Speech shadowing

Speech shadowing is an experimental technique in which subjects repeat speech immediately after hearing it (usually through earphones). The reaction time between hearing a word and pronouncing it can be as short as 254 ms or even 150 ms. This is only the delay duration of a speech syllable. While a person is only asked to repeat words, they also automatically process their syntax and semantics. Words repeated during the practice of shadowing imitate the parlance of the overheard words more than the same words read aloud by that subject. The technique is also used in language learning.

Functional imaging finds that the shadowing of nonwords occurs through the dorsal stream that links auditory and motor representations of speech through a pathway that starts in the superior temporal cortex, goes to the inferior parietal cortex and then the posterior inferior frontal cortex (Broca's area).

Speech shadowing was first used as a research technique by the Leningrad Group led by Ludmilla Andreevna Chistovich in the late 1950s. It has been used in research upon speech perception and stuttering.

The speech shadowing technique is used in dichotic listening tests. During these tests, subjects are presented with two different messages, one in their right ear and one in their left. The participants are often asked to focus on only one of the different messages and this is where the speech shadowing technique is used. Participants are instructed to shadow the attended message by repeating it out loud with a delay of a few seconds between hearing a word and repeating the word. The speech shadowing technique is significant for these experiments because it ensures that the subjects are attending to the desired message.

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