Is Consonant Perception Linked to Within-Category Dispersion or Across-Category Distance?

This study investigated the relation between the internal structure of phonetic categories and consonant intelligibility. For two phonetic contrasts (/s/-/ʃ/ and /b/-/p/), 32 iterations per category were elicited for each of 40 talkers from a same accent group and age range, and measures of cross-category distance and within-category dispersion were obtained. These measures varied substantially across talkers but were not correlated across both contrasts suggesting that degree of cross-category distance or within-category dispersion is not consistent within-speaker. For each contrast, consonant identification tests in mild babble noise, that presented the complete set of iterations for eight talkers showing extreme values in these two measures, revealed some talker effects on reaction time. However, these did not appear to be correlated with either cross-category distance or within-category dispersion for those talkers.