction of association was not observed; externalizing problems did not predict changes in vocabulary, suggesting that the direction of effect is more likely from vocabulary skills to later externalizing problems than the reverse.

Social skills did not account for the association of vocabulary skills with mother-rated externalizing problems, but partially accounted for the association with teacher-rated externalizing problems (see Table 2).

Findings suggest that (a) vocabulary skills play may a unique role in the development of externalizing problems, (b) the direction of effect is more likely from vocabulary skills to later externalizing problems than the reverse, and (c) part of the effect of vocabulary skills on later externalizing problems may be explained by children’s social skills. Vocabulary and social skills may be an important target for preventing the development of externalizing problems.

Authors

• Isaac Petersen, University of Iowa, Department of Psychological and Brain Sciences
  Presenting Author

• Brandon LeBeau, University of Iowa
  Non-Presenting Author