Six public schools are assigned to three conditions: two schools will use physically active lessons, two will use physically active breaks and two will serve as controls. First-grade students will be followed from 2022 through 2026. Classroom teachers will deliver the interventions twice each week. Physically active lessons will incorporate movement into school content through teaching methods that involve movement. Physically active breaks will not be tied to academic content and will consist of exercises averaging five minutes, with the stated aim of interrupting sedentary behavior and promoting moderate-to-vigorous movement.

The primary outcomes are cognitive development, measured through computerized tests assessing executive functions, and academic performance, assessed through teachers’ grades and national and state examinations. Secondary outcomes include anthropometry, physical activity level, sedentary behavior, eating habits, sleepiness, quality of life and students’ perception of school. The cluster-randomized design compares interventions delivered across schools rather than evaluating individual students in isolation. The trial was retrospectively registered in the Brazilian Clinical Trials Registry on January 9, 2025, under identifier RBR-10zxwdrh.

The protocol’s stated aim is to provide information about the potential longer-term effects of classroom physical activity strategies, particularly in a setting outside high-income countries. However, the available abstract presents planned methods and expected information rather than completed efficacy results. It does not provide the number of participating students, numerical estimates of intervention effects, or outcome data for any study group. The evidence therefore supports describing the trial’s population, assignments, interventions, follow-up period and measurement plans, but not claiming cognitive, academic, health or educational benefits from physically active lessons or breaks.

Subject of Research: Protocol for a cluster-randomized trial of classroom physical activity interventions in first-grade students in Aracaju, Brazil

Article Title: Effects of physically active lessons and physically active breaks on cognitive development and academic performance of schoolchildren: protocol for a cluster randomized clinical trial

Article References: Gandarela, L., Melo, J. C. N., Oliveira, D. N., Ywgne, J., Tejada, J., & Silva, D. R. (2026). Effects of physically active lessons and physically active breaks on cognitive development and academic performance of schoolchildren: protocol for a cluster randomized clinical trial. BMC Pediatrics. https://doi.org/10.1186/s12887-026-07638-0

Image Credits: AI Generated

DOI: 10.1186/s12887-026-07638-0

Keywords: cluster-randomized trial, study protocol, schoolchildren, physically active lessons, active breaks, cognitive development, academic performance, Aracaju, Brazil, public schools, Effects, physically

Researchers Zi Jun Leong and Norulhuda Ismail of Universiti Teknologi Malaysia have constructed what they call the Integrated Cognitive-Mathematical-Technological, or ICMT, Framework. It weaves together three strands of scholarship that are usually treated separately: Jean Piaget’s theory of cognitive development, John Mason’s model of mathematical thinking processes, and the literature on calculators as cognitive tools. The target population is Malaysian Form 4 students aged 15 to 16, and the immediate proving ground is the quadratic functions topic in the national KSSM curriculum.

The urgency behind the work is stark. In the PISA 2022 assessment, only 41 percent of Malaysian students demonstrated basic mathematical reasoning skills, well below the OECD average of 69 percent. Recent TIMSS results point in the same direction, showing performance in mathematical reasoning that remains under international benchmarks. Malaysia’s Education Blueprint 2013-2025 explicitly prioritizes higher-order thinking skills, defined as the analysis, evaluation, and creation of mathematical solutions to non-routine problems, yet classroom practice has not closed the gap between policy and performance.

The authors argue that the missing ingredient is integration. Developmental theories such as Piaget’s tend to remain abstract, mathematical thinking models often lack any account of technological mediation, and technology integration efforts tend to focus on technical proficiency rather than cognitive growth. Existing frameworks each capture only part of the picture. TPACK describes what teachers need to know but says little about student cognition, while problem-based learning models emphasize authentic tasks without developmental sequencing. The ICMT Framework is designed to bind all three dimensions into a single causal pathway.

The developmental strand rests on Piaget’s formal operational stage, which typically begins around age 12 and equips adolescents with abstract thinking, hypothetical-deductive reasoning, propositional logic, and systematic problem-solving. Crucially, the framework adopts what the authors call a developmental potential model: rather than assuming students have already mastered formal reasoning, it designs tasks that actively cultivate it. This matters because cognitive readiness varies widely among individuals, and contemporary research confirms that adolescence is a critical period for the maturation of the executive functions and reasoning capacities that complex mathematics demands.

The mathematical strand comes from Mason’s four interlocking processes: specialising, examining specific cases to understand a general problem; generalising, identifying patterns across cases and formulating rules; conjecturing, making informed hypotheses from observed patterns; and convincing, justifying claims with argument and proof. These processes operate cyclically, and Malaysian research indicates that students struggle most with conjecturing and convincing, leaning on memorized procedures instead of constructing their own justifications. Mason’s framework offers observable, teachable behaviours that map cleanly onto Piagetian capacities, which is precisely why the authors chose it over alternatives such as Polya’s heuristics or Schoenfeld’s metacognition.

The technological strand reframes the calculator entirely. Drawing on cognitive load theory, the framework assigns the device specific cognitive functions at each phase of Mason’s cycle. In specialising, table mode rapidly generates multiple test cases, offloading arithmetic so students can hunt for patterns. In generalising, graphing features externalize patterns so an entire class can see and discuss them. In conjecturing, parameter manipulation turns hypothesis testing into quick what-if experiments. In convincing, the calculator supplies numerical and graphical evidence. In this role the calculator becomes what researcher Paul Drijvers terms a mediational tool, one that does not merely accelerate computation but actively shapes mathematical thinking.

Applied to quadratic functions, the instructional sequence unfolds in four phases. Students first use the calculator to solve equations with varying coefficients and record organized tables of results. They then graph families of quadratics and observe how parameter changes alter the curves, generating generalizations about coefficients. Next they conjecture conditions for real roots, such as discriminant requirements, and test their hypotheses against fresh equations. Finally, convincing splits into two sub-stages: empirical convincing, where calculator evidence builds inductive confidence, and deductive convincing, where students derive the quadratic formula or prove discriminant conditions by completing the square, using the calculator only to verify finished proofs. Assessment rubrics reinforce the distinction, awarding partial credit for calculator evidence but requiring logical derivation for full justification, so that students never mistake the observation that a pattern held in twenty examples for the algebraic necessity that it must always hold.

