A new study published in Communications Psychology indicates that how often a preschooler blinks naturally may offer a window into how their brain is maturing and developing self-control. The researchers found that children who blink more often per minute tended to perform better on a test of mental flexibility and showed greater activity in a region behind the forehead important for the task.
Executive function encompasses a suite of higher‑order mental skills that enable children to hold information in mind, resist distractions, and switch between different rules or goals. These abilities expand rapidly between the ages of three and six and are predictive of later academic success, social adjustment, and health. The researchers note that this growth mirrors maturation of the prefrontal cortex, the brain’s frontmost area just behind the forehead.
As children grow, theories about prefrontal development suggest task‑related activity shifts from diffuse engagement to more focused recruitment of specific subregions. In adults, the prefrontal cortex interacts with deeper brain structures such as the striatum, with dopamine thought to help stabilise relevant information while enabling rule updates when circumstances change. Directly studying this in preschoolers, however, has posed challenges because standard adult brain imaging techniques are not suitable for young children.
To pursue this question non‑invasively, a team led by Ryuta Kuwamizu of the University of Tsukuba and Yusuke Moriguchi of Kyoto University examined spontaneous eye‑blink rate—how many times a person blinks per minute without external triggers.
Blinking is linked to arousal networks in the brainstem and other subcortical areas and has long been associated with dopamine activity and mental flexibility in adults, including observations that dopamine depletion can coincide with reduced blinking. In newborns, the natural blink rate is typically under five per minute.
The researchers brought together Moriguchi’s long‑running work on how genetics and socioeconomic factors relate to early prefrontal maturation with Kuwamizu’s findings that higher blink rates in young adults relate to stronger cognitive control in exercise studies.
“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,” the pair 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 team tested 113 Japanese children aged 35 to 80 months (average age 59 months; 55 girls and 58 boys), recruited from two preschools in Osaka and Kyoto. The study exceeded the initial statistical power calculation, which had suggested at least 82 children were needed to detect a moderate correlation of around 0.30. Data from 10 additional children could not be utilised due to various practical issues, and 112 children contributed eye data visible enough for analysis.
To measure cognitive flexibility, each child participated in a multi‑stage card game known as the Dimensional Change Card Sort task. Across three sessions with different card sets, children sorted picture cards by colour or shape in blocks, with rule switches occurring across pre‑switch, post‑switch, and mix phases over about six minutes, including short rests.
A camera positioned about a metre away recorded the children’s faces at 30 frames per second so two trained raters could count natural blinks per minute during the six‑minute session. In parallel, the researchers used functional near‑infrared spectroscopy to track brain activity, with a forehead band containing light sources and detectors covering 16 channels across four prefrontal subregions.
To guard against distortions from skin blood flow and facial movements during blinking, the team employed signal‑separation techniques and reviewed video to exclude trials affected by movement or headband shifting, amounting to about 1.6 per cent of trials.
As expected, children found the rule switches more challenging, with a drop in accuracy from the initial colour phase to the post‑switch phase and the mixed phase. Older preschoolers tended to beat the younger ones in switching accuracy (a correlation of 0.68 with age) and also blinked more often per minute (0.29 correlation).
Crucially, those with higher spontaneous blink rates tended to perform better on the switch task (a correlation of 0.35). After statistically controlling for age, the link persisted (partial correlation of 0.21), and it remained when adjusting 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.
Using linear mixed‑effects models to account for repeated measurements, the team found prefrontal activation rose moderately during the post‑switch and mix phases compared with the pre‑switch phase. Activation was generally greater in the right hemisphere and higher in the upper dorsolateral prefrontal cortex than in the lower rostrolateral region.
Introducing age into the models improved the fit, with older children showing more selective recruitment of the upper‑right prefrontal cortex. The authors noted that, while this demonstrates functional differentiation, the findings come from cross‑sectional data and cannot map trajectories for individual children.
When examining the four prefrontal subregions separately against blink rate and switching performance, only the right dorsolateral prefrontal cortex reached the stringent statistical threshold after correction for multiple comparisons. Activation in this region correlated positively with both spontaneous blink rate (0.27) and switching accuracy (0.32) across 111–112 children, with age adjustments yielding partial correlations of around 0.21 in both cases.
An exploratory mediation analysis suggested that activity in this region may connect blink rate with switching success, though with data from a single time point it cannot establish causation. The authors propose 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.
“Blinking is something anyone can observe, and it can be easily recorded with an ordinary video camera,” the researchers 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.”
They added: “At the same time, this is a group‑level tendency, and the relationship is not strong enough to accurately assess individual children. Still, we think it is highly meaningful that a simple measure obtained from ordinary video was associated not only with behaviour but also specifically with activation in the right dorsolateral prefrontal cortex, a region important for this task.”
The researchers also stressed that blink rate is not a pure readout of dopamine. Blink generation involves multiple brain regions and is influenced by several arousal‑related neurotransmitters, and forehead sensors cannot reach deep brain areas such as the striatum or midbrain. They caution that measuring blink rate over a six‑minute period and averaging across trials may miss trial‑by‑trial blink timing.
They emphasised that extending the approach to other self‑control tasks and diverse cultural settings will help establish how broadly natural blinking reflects early brain maturation. They also expressed interest in exploring how lifestyle, genetic and environmental factors—such as exercise, music and education—might shape these relationships and whether eye‑blink rate could serve as a marker for evaluating such interventions.
Beyond blinking, the team has pursued related questions about inner speech and arousal. In a 2026 iScience study, pupil tracking in adults showed smaller pupil responses when counting silently compared with counting aloud, while a separate Acta Psychologica paper described the emergence of silent inner speech in three‑ to six‑year‑olds during a mental counting task.
In sum, the authors describe their work as a step toward understanding the neural bases of executive function in early childhood. They caution that while the findings are promising, more longitudinal work is needed to determine how blink rate and prefrontal activation relate to individual developmental trajectories over time.
Emergent blink rate in early childhood is associated with neural origins of executive function, the study’s authors are Ryuta Kuwamizu, Nozomi Yamamoto, Kota Otani, and Yusuke Moriguchi.
