Published online by Cambridge University Press: 28 November 2008
On the basis of prior research and a theoretical analysis of picture naming, we examined three correlates of child picture naming difficulty: age of name acquisition, picture-to-name uncertainty, and name generality (instance or category names). Study 1 demonstrated that late age of acquisition and high adult name uncertainty were associated with increased naming difficulty for both single instance and category items from the Expressive One-Word Picture Vocabulary Test (EOWPVT) (Gardner, 1979). Age of acquisition was a particularly strong predictor for instance items. Moreover, category pictures were more difficult to name than single instance pictures with names of comparable age of acquisition. In Study 2, analysis of incorrect responses to category pictures demonstrated that children made more instance errors than adults, but not more errors of other kinds. Study 2 also showed that a child uncertainty measure correlated more strongly with EOWPVT item difficulty than the adult measure of Study 1. The findings suggest that picture naming scores reflect both the availability of the names in lexical memory and their accessibility, which, in turn, partly depend on the amount of interference from competing responses. Some implications for the interpretation and remediation of picture naming deficits are suggested.