The authors are candid about the risks. Over-reliance on calculators can produce what Drijvers calls an instrumental genesis deficit, in which the tool’s efficiency undermines basic understanding. Graphical and numerical output can create an illusion of understanding, substituting empirical verification for genuine proof. Differential access to advanced models raises equity concerns, and success hinges on teachers who can mediate the boundary between thinking with a calculator and merely computing with one. The framework counters these dangers through design constraints: calculators are assigned specific cognitive functions, students must explain their reasoning before using the device for verification, and assessment evaluates both process and product. The framework also acknowledges its own limits, applying more naturally to algebra and functions than to geometric proof or statistics, and assuming reliable technology access that under-resourced and rural schools may lack.

Because the ICMT Framework is currently a propositional model, the authors propose a staged validation agenda: expert panels assessing content validity, pilot implementations in two to three Malaysian classrooms with teacher coaching, a quasi-experimental study comparing ICMT instruction with traditional teaching on TIMSS-like reasoning tasks, and a longitudinal study tracking national examination results, STEM enrolment, and the development of formal operational reasoning. They are now seeking funding and institutional partnerships to carry the work forward. If the validation succeeds, the payoff could be substantial, because scientific calculators are inexpensive, already permitted in Malaysian examinations, and already sitting in classrooms. A three-level technology spectrum, from standard scientific calculators to graphing calculators to computer algebra systems, would let schools upgrade hardware without changing the underlying pedagogy. In an era when education technology debates often centre on expensive tablets and artificial intelligence, the idea that a decades-old, pocket-sized device could be reprogrammed, in a pedagogical sense, into an engine of higher-order thinking is a quietly radical proposition, and one that could travel well beyond Malaysia to any education system wrestling with the gap between ambitious policy and everyday practice.

Subject of Research: A theoretical framework integrating Piaget's cognitive development theory, Mason's mathematical thinking processes, and calculator technology to foster higher-order thinking skills in secondary mathematics

Article Title: An integrated cognitive mathematical technological framework for calculator assisted higher order thinking skills instruction in secondary mathematics

Article References: Leong, Z. J., & Ismail, N. (2026). An integrated cognitive mathematical technological framework for calculator assisted higher order thinking skills instruction in secondary mathematics. Discover Education, 5(1), Article 1195. https://doi.org/10.1007/s44217-026-02304-0

Image Credits: AI Generated

DOI: 10.1007/s44217-026-02304-0

Keywords: higher-order thinking skills, scientific calculator, mathematics education, Piaget, cognitive development, ICMT framework, secondary mathematics, quadratic functions, PISA, TIMSS, educational technology, Malaysia

The review, which followed the PRISMA-ScR checklist for scoping reviews, searched seven databases including APA PsycINFO, ERIC, Scopus, and Web of Science for publications between 1990 and September 2025. Rather than simply searching for the word Africa—a term the authors deliberately excluded because it would pull in studies of African American learners in the United States—they combined executive function keywords such as inhibitory control, working memory, cognitive flexibility, and self-regulation with the names of each of the 54 African countries and eight territories. Supplementary searches of reference lists, direct contact with authors, and an international webinar on executive function in Sub-Saharan Africa added 107 more candidate studies. After screening, 311 papers underwent full-text reading and 129 were excluded, leaving the final corpus of 182 studies.

The geographic picture that emerged was starkly lopsided. Although the included studies spanned 27 African countries, from Botswana and Burkina Faso to Tunisia and Zambia, nearly half of all research came from just three nations: South Africa accounted for 33.9 percent of studies with 62 papers, Ghana contributed 12 percent with 22, and Kenya 6.6 percent with 12. Participants ranged in age from six months to 79 years, with sample sizes between eight and 3,867 people. The earliest eligible study was published in 2001, and publication frequency has climbed since then, peaking in 2022—a sign of growing interest, but from a very low baseline compared with the more than three million Google Scholar hits returned for executive function development research generally.

Equally striking was who conducted the work. More than half of the first authors were affiliated with institutions outside the African continent, and over 56 percent of recorded funding for first authors came from external sources. The authors argue this pattern matters scientifically, not just politically: researchers embedded in local contexts can contextualize the cognitive processes under investigation, develop culturally grounded measures, and move the field beyond extending minority-world research questions and paradigms to new populations. They call for what they describe as Africanized perspectives on executive function, developed with meaningful involvement from local researchers.

On the conceptual level, the news was more encouraging. Most of the 182 studies converged on a broadly consistent definition of executive function as a higher-order cognitive process responsible for regulating deliberate behavior—the capacity to act intentionally rather than automatically. But beneath that consensus lay considerable heterogeneity in how the construct was modeled. A third of the studies, 61 papers or 33.5 percent, treated executive function as tripartite, following the influential framework of inhibitory control, working memory, and cognitive flexibility established by Miyake and colleagues in 2000. Another 36 percent adopted a domain-general model, treating executive function as one facet of general cognition without decomposing it, while 16 studies focused specifically on working memory. Only five studies used a strictly unitary model and five a dual-component model, and 30 papers specified no model at all.

This fragmentation has practical consequences. The weight of evidence from high-income settings suggests the three-component model fits data reasonably well after the preschool years, whereas a single-factor model prevails in early childhood, and the review found that African studies followed a similar pattern, with unitary models more common for younger samples. But whether the same developmental timeline holds across cultures remains an open question—one the authors say can only be answered with more data from majority-world settings, where most of the world’s population actually lives.

Methodologically, the field in Africa leans heavily on imported tools. Ninety-five percent of the studies—173 of 182—adopted or adapted measures developed outside the continent, and 161 studies used task-based measures rather than interviews or self-reports. Experiments and cross-sectional designs dominated, with 98 experimental and 42 cross-sectional studies, compared with just 22 longitudinal designs and 13 randomized controlled trials. Most data collection took place in schools, which accounted for 45.6 percent of study locations. Convergence between different types of measures was mixed: one study found positive correlations between assessor reports and direct assessments, while others found no agreement between report-based and task-based measures at all.

