Sorting out language and level: examining the relation between productive vocabulary and category differentiation

Abstract

In two experiments we examined the relation between productive vocabulary and categorization at the basic and superordinate levels. Experiment 1 assessed categorization using a spontaneous object-manipulation task; Experiment 2 used a structured task employing 3 different levels of verbal support. In both experiments 24-month-old children participated in two sessions, with different levels of categorization tested at each session. Each child's productive vocabulary was assessed using either the Reznick & Goldsmith (1989) short parental report or the MacArthur Communicative Development Inventory. In both experiments, children performed equally well at the basic and superordinate levels, regardless of the task or level of verbal support. In Experiment 1 productive vocabulary was correlated with categorization at the basic level: children with larger productive vocabularies were more successful on basic-level tasks. The same relation between productive vocabulary and basic-level categorization was seen in the lowest verbal support condition of Experiment 2. There was no relation between vocabulary score and categorization at the superordinate level in either experiment. Possible implications of these findings are discussed.