The influence of neighborhood density and phonotactic probability on representational and production factors in word learning

Lori Heisler, Purdue University

Abstract

Studies from adult word recognition (Luce & Pisoni, 1998; Vitevitch & Luce, 1998) provide evidence for two levels of representation in speech processing; lexical and sublexical. These studies have shown that phonotactic frequency influences processing of non-words at the sublexical level while neighborhood density influences processing of words at the lexical level. The purpose of the present study was to examine the influence of statistical factors (i.e., phonotactic frequency and neighborhood density) on phonological and motor representations in speech production in both words and nonwords. A word learning paradigm was used to teach children and adults novel words that varied in phonotactic frequency and neighborhood density. Data were examined when phonetic forms were non-words (i.e., when no object referent was attached) and when phonetic forms were words (i.e., when a referent was attached through fast mapping). Two methods of analysis were included: (1) kinematic variability of speech movement patterning; and (2) measures of segmental accuracy. Results showed that phonotactic frequency influenced the stability of movement patterning whereas neighborhood density influenced phonetic accuracy. Both factors (phonotactic frequency and neighborhood density) showed effects in both words and non-words. Finally, children generally demonstrated more overall learning effects than adults, as indicated by decreases in movement variability with increased motor practice. The present results support that there are at least two levels of representation; however, the factors that influence each level are more complex than previously regarded. The statistical tendencies appear to be so sensitive during assessment that methodologies used across disparate studies need to be carefully considered when the results are reconciled into a single model. The present results support the use of a two-representational model for both children and adults, but findings suggest that experiential factors (e.g., resource allocation or practice) may influence the behavioral output that the model will predict for each group.

Degree

Ph.D.

Advisors

Goffman, Purdue University.

Subject Area

Developmental psychology|Speech therapy

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