There were notable exceptions to the imported-tool pattern. One research team replaced the classic Marshmallow test with a culturally relevant self-regulation task involving puff-puff, a locally familiar deep-fried dough, in a study with Cameroonian children. A handful of others used locally designed performance-based measures, and two studies interviewed preschool teachers about how they perceive executive function behaviors in children. Where measures were formally validated for local use—including the Early Learning Outcomes Measure in South Africa, the Childhood Executive Functioning Inventory in Kenya, the Arabic version of the BENCI battery in Egypt, and tablet-based assessments in Ghana and Tanzania—they generally showed good reliability and validity, suggesting adaptation is feasible when done carefully.

The findings on how executive function relates to context and outcomes were the most complicated part of the picture. Positive associations emerged with parental education, family stimulation, play behaviors, early childhood education, physical activity, and access to school meals. Negative associations appeared with punitive school environments, parental maltreatment, teacher burnout, maternal alcohol consumption during pregnancy, and stunting. But other results defied expectations: in one Nigerian study, children who had experienced parental loss actually showed enhanced working memory, and in South African samples, exposure to violence and adverse childhood experiences was not associated with self-regulation at all. The link between executive function and academic skills was equally mixed—working memory predicted numeracy, literacy, and school completion in one study, while in others none of the three components predicted literacy or numeracy outcomes.

Intervention evidence was similarly inconsistent. Teacher training programs, executive function games such as red-light purple-light, expressive writing exercises, zinc and micronutrient supplementation, and participation in a public works safety net showed no consistent benefits for children’s executive function. Yet yoga and aerobic dance programs, milk added to school meals, and certain food supplements did produce improvements in some trials. The authors caution that the heterogeneity in definitions, measures, and designs across the 182 studies limits direct comparisons, and that small samples spread across a wide age range constrain strong conclusions. Their prescription for the field is twofold: more qualitative, ethnographic work to understand what executive function means within African cultural contexts before importing constructs wholesale, and locally inspired measurement tools—either adapted or newly developed and validated—so that future meta-analyses can rest on evidence that genuinely represents the continent where a billion children will grow up.

Subject of Research: Executive function research in African populations: a scoping review of definitions, methods, and findings

Article Title: What we know about executive function research in Africa: A scoping review

Article References: Ezeugwu, C., Bayley, S., & Baker, S. (2026). What we know about executive function research in Africa: A scoping review. Frontiers in Developmental Psychology, 4, Article 1885696. https://doi.org/10.3389/fdpys.2026.1885696

Image Credits: AI Generated

DOI: 10.3389/fdpys.2026.1885696

Keywords: executive function, Africa, scoping review, child development, cognitive development, working memory, inhibitory control, cognitive flexibility, cross-cultural psychology, measurement validity, low-income countries, developmental psychology

The research, conducted by Lilan Chen and Yanyan Ji of Hainan Normal University in China, compared 48 preschoolers with autism and 47 typically developing peers aged 3 to 7 years. The team assessed a broad set of numerical skills, including counting, number knowledge, and quantity transformation, alongside measures of approximate number system acuity, symbolic number comparison, verbal ability, and non-verbal reasoning. Number sense in this context refers to a cluster of early competencies that predict later mathematics achievement: knowing number words and their meanings, understanding how quantities change when objects are added or removed, and reciting and applying the counting sequence. Because mathematical difficulties are common among autistic children and often emerge early, identifying precisely where the developmental chain breaks down carries real clinical and educational weight.

The first major finding concerned the overall profile of number sense. Autistic children scored significantly lower than their typically developing peers on the composite measure, but the deficit was not uniform across all components. Their counting ability, the procedural skill of reciting number words and enumerating objects, appeared intact relative to the comparison group. What distinguished the autistic group were specific weaknesses in number knowledge, which involves grasping the meanings of number words and the cardinal quantities they denote, and in quantity transformation, the ability to reason about how small sets change under addition and subtraction. This pattern suggests that the procedural scaffolding of early numeracy can develop normally in autism even while the conceptual mapping between number words and quantities lags behind.

When the researchers turned to the approximate number system itself, they found a reassuring picture. Acuity, typically measured by asking children to judge which of two dot arrays contains more items, improved with age at a comparable rate in both groups. In other words, the non-symbolic core of numerical cognition, the perceptual system that represents quantities approximately and without language, appears to mature on a typical developmental timetable in autistic preschoolers. This finding aligns with earlier work suggesting that basic magnitude representation is largely preserved in autism, and it rules out the possibility that the observed weaknesses in number sense stem from a fundamentally impaired sense of quantity.

The surprise emerged when the team examined how approximate number acuity relates to number knowledge across the two groups. In typically developing children, the correlation between the two was robust, consistent with the long-standing view that the intuitive quantity system feeds directly into the child’s growing understanding of what number words mean. In autistic children, that correlation was significantly weaker. A sharper approximate number system did not translate as readily into better number knowledge, indicating that the usual developmental bridge between non-symbolic quantity representations and formal numerical concepts is less efficient in autism. The raw material for number learning, in other words, is present, but the channel connecting it to symbolic understanding transmits less information.

The most consequential result came from a mediation analysis, a statistical technique for testing whether the relationship between two variables operates through an intermediate factor. In the typically developing group, the pathway from approximate number acuity to number sense followed the pattern familiar from the broader literature, with symbolic skills contributing alongside the direct link. In the autism group, the picture changed qualitatively: symbolic number comparison, the speed and accuracy with which children judge which of two written or spoken numerals is larger, fully mediated the relationship between approximate number acuity and number sense. Once symbolic number comparison was accounted for, the direct association between acuity and number sense disappeared. For autistic preschoolers, the value of a precise intuitive number sense appears to be realized almost entirely through its translation into symbolic form.

This finding carries theoretical significance for debates about how mathematical cognition develops. In dominant models of numerical development, non-symbolic and symbolic representations interact bidirectionally, with approximate quantities giving meaning to number words and symbols, and symbolic practice in turn refining the intuitive system. The new results suggest that in autism this reciprocal architecture is weighted differently. Rather than non-symbolic acuity driving number sense directly, symbolic number processing acts as the necessary gateway through which approximate quantity information influences formal numerical understanding. This resonates with accounts of autism that emphasize atypical integration of perceptual and linguistic information, and it echoes prior reports that autistic children’s mathematical profiles depend heavily on verbal and symbolic mediation rather than on intuitive estimation alone.

