Speech shadowing

Speech shadowing is a psycholinguistic experimental technique in which subjects repeat speech at a delay to the onset of hearing the phrase. The time between hearing the speech and responding, is how long the brain takes to process and produce speech. The task instructs participants to shadow speech, which generates intent to reproduce the phrase while motor regions in the brain unconsciously process the syntax and semantics of the words spoken. Words repeated during the shadowing task would also imitate the parlance of the shadowed speech.

The reaction time between perceiving speech and then producing speech has been recorded at 250 ms for a standardised test. However, for people with left dominant brains, the reaction time has been recorded at 150 ms. Functional imaging finds that the shadowing of speech occurs through the dorsal stream. This area links auditory and motor representations of speech through a pathway that starts in the superior temporal cortex, extends to the inferior parietal cortex and ends with the posterior and inferior frontal cortexes, specifically in Broca's area.