The Myth of Categorical Perception

Categorical perception is likely the single finding from speech perception with the biggest impact on cognitive science. However, within speech perception, it is widely known to be an artifact of task demands. Categorical perception is empirically defined as a relationship between phoneme identification and discrimination. As discrimination tasks do not appear to require categorization, this was thought to support the claim that listeners perceive speech solely in terms of linguistic categories. However, 50 years of work using discrimination tasks, priming, the Visual World Paradigm, and Event Related Potentials has roundly rejected this account. This paper reviews the origins and impact of this scientific meme and the work challenging it. It discusses work showing that the encoding of auditory input is continuous, not categorical, and describes the modern theoretical synthesis in which listeners preserve fine-grained detail to enable more flexible processing. This synthesis is fundamentally inconsistent with categorical perception. This leads to a new understanding of how to use and interpret the most basic paradigms in speech perception – phoneme identification along a continuum and has implications for understanding language and hearing disorders, development, and multilingualism. This challenges the field to develop new ways to describe and measure speech categorization.