Individual Differences in Speech Categorization and Perceptual Cue Reliance Across Phonological Contrasts

Individual listeners differ in how they utilize acoustic cues when categorizing speech sounds, but the relationship between cue weighting and specific dimensions of speech categorization remains unclear. It is also understudied whether individual differences in categorization are stable across phonological contrasts. This study determines which and to what extent differences in speech categorization indices (categorization gradiency and consistency) are associated with differences in cue reliance. Another goal is to examine the stability of the categorization indices by comparing categorization patterns across two distinct speech continua: lexical stress contrast and stop voicing contrast. English-speaking adults (n=61) completed two-alternative forced-choice tasks across the contrasts, estimating a speech token on a discrete scale, and visual analog scaling tasks across the contrasts, rating a speech token on a continuous scale. Across the contrasts, differences in categorization consistency—the stability of a listener’s percept across multiple encounters with speech sounds—are closely linked to individuals’ overall reliance on cues for a given contrast. Cross-contrast comparisons revealed that categorization consistency in one contrast predicted consistency in the other, whereas gradiency did not. These suggest that categorization consistency is a stable, trait-like property that is closely linked to how listeners use relevant acoustic cues comprehensively.