Children's overextensions (e.g. referring to a pomegranate
as apple)
raise intriguing questions regarding early word meanings. Specifically,
how do object shape, taxonomic relatedness, and prior lexical knowledge
influence children's overextensions? The present study sheds new light
on this issue by presenting items that disentangle the three factors of
shape, taxonomic category, and prior lexical knowledge, and by using a
novel comprehension task (the screened-alternative task) in which
children can indicate negative exemplars (e.g. which items are notapples). 49 subjects in three age groups participated
(Ms=2;0, 2;6, and 4;5). Findings indicate: (1) Error patterns
differed by task. In
production, errors were overwhelmingly due to selecting items that
matched the target word in both shape and taxonomic relatedness.
In
comprehension, more errors were based on either shape alone or
taxonomic relatedness alone, and the nature and frequency of the
overextensions interacted with prior lexical knowledge. (2) Error
patterns also differed markedly based on the word being tested (apple
vs. dog), in both comprehension and production. (3) As predicted,
errors were more frequent in production than comprehension, though
only for children in the two younger age groups. Altogether, the study
indicates that overextensions are not simply production errors, and that
both taxonomic relatedness and object shape play a powerful role in
early naming errors.