How frequently a preschooler naturally blinks may offer a window into how their brain is maturing and developing self-control. A new study published in Communications Psychology indicates that young children who blink more often per minute tend to perform better on a test of mental flexibility and show more activity in a region behind the forehead important for the task. The findings suggest that spontaneous eye-blink rate could serve as a simple, non-invasive physiological marker of early cognitive and brain development.
Executive function refers to a set of higher-order mental skills that allow people to hold information in mind, resist distractions, and switch flexibly between different rules or goals. These abilities expand rapidly between the ages of three and six and predict later academic performance, social adjustment, and health. This behavioral growth is thought to reflect the maturation of the prefrontal cortex, the outer layer of brain tissue located at the very front of the head just behind the forehead.
A prevailing hypothesis in developmental neuroscience proposes that as children grow, task-related activity in the prefrontal cortex shifts from widespread, diffuse engagement to more focused, specialized recruitment of specific subregions. In adults, this focused prefrontal activity works in tandem with the striatum, a cluster of deeper brain structures involved in movement, reward, and rule learning. Communication along these front-to-deep brain circuits is influenced by dopamine, a chemical messenger produced in the midbrain that is thought to help stabilize goal-relevant information in the prefrontal cortex while allowing the striatum to update mental rules when situations change.
Whether dopamine and these brain circuits play a similar role during the preschool burst in executive function has been difficult to study directly. Standard brain scans used to measure dopamine in adults, such as positron emission tomography, require radioactive tracers and long periods of stillness that are unsuitable for young children. Indirect evidence has hinted at a connection, including a 2018 study by one of the same authors and a colleague, which found that variations in a dopamine-regulating gene in three- to six-year-olds were linked to both rule-switching ability and activity in the upper-right prefrontal cortex.
To track these developing systems non-invasively, a research team led by Ryuta Kuwamizu, an assistant professor at the Institute of Health and Sport Sciences and the Advanced Research Initiative for Human High Performance at the University of Tsukuba, and Yusuke Moriguchi, a professor at the Graduate School of Letters at Kyoto University where he directs the Moriguchi Child Development Lab, examined spontaneous eye-blink rate, defined as how many times a person naturally blinks per minute without any external trigger.
Blinking is closely linked to arousal networks in the brainstem and other subcortical areas, and has been associated in adult and clinical research with dopamine activity and mental flexibility, such as in patients with Parkinson’s disease who experience both dopamine depletion and reduced blinking. In newborns, natural blink rates are often fewer than five per minute.
The collaboration brought together Moriguchi’s research since 2009 on how genetic and socioeconomic factors relate to early prefrontal maturation with Kuwamizu’s prior findings that young adults with higher natural blink rates show stronger cognitive control in studies of physical exercise.
“What caught our attention is that babies blink very rarely, but blink rate increases several-fold during early childhood, moving toward adult levels (around 20 blinks per minute on average), while large individual differences emerge at the same time,” Kuwamizu and Moriguchi told PsyPost. “Because this is the same period in which executive function develops rapidly, we reasoned that if eye-blink rate reflects brain development, these changes might be related to the development of executive function and the prefrontal cortex.”
The researchers tested whether these emerging differences in blink rate relate to cognitive flexibility and prefrontal specialization in 113 Japanese children aged 35 to 80 months (average age 59 months, with 55 girls and 58 boys). The participants were recruited from two preschools in Osaka and Kyoto, exceeding an initial statistical power calculation showing that at least 82 children were needed to detect a medium-sized correlation of 0.30. Data from 10 additional children could not be used because six declined to start, three refused to wear the brain-monitoring headband, and one moved too much to finish. Although the study was not formally preregistered, the authors followed a two-tiered planned analysis strategy and posted their de-identified data and code publicly on the Open Science Framework.
To measure cognitive flexibility, each child played a multi-stage card game known as the Dimensional Change Card Sort task. Across three sessions using different card sets, children sorted picture cards featuring colored shapes by matching each to one of two reference cards during 25-second sorting blocks separated by 15-second rest breaks. In each session, children first sorted cards by color during a pre-switch phase, then switched to sorting by shape during a post-switch phase, and finally completed a mix phase where the rule alternated between color and shape across up to eight trials.
