Blink-and-you-miss-it usually applies to what we see, but according to Concordia University blinking may also impact what we hear. Researchers at the university in Montreal looked at how blinking relates to cognitive processes, including our ability to tune out background noise and focus on speech in noisy environments.
“We wanted to know if blinking was impacted by environmental factors and how it related to executive function,” explained lead author Pénélope Coupal, an honours student at the Laboratory for Hearing and Cognition. Coupal and her co-authors devised two experiments to measure blink rate in relation to speech processing, ambient noise and lighting conditions.
The results showed a consistent decrease in blink rates when participants were listening to speech, an effect that strengthened as background noise levels increased, and held regardless of lighting.
“We don’t just blink randomly,” said Coupal. “In fact, we blink systematically less when salient information is presented.”
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In the first experiment, participants sat in a soundproof room, listening to short spoken sentences through headphones as background noise levels changed from quiet to very loud. Sentences were then verbally repeated to an experimenter to ensure active listening. Participants focused on a cross in front of them throughout the experiment as eye-tracking glasses recorded every blink, capturing the exact timing of each one.
Blink rates dropped consistently while participants were listening to the sentence, compared to before and after. The effect was strongest when background noise was highest, suggesting that blinking decreases the more effort is required to understand speech.
While lighting remained consistent in the first experiment, at a medium brightness, the second experiment introduced three different lighting conditions: dark, medium and bright. The same patterns appeared across all conditions, showing that the change in blink rate is driven by cognitive load, not how much light is entering the eye. Researchers noted that despite a wide range in blink rates across individuals – from 10 times per minute to as much as 70 – the overall trend was clear and statistically significant.
“Our study suggests that blinking is associated with losing information, both visual and auditory,” said co-author Mickael Deroche, an associate professor in the Department of Psychology. With further research to map out exact timing and patterns could allow blink rate to be used as a simple, low-effort tool to assess cognitive function.
