Sitting in a corner reading silently—as you might be doing with this post, for example—turns out to be impossible. Though you’re not making any sound, you’re likely imagining a voice speaking the words within your head. Reading silently combines different sensory systems, the auditory and the visual, SciCurious explains. But is this auditory component of reading silently a necessary component of this activity or just something that we insert into our heads to aid us in comprehension?
Luckily, there is a small population of people with electrodes implanted into their heads that can help answer this question. (Most of these people have severe epilepsy and the electrodes are part of their treatment). Researchers asked four of these people to read a story silently and listen to a voice giving them instructions. The part of their auditory cortex that usually responds to speech also processed the written words as if they were spoken.
The authors think their work shows that we all possess an “inner voice” when reading quietly to ourselves, suggesting that silent reading can never be silent—at least to our brains.
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