Children’s individual interests are sustained across development and predict later vocabulary development

The current study examines how children’s interests in particular natural object categories emerge and sustain over time, and how these interests influence later vocabulary development. Children’s knowledge and interest in various object categories were indexed by parent estimates of children’s category-specific vocabulary size and interests, and children’s pupillary dilation responses. Data from sixty-seven children tested at eighteen and twenty-four months of age suggested that (i) parent estimates of children’s categorical interests at 18-months was sustained at 24-months; (ii & iii) children’s pupillary arousal to objects from these categories at 18-months was not associated with either their pupillary arousal or parent estimates of children’s interest in those categories at 24-months; and (iv) children’s category-specific vocabulary knowledge at 24-months was significantly associated with parent estimates of children’s interests at 18-months. Taken together, this study documents the longitudinal relationship between children’s interests, parents’ awareness of their children’s interests and later vocabulary development.