Although traditional psychophysical accounts emphasize categorical boundaries in voice onset time, recent perceptual studies demonstrate that voicing and speech categorization can be processed and perceived as a gradient scale.
The claim posits that voicing is perceived and produced as a gradient scale rather than a strict binary distinction. While classical literature (e.g., paper [0]) supports categorical perception (sharp boundaries), modern psycholinguistic research using continuous rating scales and subcategorical measures (papers [1], [10], [11]) reveals significant gradiency and individual differences in how voicing and phonetic contrasts are perceived. Thus, the current weight of evidence supports the notion of gradient speech perception alongside categorical effects.