Hand preference trajectories as predictors of language outcomes above and beyond SES: Infant patterns explain more variance than toddler patterns at 5 years of age.

Prior studies found hand preference trajectories predict preschool language outcomes. However, this approach has been limited to examining bimanual manipulation in toddlers. It is not known whether hand preference during infancy for acquiring objects (i.e., reach-to-grasp) similarly predicts childhood language ability. The current study explored this motor-language developmental cascade in 90 children. Hand preference for acquiring objects was assessed monthly from 6 to 14 months and language skill was assessed at 5 years. Latent class growth analysis identified three infant hand preference classes: left, early right, and late right. Infant hand preference classes predicted 5-year language skills. Children in the left and early right classes, who were categorized as having a consistent hand preference, had higher expressive and receptive language scores relative to children in the inconsistent late right class. Consistent classes did not differ from each other on language outcomes. Infant hand preference patterns explained more variance for expressive and receptive language relative to previously reported toddler hand preference patterns, above and beyond socioeconomic status (SES). Results suggest that hand preference, measured at different time points across development using a trajectory approach, is reliably linked to later language.

Interactions among stress, behavioral inhibition, and delta-beta coupling predict adolescent anxiety during the COVID-19 pandemic.

The COVID-19 pandemic brought about unprecedented changes and uncertainty to the daily lives of youth. The range of adjustment in light of a near-universal experience of COVID restrictions highlights the importance of identifying factors that may render some individuals more susceptible to heightened levels of anxiety during stressful life events than others. Two risk factors to consider are temperamental behavioral inhibition (BI) and difficulties in emotion regulation (ER). As such, the current paper focused on BI examined prior to COVID, because of its developmental link to anxiety and ER, as difficulties may be associated with differences in anxiety. We examined a neurocognitive marker of ER processes, delta-beta coupling (DBC). The current paper had two goals: (1) to examine BI in relation to COVID-related worry and social anxiety experienced during the pandemic, and (2) to explore the role of individual differences in early DBC in the relationship between BI and anxiety outcomes 6 months apart during COVID-19 (n = 86; T1 Mage  = 15.95, SD = 1.73; T6 Mage  = 16.43, SD = 1.73). We found support for the moderating role of DBC in the relationship between BI levels and social anxiety disorder (SAD) symptom severity during the pandemic. Here, high BI was predictive of increased SAD symptom levels in adolescents with stronger DBC.