Re: By any other name...

[Bruno Repp <repp@xxxxxxxxxxxxxxxx>]

Dear Richard:

There is a philosophical (or methodological?) problem I've had with 
this effect for a long time: If, as you say, "the interrupting louder 
sound stimulates the same peripheral receptors that would have been 
stimulated if the sound had indeed been present", what proves that 
the sound is actually absent?

Best,
Bruno

> The auditory continuity phenomenon has been the subject of several 
> communications earlier this month, and several names of people 
> associated with this illusion were mentioned.  Massimo Grassi 
> correctly stated that Vicario's name belongs on the list.  He did 
> indeed observe the effect in 1960, naming it "L'effetto tunnel 
> acustico."  But Miller and Licklider seem to have been the first 
> discoverers in 1950.  Several other investigators, unaware of the 
> earlier publications, made their own independent discoveries.  This 
> led to a multiplicity of terms describing the effect including 
> "picket fence effect," "auditory figure ground effect," and more 
> recently, "auditory continuity effect," "auditory induction," and 
> "temporal induction."
>
> The communications this month seem to have limited this phenomenon 
> to the illusory continuity of steady-state tones and tone glides 
> through interruptions by a louder noise.  But this phenomenon is 
> much broader:  portions of any sound can be restored if the 
> interrupting louder sound stimulates the same peripheral receptors 
> that would have been stimulated if the sound had indeed been 
> present.  In everyday life this effect represents a sophisticated 
> process that can restore portions of signals (including speech) if 
> they have actually been masked.  This is accomplished by 
> reallocating a portion of the neural representation of the louder 
> interrupting sound for the perceptual synthesis of the fainter 
> signal.  In support of this mechanism, it had been shown that when 
> illusory restoration of the fainter sound (either a tone or speech) 
> occurred, it was accompanied by a decrease in the loudness of the 
> interrupting sound [R.M. Warren et al., 1994, Auditory induction: 
> Reciprocal changes in alternating sounds.  Perception and 
> Psychophysics, 55, 313-322].
>
> For a review of the literature, see Chapter 6 "Perception of missing 
> sounds" in R.M. Warren, 1999, Auditory Perception: A New Analysis 
> and Synthesis, New York:  Cambridge University Press (a third 
> edition is now in production by Cambridge).


--
Bruno H. Repp
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