Closing your eyes doesn’t necessarily improve hearing
Have you ever squinted your eyes shut trying to hear something important? Many people do this instinctively, because it seems like if you remove the unnecessary input, the brain will focus on sound. Makes sense, right? But Chinese scientists found that it doesn’t work — with closed eyes, we actually hear worse, not better. The brain is simply wired that way, and no amount of willpower can change it.
Why Everyone Thinks Closing Your Eyes Improves Hearing
Our brain simultaneously processes vision, hearing, touch, and other channels. So it’s logical to assume that if you switch off vision, the freed-up resources should enhance hearing. This is exactly the reasoning behind the widespread belief that the brain can only process a limited amount of information, and if you remove visual distractions, spare capacity becomes available for auditory tasks.
Most people instinctively close their eyes when trying to focus on a quiet sound. Many of us were told since childhood that closing your eyes helps you hear better. It seems so obvious that few people stop to question whether it actually works.
However, researchers from Shanghai Jiao Tong University decided to test this idea experimentally. They asked participants to identify different sounds against background noise with their eyes open and closed. The results were unexpected, and they were published in The Journal of the Acoustical Society of America.
How Scientists Tested the Connection Between Vision and Hearing
The experiment involved 25 volunteers. They had to identify one of five target sounds: a canoe paddle splash, a drum beat, a lark singing, a train rumble, or keyboard typing against background noise at 70 decibels. For reference, 70 dB is roughly the volume of a busy street or a noisy restaurant.
Volunteers listened to sounds through headphones and adjusted the volume of the target signal until it became barely distinguishable. The test was conducted under four conditions: with eyes closed, with eyes open facing a blank screen, while viewing a static image related to the sound, and while watching a video corresponding to the sound. The volume level at which the participant could distinguish the sound with eyes open facing a blank screen became the baseline for comparison.
What the Experiment Showed: Closing Your Eyes Worsens Hearing
The results defied expectations. When participants closed their eyes, the target sound had to be made on average 1.32 decibels louder for them to hear it. Simply put, with closed eyes, people heard worse than when looking at a blank screen.
Visual cues, however, worked in the opposite direction. When viewing a static image related to the sound, participants recognized it at a volume 1.6 dB below baseline. The effect of video was even more pronounced, as it allowed participants to hear the sound at a volume 2.98 decibels below baseline.
The difference between closed eyes and video was more than 4 dB — a noticeable gap in hearing sensitivity. It turns out that vision doesn’t distract the brain from hearing — it helps it latch onto the right signal.
The more visual information the participant received, the better they recognized sounds
Why the Brain Hears Worse With Closed Eyes
To understand the mechanism, scientists fitted participants with EEG helmets (electroencephalographs) and tracked brain activity during each test.
It turned out that closing your eyes shifts the brain into a mode where it begins to more aggressively filter incoming signals. Imagine turning noise cancellation in your headphones to maximum — and it removes not only background hum but also the voice of the person you’re talking to.
This is exactly what happens in the brain — the filtering isn’t limited to background noise; it also suppresses the very sounds the person is trying to hear. The brain, deprived of a visual anchor, shifts to an internal focus and begins to muffle the entire outside world.
But when the eyes are open and there is an image or video related to the sound in front of them, visual information anchors the auditory system to reality and helps the brain separate the signal from the noise.
Does Hearing Actually Improve, or Does the Brain Just Fill in the Sound?
However, the results come with an interesting catch. If a person watches a video of a canoe while simultaneously hearing a splash, doesn’t the brain simply start filling in the sound before it actually becomes audible? In other words, does real hearing improve, or does the brain create an illusion? The study authors plan to investigate this in future experiments.
We want to test mismatched pairs — for example, what happens if a person hears a drum but sees a bird?
This is an important clarification. For now, we know that visual cues help, but we don’t fully understand whether this involves genuine hearing enhancement or multisensory integration — the brain’s ability to combine data from different senses into a unified picture.
EEG allowed scientists to see how the brain changes its filtering mode when eyes are closed
When Closing Your Eyes Does Help You Hear
The study doesn’t refute previous data showing that in a quiet environment, closing your eyes can indeed help you focus on sounds. Closing your eyes in a completely quiet room is still a viable strategy. But in a noisy environment like a café, it works against you.
It’s also worth remembering that people with long-term vision loss do develop sharper hearing over time, but this is the result of long-term brain reorganization, not simply closing one’s eyes.
