Blinking less: Blinking less in a noisy environment may be a sign the brain is working harder to understand speech, according to new research that suggests eye-blink patterns can reflect mental effort during everyday listening.
In two experiments published in the journal Trends in Hearing, researchers found that people consistently blinked less while listening to spoken sentences, especially when background noise made the speech harder to follow. The effect was linked to listening difficulty, not changes in lighting.
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The study team at Concordia University in Canada monitored 50 adults in a controlled, soundproof setting. Participants were asked to fix their gaze on a cross displayed on a screen while they listened to short sentences through headphones. Background noise levels were adjusted from quiet to increasingly loud, and the researchers tracked the timing and frequency of blinks.
Across conditions, blink rates dropped during the moment a sentence was being played, compared with the period just before and just after. Blink suppression was strongest in the noisiest settings, when understanding speech required the most concentration.
The researchers suggest the brain may reduce blinking to avoid missing important information. “We suppress blinking when important information is coming,” the team noted, arguing that blinks can coincide with brief moments of lost input, visual and possibly auditory.
To test whether environmental factors like light could explain the pattern, a second experiment repeated the listening task under different lighting conditions, ranging from dark to bright. The same blink changes appeared, pointing to cognitive demand, rather than brightness, as the key driver.
The researchers said earlier studies on listening effort often focused on pupil dilation and treated blinks as “noise” in the data. In this work, the team re-examined existing pupil datasets to study blinking directly and argued that blink rate and timing could serve as a simple, low-burden marker of cognitive load both in labs and in real-world settings.
Lead author Pénélope Coupal said the goal was to understand whether blinking changes strategically when people are trying not to miss what’s being said. The findings, she said, suggest blinking is not random and tends to decrease when the brain is processing information that matters.
