Researchers at Concordia University have conducted a study exploring the relationship between blinking and cognitive effort when listening to speech in noisy environments. The findings, published in Trends in Hearing, indicate that people blink less frequently when trying to understand speech amid background noise, suggesting that blinking may reflect the mental effort required for listening.
The research team carried out two experiments involving nearly 50 adult participants. During the first experiment, individuals sat in a soundproof room and listened to short sentences through headphones while varying levels of background noise were introduced. Participants focused on a cross displayed on a screen as their blinks were recorded using eye-tracking glasses. The timing of each blink was analyzed before, during, and after each sentence.
Results showed that blink rates decreased significantly while participants listened to sentences compared to the periods before and after hearing them. This reduction in blinking was most pronounced under the noisiest conditions, where understanding speech was most difficult.
A second experiment examined whether lighting conditions influenced blinking patterns by testing participants in rooms with different brightness levels. The same trend emerged regardless of lighting, indicating that cognitive demand—rather than light exposure—was responsible for changes in blink rate.
"We don't just blink randomly," says Coupal. "In fact, we blink systematically less when salient information is presented."
Co-author Mickael Deroche, associate professor in the Department of Psychology, commented: "Our study suggests that blinking is associated with losing information, both visual and auditory." He added: "That is presumably why we suppress blinking when important information is coming. But to be fully convincing, we need to map out the precise timing and pattern of how visual/auditory information is lost during a blink. This is the logical next step, and a study is being led by postdoctoral fellow Charlotte Bigras. But these findings are far from trivial."
Blink rates varied among individuals—from as few as 10 times per minute up to 70—but the overall trend remained significant across all participants.
Most previous studies examining ocular function in relation to cognitive effort have focused on pupil dilation (pupillometry) and typically treated blinks as irrelevant data points. This new analysis instead highlights blink timing and frequency as practical indicators of cognitive function both in laboratory settings and potentially real-world situations.
Yue Zhang also contributed to this research.