Out of a maximum of 24 trials per phase across the three sessions, children completed an average of 22.0 trials in the pre-switch phase, 22.2 in the post-switch phase, and 21.1 in the mix phase. Switching accuracy was scored as the percentage of correct sorts on the exact trials where the rule changed from the previous trial. Throughout the six-minute session, which was roughly 40 percent rest and 60 percent sorting, a camera positioned 100 to 150 centimeters away recorded the child’s face at 30 frames per second so two trained raters could count natural blinks per minute for 112 children whose eyes remained visible.
While the children sorted cards, the researchers monitored their brain activity using functional near-infrared spectroscopy, a non-invasive optical technique. Children wore a forehead band fitted with light sources and detectors that shone harmless near-infrared light into the scalp to measure changes in oxygenated hemoglobin in the blood, an indicator of local brain activation across 16 channels. These channels covered four subregions of the lateral prefrontal cortex: the left and right dorsolateral prefrontal cortex on the upper outer sides, and the left and right rostrolateral prefrontal cortex positioned lower and closer to the front pole of the brain.
To mitigate distortion from blood flow in the skin or subtle facial movements during blinking, the team applied a mathematical technique designed to separate neural blood oxygen signals from surface physiological noise. They also reviewed synchronized video to exclude the 1.6 percent of trials affected by visible body movement or headband shifting.
Children found the sorting game more challenging once the rules began to shift, with a large drop in accuracy from the initial color phase to the post-switch shape phase and the mixed-rule phase. Older children achieved higher switching accuracy (correlation of 0.68, on a scale where 0 means no relationship and 1 a perfect one) and blinked more frequently per minute (correlation of 0.29). Children under four years old had uniformly low blink rates with minimal variation between individuals, whereas older preschoolers varied widely, with some blinking more than 20 times per minute.
Supporting the team’s main hypothesis, children with higher spontaneous eye-blink rates demonstrated higher switching accuracy on the card task (correlation of 0.35). To test whether this link simply reflected older children both blinking more and sorting cards better, the researchers calculated a partial correlation, a correlation after statistically removing the influence of age. After controlling for age, the correlation remained (partial correlation of 0.22), and it held up in separate analyses that also adjusted for sex and preschool site.
“This suggests that eye-blink rate does not simply increase with age, but may also capture individual differences among children of the same age,” the researchers explained.
Next, the authors used linear mixed-effects models, statistical models that account for repeated measurements from the same child, to analyze how prefrontal activation varied across task phases and subregions. Prefrontal blood oxygen levels showed a moderate increase during the post-switch phase (Cohen’s d of 0.52) and the mix phase compared to the initial pre-switch phase, while the difference between the post-switch and mix phases was not statistically significant. Overall, brain activity was greater in the right hemisphere than the left and greater in the upper dorsolateral region than the lower rostrolateral region.
Adding age in months to the model improved its fit, increasing the variance explained by the fixed experimental factors from 5 percent to 8 percent, though most variation in brain activity remained unexplained. Age interacted with both hemisphere and subregion: older age was associated with higher activation in the right hemisphere and upper dorsolateral region, accompanied by lower activation in the left hemisphere and lower rostrolateral region. Rather than activating the prefrontal surface evenly, older children showed more specialized recruitment of the upper-right prefrontal cortex.
The researchers noted that capturing these patterns with functional near-infrared spectroscopy, or fNIRS, helped show how prefrontal activity differs between younger and older preschoolers.
“What we found most interesting is that we could go as far as examining how these measures relate to patterns of prefrontal activation, as part of the neural basis of executive function,” Kuwamizu and Moriguchi said. “Measuring brain activity in young children is not easy, but with fNIRS we were able to clearly confirm task-related prefrontal activation.”
“Whereas activation was relatively widespread in younger children, older children showed stronger activation in the right dorsolateral prefrontal cortex (rDLPFC), while activation in the left hemisphere and the rostral regions (toward the front of the brain) did not increase or even slightly decreased,” they continued. “Rather than the whole prefrontal cortex becoming uniformly more active, the region important for the task becomes selectively engaged—a pattern known as functional differentiation. Note that these findings are based on cross-sectional data.”
When the researchers tested each of the four prefrontal subregions individually against blink rate and task performance during the rule-switching phases, only the right dorsolateral prefrontal cortex met the statistical threshold adjusted for multiple comparisons. Activity in this upper-right region correlated positively with both spontaneous eye-blink rate (correlation of 0.27 among 111 children) and switching accuracy (correlation of 0.32 among 112 children), whereas correlations in the other three subregions remained below 0.20 and did not reach that threshold.
