Fast Mapping 1 Running head: FAST MAPPING SKILLS IN THE DEVELOPING LEXICON Fast Mapping Skills in the Developing Lexicon

Purpose: This preliminary investigation is a longitudinal study of fast mapping skills in normally developing children, 16 to 18 months of age. The purpose was to examine the effects of practice on the accessibility of words in lexical memory. Method: Eight children were taught the names of 24 unfamiliar objects over 12 weekly training sessions. The amount of practice children had with individual words varied as a function of session. Data were compared to a control group of children, matched on productive vocabulary, who were exposed to the same experimental words at the first and last sessions only. Results: The results showed that for children in the experimental group, extended practice with a novel set of high practice words led to the rapid acquisition of a second set of low practice words. Children in the control group did not show the same lexical advantage. Conclusions: The data suggest that learning some words primes the system to learn more words. Vocabulary development can thus be conceptualized as a continual process of fine-tuning the lexical system to enable increased accessibility to information. Implications for the treatment of children with word finding difficulties are considered.