Language in Mind

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Web Activity 7.8 The phoneme restoration effect

Phoneme restoration

The next two audio clips illustrate the phoneme restoration effect, an illusion in which a non-speech sound (white noise or a cough) replaces a speech sound within a recognizable word, with the result that people perceive the non-speech sound while also “hearing” the missing speech sound. These examples come from Richard M. Warren, who first studied the effect (Warren, 1970), with stimuli and narration by his colleague James A. Bashford, Jr.

The first demonstration illustrates what happens when the a single sound in the word legislatures is replaced with the sound of a cough.

Audio clip 1

The second clip demonstrates the effect on perception of creating multiple intermittent gaps in the speech stream, and then filling these gaps with noise.

Audio clip 2

The phoneme restoration effect makes it easy to see how we manage to perceive speech fairly well even when we are in a noisy environment that interferes with the perception of individual speech sounds. When the auditory signal is degraded or unclear, our knowledge of words and the sounds they contain comes to the rescue.

Ganong effect

A similar phenomenon is the Ganong effect, in which a sound that is ambiguous between two phonemes is perceived differently depending on the word that contains it.

Listen to the two words in the following audio clips. What is the first sound you hear in each of these words?

Word 1

Word 2

In fact, the first sound in both of these words is identical. But you may have perceived it as a /g/ in the first word and as a /k/ in the second word, simply because these are the sounds you expect to hear in the words gift and kiss.

The next audio clips illustrate the Ganong effect along a broad continuum of voice onset time (VOT) of 11 to 53 ms. (Recall that VOT distinguishes voiced sounds such as /g/ from unvoiced sounds such as /k/.) The initial sound in each pair of words is identical, but many people perceive the two sounds as different from each other.

Pair 1

Word 1

Word 2

Pair 2

Word 1

Word 2

Pair 3

Word 1

Word 2

Pair 4

Word 1

Word 2

Pair 5

Word 1

Word 2

Pair 6

Word 1

Word 2

Pair 7

Word 1

Word 2

The audio clips for the Ganong effect have been provided by Emily Myers, and they represent stimuli from Myers and Blumstein (2008).

References

Myers, E. B., & Blumstein, S. E. (2008) The neural bases of the lexical effect: An fMRI investigation. Cerebral Cortex, 18, 278–288.

Warren, R. M. (1970) Perceptual Restoration of Missing Speech Sounds. Science 167, 392–393.

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