Closing your eyes in a noisy room makes you hear worse, not better

You are in a crowded restaurant, struggling to hear the person across the table. Instinct says close your eyes, block out the visual noise, focus. That instinct, according to a new study, is wrong - at least when the background is loud.

Researchers at Shanghai Jiao Tong University tested the common belief that closing your eyes sharpens hearing and found the opposite. In noisy conditions, participants with their eyes closed performed worse at detecting target sounds than those with their eyes open. The study appears in the Journal of the Acoustical Society of America (JASA).

The experiment: four visual conditions, one auditory task

Volunteers listened to sounds through headphones against a background of noise, then adjusted the volume until they could barely detect the target sound over the background. This threshold measurement was repeated under four conditions:

• Eyes closed
• Eyes open, looking at a blank screen
• Eyes open, looking at a still image matching the sound
• Eyes open, watching a dynamic video matching the sound

The results were consistent and counterintuitive. Participants needed higher volumes - meaning they had worse hearing sensitivity - when their eyes were closed compared to when they were open. The best performance came with the matching video: watching dynamic visual content that corresponded to the target sound significantly lowered detection thresholds.

The brain over-filters when you close your eyes

To understand why, the researchers monitored participants' brain activity using electroencephalography (EEG). The explanation turned out to involve a concept called neural criticality - the state in which the brain balances between order and chaos, maximizing its ability to process information.

Closing the eyes shifted the brain toward a more internally focused state that more aggressively filtered incoming signals. In quiet conditions, this heightened filtering might help by reducing neural noise. But in a noisy environment, the brain needs to actively separate a target signal from background sound. The internal focus promoted by eye closure caused the brain to over-filter, suppressing the target along with the noise.

"In a noisy soundscape, the brain needs to actively separate the signal from the background," said author Yu Huang. "We found that the internal focus promoted by eye closure actually works against you in this context, leading to over-filtering, whereas visual engagement helps anchor the auditory system to the external world."

Vision anchors hearing to the real world

The video condition's superiority suggests that multisensory integration - processing visual and auditory information simultaneously - actively enhances auditory detection. The brain appears to use visual information as a kind of anchor, tethering auditory processing to the external environment and counteracting the tendency to filter out faint signals.

The researchers are careful to note that their finding is specific to noisy environments. In quiet settings, the conventional wisdom likely holds: closing your eyes probably does help detect faint sounds, because the aggressive filtering that hurts in noise can help in silence by reducing internal neural chatter.

What comes next: does the visual content have to match?

The study raises a question it does not yet answer: does the visual boost require congruence between what you see and what you hear? The matching video condition outperformed the blank screen, but the experiment did not test mismatched pairings - for example, hearing a drum while watching a bird.

"Does the visual boost come from simply having the eyes open and processing more visual information, or does the brain require the visual and audio information to match perfectly?" Huang said. The team plans to test incongruent pairings in follow-up work to separate the general effects of visual engagement from specific multisensory integration benefits.

Practical take and caveats

The practical implication is straightforward: in noisy environments - restaurants, airports, busy offices, concerts - keeping your eyes open and directed toward the sound source may help you hear better than shutting them. This could have applications for hearing aid design, architectural acoustics, and communication protocols in noisy workplaces.

The study was conducted under controlled laboratory conditions with headphones, which differs from the complex spatial acoustics of real environments. Whether the same effect holds when sounds arrive from specific directions in a three-dimensional space, rather than through headphones, is not yet known. Sample size details were not specified in the press release.