Yep, that's right. Our eardrums apparently move to shift our hearing in sync with our eyes!
Jennifer Groh of the Duke University in Durham, North Carolina, together with her team, utilized 16 volunteers to understand better how this happens. Specifically, they've put microphone into the participants' ears to examine how eardrums adjust during saccades. Saccades are fast movements our eyes make when shifting at one place to another.
With this, they found that certain changes of the pressure in ear canal may have been due to the tugging of middle-ear muscles on the eardrum. Hence, when we look at a certain direction (i.e. right), the eardrum on that side (right) gets pulled further into the ear. The other side (left) then gets pushed out.
Look and listen.
What's more is that such adjustment happens as early as 10 milliseconds before the eyes' movement and even continues for about tens of millisecond after the movement stops!
“We think that before actual eye movement occurs, the brain sends a signal to the ear to say ‘I have commanded the eyes to move 12 degrees to the right’,” says Groh. This may be due to our eardrums' effort on preparing our ears hear sounds from a certain direction.
But the real reason still isn't clear. One theory is that it might help the brain add up what we see and hear.
Nonetheless, researchers hope that with this, hearing aids would then have a much better improvement that it almost mimics how we truly hear. “I could imagine a mechanism being incorporated into hearing aids that picks up signals of eyes moving to a new location and tries to amplify the sound at that location,” she says.
Now you can identify better where the sounds your hearing came from. Just focus on where you're looking!
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