The practical implications may prove just as important as the theoretical ones. If symbolic number comparison is the bottleneck through which approximate number knowledge reaches number sense in autistic children, then interventions that focus exclusively on training non-symbolic quantity discrimination, such as dot comparison games, may yield limited benefit unless they are paired with explicit symbolic scaffolding. The authors argue that mathematical instruction for autistic preschoolers should deliberately integrate symbolic number processing, for example by systematically mapping numerals and number words onto concrete quantities, rather than assuming that intuitive quantity experience will translate into symbolic understanding on its own. This recommendation aligns with a growing body of work showing that structured, symbol-anchored approaches benefit autistic learners across academic domains.

The study also adds nuance to the long-standing stereotype of autistic individuals as either mathematically gifted or uniformly impaired. Previous research has documented both superior mathematical abilities in some autistic children, supported by atypical but efficient brain organization, and substantial delays in others, with heterogeneity being a defining feature of the condition. By pinpointing counting as intact while number knowledge and quantity transformation lag, the new findings offer a more precise map of where early numerical development diverges in autism. They also reinforce evidence that verbal ability and non-verbal reasoning, which the researchers measured and controlled for, shape the numerical profiles of both groups, underscoring that number sense emerges from an interaction of domain-specific and domain-general capacities.

Several caveats temper the conclusions. The cross-sectional design captures developmental differences across ages but cannot establish causal direction, so it remains possible that growing number sense itself sharpens symbolic comparison rather than the reverse, or that both reflect a third influence. The sample, drawn from preschoolers in China, may not generalize to all educational and linguistic contexts, and the mediation result, while striking, is based on a moderately sized group of 48 autistic children. Longitudinal and intervention studies will be needed to confirm whether strengthening symbolic number comparison in autistic preschoolers actually accelerates the development of number sense. Even so, the study marks an important step: it identifies a specific, testable cognitive mechanism that distinguishes how autistic children build their earliest mathematical concepts, and it points educators toward a concrete target. For a population in which early academic difficulties compound over time, knowing that the intuitive number sense is intact and that the symbolic bridge is the critical link offers both a scientific insight and a practical starting point.

Subject of Research: The development of number sense and approximate number system acuity in preschoolers with autism

Article Title: Development of Number Sense in Preschoolers With Autism and its Relation to Approximate Number System Acuity

Article References: Chen, L., & Ji, Y. (2026). Development of Number Sense in Preschoolers With Autism and its Relation to Approximate Number System Acuity. Journal of Autism and Developmental Disorders. https://doi.org/10.1007/s10803-026-07567-y

Image Credits: AI Generated

DOI: 10.1007/s10803-026-07567-y

Keywords: number sense, autism, approximate number system, symbolic number comparison, preschoolers, numerical cognition, counting, number knowledge, quantity transformation, cognitive development, mathematics intervention, developmental psychology

The research team, led by Michael T. Willoughby of RTI International and Amanda C. Wylie, with collaborators spanning the University of Nairobi, Kenyatta National Hospital, the Kenya Medical Research Institute, Seattle Children’s Research Institute, and the University of Washington, drew on two prospective cohort studies. The first, Tunza Mwana, enrolled 350 mother-child dyads in rural Migori County, half of them involving children prenatally exposed to HIV; 64 children attempted the executive function assessment at their age-3 visit. The second, the ABC study, followed 400 dyads in Nairobi’s Dandora area, near the city’s main dumpsite where open waste burning is routine; 161 children attempted the same battery. Both studies used identical tablets, a common approach to assessor training, and some cross-over in assessors, making the replication unusually clean.

The battery itself, known as Tangerine EF Touch, is a tablet-based set of tasks previously used with preschool-aged children in Kenya with strong psychometric properties, including longitudinal measurement invariance, retest reliability, and criterion and predictive validity. The assessment begins with orientation tasks that make no executive function demands—children simply pop blue bubbles that appear at random positions on the screen, a measure of processing speed and engagement. Then come the real tests: inhibitory control tasks such as Animal Go/No-Go, in which children touch a button for every animal except cats; Mango-Banana, a spatial conflict task requiring children to touch the matching fruit even when it appears on the opposite side of the screen; and Silly Sounds, a Stroop-like task in which children must touch the animal that does not make the sound they hear. Working memory is probed by Pick the Picture, a self-ordered pointing task, and Animal Location, a Corsi-like visual-spatial task in a 3×3 grid. Cognitive flexibility is measured by Something’s the Same, an item selection task requiring children to match pictures on color, shape, or size.

The structure of each task follows a careful protocol. An assessor introduces the task with a standardized script, demonstrates a correct response, and then presents untimed training items—roughly two to seven, depending on the task—that make minimal executive function demands. If a child fails the training items after up to two attempts, the tablet itself, not the assessor, automatically discontinues the task. This gating mechanism is meant to ensure that test scores reflect genuine executive function skill rather than misunderstanding. In theory, only children who demonstrate comprehension proceed to the timed test items, where responses must occur within 3,000 to 4,500 milliseconds.

In practice, the gating mechanism filtered out most children. In the rural Tunza Mwana cohort, individual task completion rates ranged from 17 percent for Animal Go/No-Go and Animal Location to 66 percent for Mango-Banana and 70 percent for Pick the Picture; on average, children passed training items for only 1.7 of the 4 possible tasks. In the urban ABC cohort, completion rates ranged from 18 percent for Silly Sounds to 74 percent for Chicken-Dog, with children passing training items for an average of 2.7 of 6 tasks. The pattern was remarkably similar across the two cohorts despite substantial differences in household access to electricity, maternal education, and children’s performance on the Bayley scales of cognitive and language development.

