Haskins Publications

Number	731
Year	1990
Drawer	13
Entry Date	11/15/1999
Authors	Repp, B. H., & Crowder, R. G.
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Publication	Journal of the Acoustical Society of America, 88, 2080-2090.
url	http://www.haskins.yale.edu/Reprints/HL0731.pdf
Abstract	In same-different discrimination tasks employing isolated vowel sounds, Ss often give significantly more "different" responses to one order to two stimuli than to the other order. A neutralization hypothesis has been proposed to account for this, such that the first vowel of the pair changes in quality in memory toward that of the neutral vowel schwa. Three experiments were conducted to evaluate this hypothesis. Experiment 1 used nine groups of stimuli from varying points in the vowel space of American English, arranged in a way that allowed clear predictions about the magnitude & direction of possible order effects (N = 24 undergraduates). In experiment 2, four vowel sets that yielded results supporting the neutralization hypothesis in experiment 1 were used as stimuli (N = 18). Experiment 3 used two vowel continua (N = 24). Overall results supported the hypothesis with a large stimulus set but were conflicting for smaller stimulus sets. Rather than becoming more similar to schwa, the first vowel seems to drift toward the interior of the stimulus range employed in a given test. Possible explanations for this finding are considered.
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