Phonetic category activation drives dimension-based adaptive tuning in speech perception

AbstractMultiple acoustic dimensions contribute to speech categorization. Yet highly diagnostic dimensions contribute greater ‘perceptual weight’ in influencing speech categorization than less diagnostic dimensions. Recent research demonstrates that perturbations in short-term input regularities lead to rapid dynamic re-weighting of auditory dimensions. Here, we test the hypothesis that phonetic-category-level activation via a highly diagnostic acoustic dimension is critical in driving this rapid tuning of how input maps to phonetic categories. To do so, we manipulate the inherent relative effectiveness, the perceptual weight, of two acoustic dimensions in signaling English vowel categorization using noise-vocoded versus clear speech. We observe that rapid tuning across statistical regularities is affected by dimensions’ effectiveness in signaling the vowel categories. These findings indicate that category activation via a highly diagnostic dimension drives adaptive tuning in speech perception, consistent with error-driven supervised learning.

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