Among children who did pass training items and proceeded to test items, accuracy was typically poor. Children who completed the Animal Go/No-Go task answered an average of 48 percent of items correctly—exactly what would be expected from a dichotomous touch-or-don’t-touch decision made at random. Performance on Mango-Banana averaged 28 to 29 percent correct, below the 50 percent chance level for a two-choice spatial conflict task. Silly Sounds yielded 33 percent accuracy, and Animal Location produced 21 to 23 percent correct responses across forward and backward conditions. Only Chicken-Dog, which uses just two stimuli—a chicken and a dog—produced above-chance performance, with 66 percent accuracy on inhibitory control items and 71 percent on sustained attention items. Pick the Picture and Something’s the Same hovered around 52 to 56 percent.

The team then tested whether well-known correlates of executive function—household socioeconomic status, caregiver education, children’s general cognitive ability on the Bayley-4, and assessor-rated attention on the Preschool Self-Regulation Assessment—predicted task completion or accuracy. The results were largely null. In the Tunza Mwana cohort, none of these predictors were significantly associated with the likelihood of completing any of the four tasks. In the ABC cohort, only 4 of 50 univariate tests reached statistical significance, most of which would not survive adjustment for multiple testing. Correlations between task accuracy and child-level or household-level characteristics were weak and inconsistent, sometimes running in counterintuitive directions—children from homes with electricity performed worse on Mango-Banana in the rural cohort, for example. These largely random patterns of completion and performance raise fundamental questions about what the task scores actually measure in this age group.

The findings echo recent warnings from high-income country studies of the NIH Toolbox executive function tasks. In a large sample of exclusively 3-year-olds, roughly 30 percent of children could not complete practice items, and among those who did, 70 to 80 percent performed at or below chance on test items. Studies of children from disadvantaged backgrounds in emergency housing and high-poverty urban school districts found that 45 to 70 percent required developmentally extended, simplified versions of the flanker and dimensional change card sort tasks. The Kenyan results extend this pattern to low- and middle-income country contexts, where children face additional risk factors—infectious disease, environmental contaminants, malnutrition—that may undermine executive function development, and where cultural assumptions embedded in task design may pose further barriers.

Why did the tasks fail? The authors point to features of task design and child experience. Tasks with higher completion rates—Mango-Banana, Pick the Picture, Chicken-Dog—had simple, explicit instructions and training items that made few attentional or working memory demands. Tasks with lower completion rates involved more complex demands or challenging language conventions: Animal Location required children to monitor a sequence of pictures in a grid, and Silly Sounds asked children to choose the opposite association, a concept of

Subject of Research: Developmental Psychology

Article Title: Using computerized measures of executive function skills in 3-year-olds—A cautionary tale from Kenya

Article References: Willoughby, M. T., Wylie, A. C., Collett, B. R., Adhiambo, J., Otieno, C., Mwangi, L., Oucho, I., Nyaguthi, P., Lihanda, P., Wanini, E. P., Magedson, A., Wamithi, S., Mutai, B. C., Tiwari, R., Maleche-Obimbo, E., Wamalwa, D., Singa, B., McGrath, C. J., & Benki-Nugent, S. (2026). Using computerized measures of executive function skills in 3-year-olds—A cautionary tale from Kenya. Frontiers in Developmental Psychology, 4, Article 1881826. https://doi.org/10.3389/fdpys.2026.1881826

Image Credits: AI Generated

DOI: 10.3389/fdpys.2026.1881826

Keywords: executive function, early childhood, tablet-based assessment, Kenya, LMIC, neurodevelopment, cognitive development, developmental psychology, computerized, measures, executive, function

The study, published in Frontiers in Developmental Psychology, is, according to its authors, the first to examine the relationship between screen exposure and psychomotor, communicative, socio-emotional, and tactile competencies in very preterm infants at 12 months corrected age. Its findings arrive amid a striking shift in the digital environments surrounding infants: television running in the background, parents’ smartphones perpetually within reach, and content that is rarely designed for babies at all.

Recruitment drew on the routine follow-up program that all very preterm survivors in the region attend after hospital discharge. Of 147 children born very preterm who survived, the researchers excluded those with major congenital malformations, severe brain injury, or parents insufficiently fluent in French to complete the questionnaires. After accounting for refusals, families lost to follow-up, and incomplete questionnaires, 64 infants entered the analysis—38 boys and 26 girls, with a mean gestational age of 28.9 weeks and a mean birth weight of just 1,162 grams. Fifty-nine percent had bronchopulmonary dysplasia, and nearly one in five had experienced neonatal sepsis, underscoring how medically fragile this cohort was from the start.

Parents completed the Family Media Use questionnaire, which catalogued the household’s electronic devices and asked them to estimate, for weekdays and weekends alike, how much time their child spent watching television or using tablets and smartphones. The answers revealed a household landscape saturated with screens: an average of seven devices per home, with parents spending nearly six hours a day on screens for work and about five hours a day for personal use. Seventy-two percent of parents reported using screens while their child was in the room, averaging one hour daily. Twenty-three percent said the television was often on in the background, and roughly one in five systematically watched television during family meals.

Direct exposure among the infants themselves was less universal but still substantial. Thirty-nine percent of the babies—25 of the 64—were directly exposed to screens, averaging about four hours per week, with individual exposure ranging from half an hour to 14 hours weekly. That figure exceeds the roughly 1.75 hours per week reported for infants under one year in earlier research, and the authors note that screen time typically climbs with age: data from the French Elfe cohort show average daily viewing rising from 52 minutes at age two to one hour and 40 minutes by age 5.5.

Each child underwent a battery of assessments during the routine follow-up consultation. Child psychologists, psychomotor therapists, and physiotherapists administered the Bayley Scales of Infant Development III, a standardized instrument measuring cognitive, language, and motor development. Parents completed the Ages and Stages Questionnaire: Social-Emotional, a screening tool covering self-regulation, compliance, autonomy, affect, and interaction with others. The team also designed experimental tasks: one tested whether the infant preferred a helpful puppet over one that withheld a ball; another observed whether the child, after watching one experimenter help another build a tower, would hand over blocks themselves; a third counted gaze alternations and pointing gestures to quantify joint attention. Finally, a tactile exploration task video-recorded each child playing with a textured plastic cube and three different toys, coding the duration of active exploration and the variety of strategies used—pressing, shaking, stroking, mouthing, rotating, throwing. Crucially, the single trained rater who coded all the videos did so before ever seeing the screen-time questionnaires, guarding against bias.

