Date of Completion

Spring 5-2-2014

Thesis Advisor(s)

Emily B. Myers; Rachel M. Theodore

Honors Major

Speech, Language and Hearing Sciences


Cognition and Perception | Cognitive Neuroscience | Psycholinguistics and Neurolinguistics


Previous research has found that perceptual learning, or normalizing the idiosyncratic phonemes of speech, causes a shift in speech sound category boundaries. The present study examined if perceptual learning was limited to the boundary or if also caused a shift in internal category structure. Seventeen individuals participated in three behavioral tasks to explicate this question. In the Lexical Decision task, participants were trained in either /s/-biasing or /ʃ/- biasing context. In the Goodness Judgment task, participants rated a continuum of sounds on perceived /s/ goodness using a designated scale. Finally, in the Phoneme Identification task, participants listened to the same continuum previously heard but were asked to classify the token as /s/ or /ʃ/. Results suggest a shift in internal category structure, which is consistent with the view that top down processing results in a shift in the perception of within category variation. Future studies seek to further explicate this question by examining the perceptual learning mechanism in language-impaired populations.