Detail

Obviously, such sounds cannot be heard by humans, so a special highly sensitive microphone is needed to capture them. It was placed directly into the ear. An eye-tracking device recorded where the participant’s eyeballs moved to compare them with the sounds detected by headphones with built-in microphones. Scientists then analyzed the ear sounds and found unique signatures for different directions of movement. This allowed them to decode ear sounds and calculate where people were looking just by looking closely at the sound wave.

As Professor Jennifer Groch points out, the cause of sounds is eye movement, which causes the middle ear muscles to contract. These sounds can occur when eye movements stimulate the brain to contract middle ear muscles, which normally help reduce loud sounds, or hair cells, which help amplify low sounds. The assumption made by scientists in 2018 was confirmed during a series of experiments with the participation of 16 volunteers.

After all researchers have learned to identify the object at the center of attention by sound in the ears participants accurately identify sounds in the process of transferring gaze from one object to another.

We believe this is part of the system that allows the brain to associate the locations of objects and sounds, even though our eyes can move and our head and ears cannot.
– says Jennifer Groh.

This is how the imperceptible “squeak” of the ears, arising due to the movement of the eyes, is heard: video

It also works the other way around. By knowing where someone was looking, Groh and his team were able to predict what the ear sound waveform would look like.

The team is now beginning to investigate whether these ear sounds play a role in perception. They will also focus on how auditory eye movement sounds may differ in people with hearing or vision loss.

Understanding the relationship between soft ear sounds and vision could lead to the development of new clinical hearing tests.