The statistical picture that emerged was nuanced. When the researchers simply compared screen-exposed infants with unexposed ones, no significant differences appeared on any Bayley scale, the social-emotional questionnaire, or any of the experimental tasks. Nor did correlations across the entire cohort reach significance. But when the analysis narrowed to the 25 directly exposed infants, a clear dose-response pattern surfaced: greater screen time correlated negatively with cognitive scores (ρ = −0.34, p = 0.048) and, more strongly, with language scores (ρ = −0.56, p = 0.002). Higher exposure also predicted fewer exploration strategies during the tactile task (ρ = −0.39, p = 0.02), an association that actually strengthened after adjustment for gestational age and socio-economic status. Notably, motor scores showed no relationship with screen time, and neither did prosocial behavior, joint attention, or the parent-rated social-emotional total.

That last null result surprised the team, given how much prior research links early screen exposure to poorer social and emotional outcomes. The authors offer several explanations. Socio-emotional skills may evolve on a different timetable and only become measurable later in development. Pointing, in particular, emerges late in preterm children—studies have shown that extremely preterm infants produce significantly fewer pointing gestures at 18 months than full-term peers, a deficit linked to later language delay—so the rarity of pointing in this 12-month sample may have limited the task’s sensitivity. Previous work has also found that gaze-based joint attention behaviors are more affected by screens than gesture-based ones, and only a subset of infants in this cohort had begun pointing at all.

The findings align with a substantial literature. A longitudinal study of 2,441 children found that heavier screen use at 24, 36, and 60 months predicted poorer performance on developmental screening questionnaires at subsequent ages. A meta-analysis of language outcomes reported negative correlations between children’s language skills and both daily screen duration and background television, and found that later first exposure was associated with better language skills. Research on the mechanisms is equally telling: when a television is on, parents speak less and infants vocalize less, eroding the dyadic exchanges on which early language depends. The displacement theory offers a complementary frame—every hour in front of a screen is an hour not spent in interactive play, physical exploration, or social engagement, experiences that are especially critical for very preterm infants whose brains are already maturing atypically.

The study also uncovered a social gradient: within the exposed subgroup, lower family socio-economic status was associated with greater screen exposure, echoing earlier findings that parents of lower socio-economic status adhere less strictly to screen-time guidelines for toddlers. The authors are careful to frame their work as a pilot. Parent-reported screen time is vulnerable to recall and social-desirability bias; the questionnaire captured quantity but not content quality, co-viewing, or background exposure; the observational design precludes causal inference; and the small, attrition-prone sample limits statistical power. Still, the message for families is concrete. The researchers argue that awareness campaigns alone are insufficient, and that parents need practical guidance—skills for reading their infant’s cues, and alternatives to screens that foster meaningful interaction from birth. For a population already navigating elevated neurodevelopmental risk, the first year may be precisely the wrong time to hand over a screen.

Subject of Research: Associations between early screen exposure and cognitive, language, socio-emotional, and tactile development in very preterm infants at 12 months corrected age

Article Title: Screen exposure and reduced cognitive abilities, language development, and tactile exploration in very preterm infants aged 12 months—A pilot study

Article References: Liverani, M. C., Lordier, L., Durand-Ruel, M., Gillioz, E., Ha-Vinh Leuchter, R., Gentaz, E., Lejeune, F., & Borradori-Tolsa, C. (2026). Screen exposure and reduced cognitive abilities, language development, and tactile exploration in very preterm infants aged 12 months—A pilot study. Frontiers in Developmental Psychology, 4, Article 1875016. https://doi.org/10.3389/fdpys.2026.1875016

Image Credits: AI Generated

DOI: 10.3389/fdpys.2026.1875016

Keywords: very preterm infants, screen exposure, cognitive development, language development, tactile exploration, Bayley Scales, joint attention, prosocial behavior, socio-economic status, infant development, pilot study, digital media

The Yucatec Maya peninsula, where the ethnographic work underlying this perspective was carried out, is home to communities where children’s daily lives unfold in close proximity to adults’ work rather than in separate child-centered spaces. From the time infants can sit upright, they are positioned within the flow of household activity, watching their mothers cook, wash, weave, and tend to younger siblings. This arrangement means that learning begins not with formal instruction but with observation, a pattern that researchers of Indigenous American communities have documented repeatedly. By the age of one, when toddlers begin to walk, they are already invited to participate in small ways, fetching an object or picking up after themselves, and these small contributions gradually expand into more substantial responsibilities as children grow. The developmental trajectory, in other words, is one of increasing integration into family work, and it is precisely within this integration that the authors locate the playful dimensions of childhood.

What distinguishes this perspective from much of the existing play literature is its insistence that the boundary between work and play, so firmly drawn in Western developmental psychology, is not a universal feature of childhood. In many middle-class North American and European households, chores are framed as obligations that compete with play for children’s time, and parents often structure the day so that responsibilities are completed before free play can begin. In the Yucatec Maya communities described here, no such sharp division exists. Children may interrupt a task to chase a chicken, turn washing clothes at the creek into an afternoon of swimming, or transform running an errand into a social adventure with siblings and friends. The task still gets done, but the emotional texture of the experience is one of enjoyment, sociability, and freedom rather than burden.

The authors’ positionality statement adds an important layer of credibility and nuance to this argument. Both researchers grew up in a Purépecha-heritage rural town and immigrated to the United States as adolescents, giving them firsthand experience of the childhoods they now study from an academic vantage point. Their recollections of fetching water, milking cows, washing dishes, and caring for babies are not remembered as drudgery but as woven into a childhood that felt expansive and joyful despite material scarcity. This dual perspective, as both participants in and observers of Indigenous childhoods, allows them to challenge deficit framings from within. When researchers from WEIRD backgrounds encounter communities with few manufactured toys and few adult-led play sessions, they sometimes conclude that children there are deprived of play. The authors’ lived experience suggests the opposite: play flourishes in forms that standard measures fail to capture.

