Duplex perception
Encyclopedia
Duplex perception refers to the linguistic
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
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, 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
associated with Yale University
.
Duplex perception was argued as evidence for the existence of distinct systems for general auditory perception
and speech perception
. However, the same phenomenon can be obtained with slamming doors.
Natural language
In the philosophy of language, a natural language is any language which arises in an unpremeditated fashion as the result of the innate facility for language possessed by the human intellect. A natural language is typically used for communication, and may be spoken, signed, or written...
phenomenon whereby "part of the acoustic signal
Sound
Sound is a mechanical wave that is an oscillation of pressure transmitted through a solid, liquid, or gas, composed of frequencies within the range of hearing and of a level sufficiently strong to be heard, or the sensation stimulated in organs of hearing by such vibrations.-Propagation of...
is used for both a speech and a nonspeech percept." A listener is presented with two simultaneous, dichotic stimuli
Dichotic listening
In cognitive psychology, dichotic listening is a procedure commonly used to investigate selective attention in the auditory system. In dichotic listening, two different auditory stimuli are presented to the participant simultaneously, one to each ear, normally using a set of headphones...
. One ear receives an isolated third-formant
Formant
Formants are defined by Gunnar Fant as 'the spectral peaks of the sound spectrum |P|' of the voice. In speech science and phonetics, formant is also used to mean an acoustic resonance of the human vocal tract...
transition that sounds like a nonspeech chirp. At the same time the other ear receives a base syllable
Syllable
A syllable is a unit of organization for a sequence of speech sounds. For example, the word water is composed of two syllables: wa and ter. A syllable is typically made up of a syllable nucleus with optional initial and final margins .Syllables are often considered the phonological "building...
. This base syllable consists of the first two formants, complete with formant transitions, and the third formant without a transition. Normally, there would be peripheral masking
Auditory masking
Auditory masking occurs when the perception of one sound is affected by the presence of another sound.- Simultaneous masking :Simultaneous masking is when a sound is made inaudible by a "masker", a noise or unwanted sound of the same duration as the original sound.-Critical bandwidth:If two sounds...
in such a binaural
Binaural
Binaural literally means "having or relating to two ears." Binaural hearing, along with frequency cues, lets humans and other animals determine direction of origin of sounds...
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
Haskins Laboratories is an independent, international, multidisciplinary community of researchers conducting basic research on spoken and written language. Founded in 1935 and located in New Haven, Connecticut since 1970, Haskins Laboratories is a private, non-profit research institute with a...
associated with Yale University
Yale University
Yale University is a private, Ivy League university located in New Haven, Connecticut, United States. Founded in 1701 in the Colony of Connecticut, the university is the third-oldest institution of higher education in the United States...
.
Duplex perception was argued as evidence for the existence of distinct systems for general auditory perception
Auditory system
The auditory system is the sensory system for the sense of hearing.- Outer ear :The folds of cartilage surrounding the ear canal are called the pinna...
and speech perception
Speech perception
Speech perception is the process by which the sounds of language are heard, interpreted and understood. The study of speech perception is closely linked to the fields of phonetics and phonology in linguistics and cognitive psychology and perception in psychology...
. However, the same phenomenon can be obtained with slamming doors.