Characterizing changes in parent labeling and gesturing and their relation to early communicative development

A B S T R A C T In a longitudinal study, 17 parent-child dyads were observed during free-play when the children were 1 ; 0, 1; 6, and 2;0. Parents' labelling input in the verbal and gestural modalities was coded at each session, and parents completed a vocabulary checklist for their children at each visit. We analysed how the frequency of labelling in the verbal and gestural modalities changed across observation points and how changes in parental input related to children's vocabulary development. As a group, parents' verbal labelling remained constant across sessions, but gestural labelling declined at 2 ; 0. However, there are notable individual differences in parental trajectories in both modalities. Parents whose verbal labelling frequency increased over time had children whose vocabulary grew more slowly than those whose labelling frequency decreased, remained constant, or peaked at 1;6. There were few systematic relations between patterns of parental gesturing and children's vocabulary development. Parents' verbal and gestural labelling patterns also appeared dissociable. However, parents' words and gestures were correlated when their children were 1 ;6, suggesting that [*] We thank Mike Tomasello and Susan Goldin-Meadow for helpful insights. We also thank the parents and children who participated in this study for their dedication to this project. Finally, we thank Rebecca Fiscal and Rachel Robertson for their support and assistance

Comparison and Function in Children’s Object Categorization

Although young children often rely on salient perceptual cues, such as shape, when categorizing novel objects, children shift towards deeper relational reasoning when they compare category members or attend to functional properties. In this study, we investigated the independent and combined effects of comparison and function in children’s categorization of novel objects. Across two experiments, we found that comparing two perceptually similar category members led children to discover non-obvious relational features that supported their categorization of novel objects. Together, these findings underscore the difficulty in categorizing novel objects but demonstrate that comparison may aid in this process by rendering less obvious relational structures more salient, thus inducing a shift towards a categorical rather than perceptual response