The theoretical scaffolding for this argument draws heavily on Vygotsky’s insight that play is a culturally situated activity. Vygotsky argued that during pretend play, children create imaginary situations, take on social roles, and follow the rules attached to those roles, and that the content of these roles is supplied by the surrounding culture. He also proposed that play creates a zone of proximal development in which children can perform above their usual level, especially when supported by more knowledgeable peers. In Yucatec Maya communities, this framework takes on a distinctive shape. The roles children emulate are household and community roles, caring for infants, preparing food, tending animals, and the more knowledgeable peers are often slightly older siblings or cousins rather than adults. Play thus becomes a rehearsal space for culturally valued competence, with the content of the rehearsal drawn directly from the rhythms of family life.

The empirical basis for the perspective is substantial. The ethnographic data were collected by Alcalá across multiple visits to Yucatec Maya communities beginning in 2014, including a two-year fieldwork ethnography and a six-month stay in the fall of 2022. In the spring of 2024, semi-structured interviews were conducted with children, parents, grandparents, teachers, and community leaders. This combination of long-term participant observation with systematic interviews across generations strengthens the claim that the play-chore relationship is a stable cultural pattern rather than an artifact of a single observation period. The interviews with grandparents in particular point to the intergenerational transmission of these norms, suggesting that the symbiosis of work and play has persisted even as communities encounter schooling, media, and market economies that often promote more segregated views of childhood.

One of the most striking findings from the maternal reports is the early age at which learning is understood to begin. Yucatec mothers described sitting babies next to them while doing chores as soon as the infants could sit independently, around six months of age. This practice reflects a cultural model in which even preverbal children are legitimate participants in the social world, absorbing the sensory and emotional landscape of community life long before they can contribute labor. Infants and toddlers are permitted to experience the full range of emotions and sensory information around them, entering what the authors describe as an intricate web of social relations and responsibilities. This contrasts with developmental schedules in which infants are often sequestered in child-specific environments, and it suggests that the foundations of prosocial development are laid through ambient participation rather than deliberate teaching.

The concept of autonomy deserves particular attention. In many Indigenous communities across the Americas, children are described as having considerable freedom to manage their own daily agendas. They decide when to play, what to play, and how to balance their play with contributions to the household. This is not permissive neglect but a culturally patterned form of respect for children’s agency, rooted in the belief that children learn best when they choose to participate rather than when they are compelled. Research on learning by observation and initiative in Indigenous-heritage communities of the Americas has shown that children who are free to volunteer their help often develop keen attention to ongoing events, a quality that supports both learning and social harmony. The Yucatec Maya case fits this broader pattern: children are always present, always watching, and free to step in when a task captures their interest.

The cognitive and social benefits attributed to this arrangement are worth spelling out. Through the interweaving of chores and play, children practice cooperation with siblings and peers, negotiate the division of labor, solve practical problems such as how to carry water or care for a fussy toddler, and build reputations as responsible contributors. The authors note from their own childhoods that establishing a reputation as hard workers even opened doors to paid opportunities in the neighborhood, illustrating how early contributions translate into social standing. These are precisely the kinds of skills, self-regulation, problem-solving, language, and abstract thinking, that Vygotsky associated with play, but here they emerge through a different route: the playful performance of meaningful work rather than adult-designed play scenarios.

The critique of WEIRD-centric developmental science runs throughout the perspective and has practical implications for the field. Recent special issues on play and executive function have explicitly called for the inclusion of non-WEIRD samples to reflect the experiences of children in the Global South. The concern is not merely representational. If theories of play are built almost exclusively on settings where play is the central occupation of childhood and is often adult-structured or toy-mediated, then the alleged benefits of play may be conflated with particular cultural forms of play. As the authors argue, following earlier scholarship on play as a culturally constructed activity, the benefits of play cannot be disentangled from the unique characteristics that play takes in a given community. In Indigenous communities, those characteristics include the emulation of household chores, which means that a child pretending to cook or actually helping to cook may be engaging in functionally similar learning.

The perspective also speaks to broader debates about learning through observation versus instruction. In many school-based and laboratory-based models, learning is assumed to require verbal instruction, demonstration, or scaffolded mini-lessons framed as playful learning. The Yucatec Maya evidence suggests an alternative: children learn by being present, watching, and gradually taking initiative, with adults rarely issuing direct commands to help. This model, sometimes called learning by observing and pitching in, has been documented across Mexican Indigenous communities and elsewhere in the Americas, and it reframes what counts as a learning environment. The household itself, with its ongoing stream of purposeful activity, becomes the classroom, and the child’s voluntary participation becomes the lesson.

For educators and policymakers, the implications are significant. As Indigenous children increasingly attend formal schools that import Eurocentric assumptions about the separation of work and play, there is a risk that their home-based learning strengths will be misread as deficits, for example, when a child who attentively observes before acting is seen as passive, or when a child who contributes to family work is seen as overburdened. The authors advocate for more inclusive accounts of children’s development that recognize play as culturally situated and that value the agency, inclusion, and autonomy that characterize Indigenous childhoods. Recognizing the symbiosis of play and chores also invites a rethinking of how playful learning might be supported in classrooms serving Indigenous children, perhaps by incorporating collaborative, purposeful, and child-initiated activities rather than relying solely on adult-structured play.

Ultimately, the perspective makes a contribution that extends beyond Maya studies. By documenting how household responsibilities and play can be one and the same rather than separate activities, it widens the conceptual space of developmental psychology and challenges the field to examine whose childhoods define its theories. The ethnographic record indicates that children in Indigenous and Indigenous-heritage communities engage in play as much as children anywhere, managing their own endeavors while cleaning, running errands, helping with gardens, and contributing to their parents’ work. That this play looks different from the toy-rich, adult-organized play of WEIRD settings is not evidence of its absence but of its diversity. The authors’ call is for a developmental science capacious enough to see joy, learning, and belonging in a child washing clothes at a creek with friends, and rigorous enough to study those moments on their own cultural terms.

