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
Abstract
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.