Researchers at Concordia University have discovered that people blink less when concentrating on speech amid background noise, highlighting a link between eye behavior and cognitive effort. This pattern persists regardless of lighting conditions, suggesting it's driven by mental demands rather than visual factors. The findings, published in Trends in Hearing, could offer a simple way to measure brain function during listening tasks.
Blinking, an automatic reflex like breathing, plays a subtle role in how the brain processes information, according to a new study from Concordia University. Published in the journal Trends in Hearing in 2025, the research explores how eye blinks relate to cognitive processes, particularly in filtering speech from noisy environments.
The study involved nearly 50 adult participants in a soundproof room, where they listened to short sentences through headphones while viewing a fixed cross on a screen. Eye-tracking glasses recorded blinks as background noise levels varied, creating signal-to-noise ratios from quiet to highly distracting. Blink rates dropped significantly during the sentences themselves, especially when noise made comprehension hardest, compared to periods before and after playback.
"We wanted to know if blinking was impacted by environmental factors and how it related to executive function," said lead author Pénélope Coupal, an Honours student at the Laboratory for Hearing and Cognition. "For instance, is there a strategic timing of a person's blinks so they would not miss out on what is being said?"
A second experiment tested lighting variations—dark, medium, and bright rooms—across similar noise levels. The blink suppression pattern remained consistent, indicating cognitive load, not light exposure, as the driver. Participants varied widely in baseline blink rates, from 10 to 70 times per minute, but the trend was statistically significant.
"We don't just blink randomly," Coupal noted. "In fact, we blink systematically less when salient information is presented."
Co-author Mickael Deroche, an associate professor in the Department of Psychology, emphasized the implications: "Our study suggests that blinking is associated with losing information, both visual and auditory. That is presumably why we suppress blinking when important information is coming."
Unlike prior work that dismissed blinks in favor of pupil dilation measures, this research treats them as indicators of mental effort. Yue Zhang also contributed to the paper, titled "Reduced Eye Blinking During Sentence Listening Reflects Increased Cognitive Load in Challenging Auditory Conditions." The authors propose blinks as a low-effort tool for assessing cognition in labs and everyday scenarios, with ongoing work mapping information loss during blinks led by postdoctoral fellow Charlotte Bigras.
