Summary: People blink less when they try harder to understand speech in noisy environments, suggesting that blinking is closely related to cognitive effort. In two experiments, blink rate consistently decreased during key moments of listening, especially when background noise made speech processing difficult.
The effect remained stable regardless of lighting conditions, indicating that the change reflects mental load rather than sensory information to the eye. The findings highlight blinking as a simple, real-time marker of how hard the brain is working to filter out noise and focus on important information.
Key facts
Effort-based blinking: Blink rates decrease when listening to important speech, especially in noisy environments. Lighting doesn’t matter: bright, dim, or dark rooms showed the same cognitive flicker suppression effect. Useful Metric: Blink time can serve as a practical measure of cognitive load in real-world settings.
Source: Concordia University
Blinking is a human reflex that is most often done without thinking, like breathing.
Although research on blinking is often related to vision, a new study from Concordia examines how blinking is related to cognitive function, such as filtering out background noise to focus on what someone is trying to tell us in a crowded room.
In an article in the journal Trends in Hearing, the researchers describe two experiments designed to measure how blinking changes in response to stimuli under different conditions.
They found that people naturally blink less when they try harder to understand speech in noisy environments, suggesting that the act of blinking reflects the mental effort behind everyday listening. The research further showed that blinking patterns remained stable across different lighting conditions, meaning that people blinked with the same frequency whether the lighting was bright, dim or dark.
“We wanted to know if blinking was affected by environmental factors and how it related to executive function,” says lead author Pénélope Coupal, an honors student in the Hearing and Cognition Laboratory. “For example, is there a strategic time for a person to blink so they don’t miss what is being said?”
They discovered that this was indeed the case.
“We don’t blink randomly,” says Coupal. “In fact, we systematically blink less when salient information is presented.”
Link eye and auditory activity
In the study, which involved nearly 50 adults, participants sat in a soundproof room, fixated on a cross on a screen. They listened to short sentences played through headphones while background noise levels (the signal-to-noise ratio (SNR)) varied from low to high.
Using eye-tracking glasses, the researchers recorded each blink and its exact timing while the participants listened to the sentences. Each trial was then divided into three time periods: before, during, and after each sentence.
They found that blink rate consistently decreased while participants listened to a sentence compared to the periods immediately before and after. This blink suppression was especially pronounced in the noisier conditions, when speech was more difficult to understand.
In a follow-up experiment, the researchers tested flicker rates at different SNRs in dark, medium, and bright lighting rooms. The same pattern emerged. This indicated that cognitive demands drive the effect, rather than the amount of light reaching the eye.
While the researchers noted that blink rates varied between individuals (some participants blinked as few as 10 times per minute, while others may have blinked 70 times per minute), the overall trend was visible and significant.
Most previous studies linking eye function to cognitive effort focused on measuring pupil dilation (pupilometry) and treated blinks as annoyances that needed to be removed from the data. This study reanalyzed existing pupillometry data to specifically focus on blink time and frequency. The researchers say their findings confirm that blink rates can be used as a practical, low-burden metric to measure cognitive function both in the laboratory and in the real world.
“Our study suggests that blinking is associated with the loss of information, both visual and auditory,” says co-author Mickael Deroche, associate professor in the Department of Psychology.
“Presumably that’s why we suppress blinking when important information arrives. But to be completely convincing, we need to map the precise timing and pattern of how visual/auditory information is lost during a blink. This is the logical next step, and postdoctoral fellow Charlotte Bigras is leading a study. But these findings are far from trivial.”
Yue Zhang contributed to this research.
Key questions answered:
A: Because the brain suppresses blinking to avoid missing critical auditory information when cognitive demand is high.
A: No. The flicker patterns remained the same in dark, dim, and bright lighting conditions, confirming that the effect is cognitive, not visual.
A: Yes. Blink time and rate offer a simple, hassle-free way to track cognitive load in both laboratory and real-world listening tasks.
Editorial notes:
This article was edited by a Neuroscience News editor. Magazine article reviewed in its entirety. Additional context added by our staff.
About this research news in visual and auditory neuroscience
Author: Patrick Lejtenyi
Source: Concordia University
Contact: Patrick Lejtenyi – Concordia University
Image: Image is credited to Neuroscience News.
Original research: Open access.
“Reduced flicker during sentence listening reflects increased cognitive load in challenging listening conditions” by Pénélope Coupal et al. Trends in hearing
Abstract
Reduced flicker during sentence listening reflects increased cognitive load under challenging listening conditions
While blink analysis was traditionally performed in vision research, recent studies suggest that blinks could reflect a more general cognitive strategy for resource allocation, including auditory tasks, but their use in the fields of audiology or psychoacoustics remains scarce and their interpretation is largely speculative.
It is hypothesized that as listening conditions become more difficult, the number of blinks would decrease, especially during stimulus presentation, because it reflects an alert window.
In experiment 1, 21 participants were presented with 80 sentences with different signal-to-noise ratios (SNR): 0, + 7, + 14 dB and in silence, in a soundproof room with controlled gaze and luminance (75 lux). In experiment 2, 28 participants were presented with 120 sentences at only 0 and +14 dB SNR, but in three luminance conditions (dark at 0 lux, medium at 75 lux, bright at 220 lux).
Each pupil trace was manually reviewed to determine the number of blinks, along with their respective onset and offset. The results showed that blink frequency decreased during sentence presentation, and the reduction became more pronounced at more adverse SNRs.
Experiment 2 replicated this finding, regardless of luminance level. It is concluded that blinking could serve as an additional physiological correlate of listening effort in simple speech recognition tasks, and that it may be a useful indicator of cognitive load regardless of the modality of the information processed.