After controlling for age in months, right dorsolateral prefrontal activity remained positively correlated with both blink rate (partial correlation of 0.21) and switching accuracy (partial correlation of 0.21). By conventional standards, these age-adjusted correlations of 0.21 to 0.22 are modest associations and are smaller than the 0.30 correlation the study was originally sized to detect.
An exploratory mediation analysis, a statistical test of whether one variable helps explain the link between two others, was consistent with the idea that activity in this region forms part of the link between blink rate and switching accuracy, though with data from a single time point it cannot show that one causes the other. In the authors’ reading, these patterns suggest that as front-to-deep brain circuits and the dopamine system mature in early childhood, they support both rising blink rates and more selective recruitment of the upper-right prefrontal cortex. The researchers also propose that children who perform the visual task more efficiently may rely less on left-hemisphere verbal processing or lower-prefrontal exploratory processing.
“Blinking is something anyone can observe, and it can be easily recorded with an ordinary video camera,” the authors noted. “Combined with AI-based automated analysis, it may even allow large-scale studies. In early childhood, a period that is crucial for development and education, eye-blink rate could become one indicator of how executive function is developing.”
“At the same time, this is a group-level tendency, and the relationship is not strong enough to accurately assess individual children,” they added. “Still, we think it is highly meaningful that a simple measure obtained from ordinary video was associated not only with behavior but also specifically with activation in the right dorsolateral prefrontal cortex, a region important for this task.”
There are a few things to keep in mind when interpreting these results. Because the study relied on a cross-sectional design that measured each child only once, the findings cannot establish that rising blink rates or shifting prefrontal activity directly cause gains in cognitive flexibility. Following the same children over several years in a longitudinal study will be needed to determine whether early changes in blink rate track individual developmental trajectories over time.
“In this study, we used eye-blink rate as a window into brain development,” Kuwamizu and Moriguchi emphasized. “At present, there is no evidence that encouraging children to blink more improves their cognitive abilities. Blinking is also influenced by many factors beyond the brain, such as the timing and context of measurement, and some children who blink less still have strong executive function. At this stage, eye-blink rate should not be used to evaluate or diagnose individual children.”
Spontaneous eye blinking is also not a pure readout of brain dopamine. As the authors point out, blink generation involves multiple brainstem and subcortical areas and is influenced by several arousal-related neurotransmitters, including acetylcholine and noradrenaline. Even within the dopamine system, several imaging studies of healthy adults have found little or no link between blink rate and certain measures of dopamine function, and forehead optical sensors cannot reach deep brain areas like the striatum or midbrain.
The study also measured executive function with a single visual card-sorting game and averaged blink counts across a six-minute period rather than tracking split-second blink timing during individual trials. Because physical eye blinks can themselves disturb optical forehead recordings, any residual motion or blood-flow artifacts not fully removed by the signal-separation step could also influence the observed link between blink rate and prefrontal activity. Extending this approach to other self-control tasks and diverse cultural settings will help establish how broadly natural blinking reflects early brain maturation.
“We also hope to examine lifestyle, genetic, and environmental factors that may shape these relationships, such as exercise habits, music, and educational interventions, and to test whether eye-blink rate could serve as a marker for evaluating the effects of such interventions and support,” the researchers said. “Because eye-blink rate can be measured without depending on location or specialized equipment, we also expect this approach to enable research with diverse children around the world, regardless of region or research environment.”
Alongside their work on blinking, the team has been investigating related questions about inner speech and arousal. In a 2026 study in iScience described in a University of Tsukuba news release, the researchers used pupil tracking in adults to show that counting silently in one’s head is accompanied by smaller pupil responses than counting aloud. In a related 2026 paper in Acta Psychologica detailed in a separate University of Tsukuba announcement, the team traced the emergence of silent inner speech in three- to six-year-old children through a mental counting task.
“This study focused on cognitive flexibility, one component of executive function,” Kuwamizu and Moriguchi concluded. “Eye-blink rate may also be linked to many other aspects of children’s mental development, such as other components of executive function, memory, and consciousness. In fact, why we blink at all is still not fully understood. We believe that digging deeper into children’s blinking can offer clues to the world children see and how they behave, and we hope this study will serve as a starting point.”
The study, “Emergent blink rate in early childhood is associated with neural origins of executive function,” was authored by Ryuta Kuwamizu, Nozomi Yamamoto, Kota Otani, and Yusuke Moriguchi.