Summary: People blink less when working harder to understand speech in noisy environments, suggesting that blinking is tightly linked to cognitive effort. Across two experiments, blink rates consistently dropped during key moments of listening, especially when background noise made speech difficult to process.
The effect remained stable regardless of lighting conditions, indicating that the change reflects mental load rather than sensory input 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 drop while listening to important speech, especially in noisy settings.
- Lighting Doesn’t Matter: Bright, dim, or dark rooms showed the same cognitive blink suppression effect.
- Useful Metric: Blink timing can serve as a practical measure of cognitive load in real-world environments.
Source: Concordia University
Blinking is a human reflex most often performed without thinking, like breathing.
Although research on blinking is usually related to vision, a new Concordia study examines how blinking is connected to cognitive function such as filtering out background noise to focus on what someone is trying to say to us in a crowded room.
Writing in the journal Trends in Hearing, the researchers describe two experiments designed to measure how eye blinking changes in response to stimuli under different conditions.
They found that people naturally blink less when they are working 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 blink patterns remained stable across different lighting conditions — meaning people blinked just as much whether lighting was bright, dim or dark.
“We wanted to know if blinking was impacted by environmental factors and how it related to executive function,” says 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?”
They found that this was indeed the case.
“We don’t just blink randomly,” says Coupal. “In fact, we blink systematically less when salient information is presented.”
Linking ocular and auditory activity
In the study involving almost 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 quiet to loud.
Using eye-tracking glasses, the researchers recorded every blink and its exact timing as participants listened to the sentences. Each trial was then divided into three time windows: before, during and after each sentence.
They found blink rates consistently dropped while participants listened to a sentence compared to the periods immediately before and after. This blink suppression was especially pronounced in the noisiest conditions, when speech was hardest to understand.
In a follow-up experiment, the researchers tested blinking rates at different SNRs in rooms with dark, medium and bright lighting. The same pattern emerged. This indicated that cognitive demands drive the effect, rather than how much light reaches the eye.
While the researchers noted that blink rates varied between individuals — some participant blinked as little as 10 times per minute, while others may have blinked 70 times per minute — the general trend was visible and significant.
Most previous studies linking ocular function to cognitive effort focused on measuring pupil dilation (pupillometry) and treated blinks as nuisances to be removed from the data. This study reanalyzed existing pupillometry data to focus specifically on blink timing and frequency. The researchers say their findings confirm blink rates can be used as a practical, low-burden metric to measure cognitive function in both laboratory and real-world settings.
“Our study suggests that blinking is associated with losing information, both visual and auditory,” says co-author Mickael Deroche, an associate professor in the Department of Psychology.
“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.”
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. Blink patterns remained the same across dark, dim, and bright lighting, confirming the effect is cognitive, not visual.
A: Yes. Blink timing and frequency offer a simple, low-burden way to track cognitive load in both lab and real-world listening tasks.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this visual and auditory neuroscience research news
Author: Patrick Lejtenyi
Source: Concordia University
Contact: Patrick Lejtenyi – Concordia University
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Reduced Eye Blinking During Sentence Listening Reflects Increased Cognitive Load in Challenging Auditory Conditions” by Pénélope Coupal et al. Trends in Hearing
Abstract
Reduced Eye Blinking During Sentence Listening Reflects Increased Cognitive Load in Challenging Auditory Conditions
While blink analysis was traditionally conducted within vision research, recent studies suggest that blinks might reflect a more general cognitive strategy for resource allocation, including with auditory tasks, but its use within the fields of Audiology or Psychoacoustics remains scarce and its interpretation 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 a window of alertness.
In experiment 1, 21 participants were presented with 80 sentences at different signal-to-noise ratios (SNRs): 0, + 7, + 14 dB and in quiet, in a sound-proof room with gaze and luminance controlled (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 screened for the number of blinks, along with their respective onset and offset. Results showed that blink occurrence decreased during sentence presentation, with the reduction becoming more pronounced at more adverse SNRs.
Experiment 2 replicated this finding, regardless of luminance level. It is concluded that blinks could serve as an additional physiological correlate to listening effort in simple speech recognition tasks, and that it may be a useful indicator of cognitive load regardless of the modality of the processed information.
