Linguistic and cognitive abilities in infancy: when does language become a tool for categorization?

Infants' ability to form new object categories based on either visual or naming information alone was evaluated at two different ages (16 and 20 months) using an object manipulation task. Estimates of productive vocabulary size were also collected. Infants at both ages showed evidence of using visual information to categorize the objects, while only the older ones used naming information. Moreover, there was a correlation between vocabulary size and name-based categorization among the 20-month-olds. The present results establish that infants as young as 20 months can use the non-obvious cue of naming to categorize objects. The possibility of a link between this ability and lexical development is discussed.