Phonetic trading relations and context effects: new experimental evidence for a speech mode of perception.

This article reviews a variety of experimental findings, most of them obtained in the last few years, that show that the perception of phonetic distinctions relies on a multiplicity of acoustic cues and is sensi tive to the surrounding context in very specific ways. Nearly all of these effects have correspondences in speech production, and they are readily explained by the assumption that listeners make continuous use of their tacit knowledge of speech patterns. A general auditory theory that does not make reference to the specific origin and function of speech can, at best, handle only a small portion of the wealth of phenomena reviewed here. Special emphasis is placed on several recent studies that obtained different patterns of results depending on whether identical stimuli were perceived as speech or as nonspeech. These findings provide strong empirical evidence for the existence of a special speech mode of perception.