Duplex perception refers to the
linguistic
Linguistics is the scientific study of human language. It is called a scientific study because it entails a comprehensive, systematic, objective, and precise analysis of all aspects of language, particularly its nature and structure. Linguis ...
phenomenon whereby "part of the
acoustic signal is used for both a
speech and a nonspeech percept." A listener is presented with two simultaneous,
dichotic stimuli. One ear receives an isolated third-
formant
In speech science and phonetics, a formant is the broad spectral maximum that results from an acoustic resonance of the human vocal tract. In acoustics, a formant is usually defined as a broad peak, or local maximum, in the spectrum. For harmoni ...
transition that sounds like a nonspeech chirp. At the same time the other ear receives a base
syllable. This base syllable consists of the first two
formants
In speech science and phonetics, a formant is the broad spectral maximum that results from an acoustic resonance of the human vocal tract. In acoustics, a formant is usually defined as a broad peak, or local maximum, in the spectrum. For harmoni ...
, complete with formant transitions, and the third formant without a transition. Normally, there would be peripheral
masking in such a
binaural listening task but this does not occur. Instead, the listener's percept is duplex, that is, the completed syllable is perceived and the nonspeech chirp is heard at the same time. This is interpreted as being due to the existence of a special speech module.
The phenomenon was discovered in 1974 by Timothy C. Rand at the
Haskins Laboratories
Haskins Laboratories, Inc. is an independent 501(c) non-profit corporation, founded in 1935 and located in New Haven, Connecticut, since 1970. Haskins has formal affiliation agreements with both Yale University and the University of Connecticut; ...
associated with
Yale University
Yale University is a Private university, private research university in New Haven, Connecticut. Established in 1701 as the Collegiate School, it is the List of Colonial Colleges, third-oldest institution of higher education in the United Sta ...
.
Duplex perception was argued as evidence for the existence of distinct systems for general
auditory perception and
speech perception. It is also notable that this same phenomenon can be obtained with slamming doors.
See also
*
McGurk effect
References
Psychoacoustics
Phonetics
Cognition
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