Why Closing Your Eyes Doesn’t Always Facilitate You Hear Better

When attempting to focus on a faint sound, many people instinctively close their eyes, believing that eliminating visual distractions enhances auditory concentration. However, this common practice doesn’t always improve hearing, particularly in noisy environments. Recent research challenges the long-held assumption that shutting out sight automatically sharpens sound perception.

The Study: Testing Hearing in Noisy Conditions

A study published by the Journal of the Acoustical Society of America, on behalf of the Acoustical Society of America, investigated whether closing the eyes truly improves hearing when background noise is present. Researchers at Shanghai Jiao Tong University examined the impact of visual input on sound detection.

Participants listened to a range of sounds through headphones while simultaneously experiencing background noise. Their task involved adjusting the volume of each sound until it was barely audible above the noise. The experiment incorporated several visual conditions: eyes closed, eyes open with a blank screen, viewing a still image related to the sound, and watching a dynamic video corresponding to the sound.

Closing Eyes vs. Visual Cues: Unexpected Results

The study’s findings contradicted popular belief. According to author Yu Huang, “We found that, contrary to popular belief, closing one’s eyes actually impairs the ability to detect these sounds.” Conversely, viewing a video that matched the sound significantly improved hearing sensitivity. Rather than aiding concentration, closing the eyes hindered the ability to discern faint sounds in noisy settings, while relevant visual input proved beneficial.

Brain Activity and Over-Filtering

To understand these results, researchers used electroencephalography (EEG) to monitor brain activity during the tests. They discovered that closing the eyes shifts the brain into a state of neural criticality, increasing the strength of information filtering. This heightened filtering doesn’t just reduce background noise; it can similarly suppress the target sounds individuals are trying to hear.

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

When Does Closing Your Eyes Help?

The researchers noted that the negative effect of closing your eyes appears to be specific to noisy environments. In quieter conditions, closing the eyes may still enhance the detection of subtle sounds. However, given that everyday life often involves significant background noise, keeping your eyes open may be a more effective strategy in many situations.

Future Research: The Connection Between Sight and Sound

The research team plans to continue investigating the interplay between vision and hearing. A key question is whether the benefit stems simply from having visual input or from seeing something that corresponds to the sound. “Specifically, we want to test incongruent pairings – for example, what happens if you hear a drum but see a bird?” said Huang. “Does the visual boost reach from simply having the eyes open and processing more visual information, or does the brain require the visual and audio information to match perfectly? Understanding this distinction will help us separate the general effects of attention from the specific benefits of multisensory integration.”