Subject of Research: The symbiotic relationship between play and household chores in Yucatec Maya children's learning and development

Article Title: An Indigenous perspective of the symbiotic relationship between play and household chores

Article References: Alcalá, L., & Díaz Lara, G. (2026). An Indigenous perspective of the symbiotic relationship between play and household chores. Frontiers in Developmental Psychology, 4, Article 1909412. https://doi.org/10.3389/fdpys.2026.1909412

Image Credits: AI Generated

DOI: 10.3389/fdpys.2026.1909412

Keywords: Yucatec Maya, Indigenous children, play, household chores, child development, unstructured play, cognitive development, prosocial behavior, cultural psychology, autonomy, WEIRD samples, developmental psychology

Rare earth elements are a group of seventeen chemically similar metals, including neodymium, cerium, and ytterbium, that have become indispensable to modern technology. They appear in magnets, batteries, catalysts, and electronic displays, and as mining and manufacturing have intensified worldwide, these elements have quietly accumulated in soil, water, and air. People are exposed through food, drinking water, and dust, and pregnant women pass them across the placenta to their developing babies. While previous research had hinted that prenatal exposure to these metals could impair childhood neurodevelopment, the biological mechanisms remained murky.

To probe those mechanisms, researchers turned to the Wuhan Healthy Baby Cohort, a long-running birth cohort study in central China. The team, led by Ya Xie and Wei Xia of Wuhan Children’s Hospital and Huazhong University of Science and Technology, measured concentrations of thirteen rare earth elements in urine samples collected from mothers during the first trimester of pregnancy. They then performed metabolomic profiling on cord blood, the blood remaining in the placenta after birth, capturing a snapshot of each newborn’s metabolic state. Two years later, trained assessors evaluated each child’s cognitive and motor skills using the Bayley Scales of Infant Development, a widely used standardized test.

The results were striking. After adjusting for a range of covariates, the researchers found that higher first-trimester maternal levels of seven rare earth elements were each significantly associated with increased odds of cognitive developmental delay. The elements neodymium, samarium, gadolinium, holmium, erbium, thulium, and ytterbium each carried elevated risk, with adjusted odds ratios ranging from 1.13 to 1.25 for every one-unit increase in natural log-transformed urinary concentration. In practical terms, a modest rise in maternal exposure translated into a measurable increase in the likelihood that a toddler would score below developmental benchmarks on cognitive testing.

Because people are exposed to mixtures of rare earth elements rather than single metals in isolation, the team also used two statistical approaches designed for environmental mixtures: quantile g-computation and weighted quantile sum regression. Both methods confirmed a positive overall mixture effect, meaning the combined burden of rare earth elements raised the risk of both cognitive and psychomotor developmental delays. Intriguingly, the two methods identified different dominant contributors. Ytterbium emerged as the primary driver of cognitive developmental delay, while cerium played the leading role in psychomotor delay, hinting that individual rare earth elements may exert distinct biological effects even within a chemically similar family.

The study’s most innovative move came next. Rather than treating metabolites as isolated signals, the researchers applied weighted gene co-expression network analysis, a technique originally developed for genomics, to the cord blood metabolomic data. Using a soft-thresholding power of 5, which produced a network with strong scale-free topology, the team clustered thousands of metabolites into thirteen color-coded modules representing coordinated metabolic networks. This approach allowed them to ask which entire biological pathways, rather than individual molecules, were perturbed by prenatal rare earth exposure.

Two modules stood out. Prenatal rare earth element exposure was consistently associated with perturbations in metabolic modules enriched in lysophospholipids and phosphatidylethanolamines, two classes of phospholipids that are fundamental building blocks of cell membranes. These molecules are especially important in the developing brain, where membranes are being rapidly assembled and remodeled as neurons grow and form connections. The finding suggests that rare earth elements may interfere with fetal neurodevelopment by scrambling the lipid architecture on which brain construction depends.

Crucially, the association was more than correlational. Mediation analyses demonstrated that the lysophospholipid and phosphatidylethanolamine modules partially mediated the link between prenatal exposure and increased risk of neurodevelopmental delay. In other words, part of the statistical pathway from rare earth exposure to developmental impairment runs through these disrupted lipid networks. The identification of a plausible biological mechanism elevates the findings from an observational association toward a more causal interpretation, though the researchers note that mediation captures only a portion of the overall effect and other pathways likely remain to be discovered.

The implications ripple outward in several directions. For public health officials, the study strengthens the case for including rare earth elements in routine risk assessments during pregnancy, a step that has lagged far behind their growing environmental presence. As global demand for these metals surges with the green energy transition and the proliferation of electronic devices, exposure levels in ordinary populations may continue to climb. The study also points toward potential interventions: if phospholipid disruption is a key mechanism, researchers could eventually explore whether nutritional or pharmacological strategies that support healthy lipid metabolism during pregnancy might buffer developing brains against environmental insult.

For the families in Wuhan whose participation made the study possible, the research offers no easy answers, since rare earth exposure is diffuse and difficult for individuals to avoid. But it adds an urgent data point to a larger conversation about the hidden costs of the technologies that define modern life. The metals that power our digital world are now demonstrably reaching the next generation before they take their first breath, and the developing brain appears to register their presence in ways we are only beginning to measure. As the authors conclude, the findings highlight the need for health risk assessment of rare earth element exposure during pregnancy, and they provide early clues to intervention targets that could protect children before the damage is done.

Subject of Research: Prenatal rare earth element exposure and its association with neurodevelopmental delay and phospholipid metabolic disruption in children

Article Title: Cord blood metabolic network profiles link prenatal rare earth element exposure to neurodevelopmental delay in 2-year-old children

Article References: Xie, Y., Qiu, L., Fang, X., Cao, Z., Li, S., Gong, H., Tan, T., Wang, J., Li, Y., Xu, S., Xiao, H., Zhou, A., & Xia, W. (2026). Cord blood metabolic network profiles link prenatal rare earth element exposure to neurodevelopmental delay in 2-year-old children. BMC Medicine. https://doi.org/10.1186/s12916-026-05306-9

Image Credits: AI Generated

DOI: 10.1186/s12916-026-05306-9

Keywords: rare earth elements, prenatal exposure, neurodevelopmental delay, metabolomics, cord blood, phospholipid metabolism, WGCNA, Bayley Scales, birth cohort, cognitive development, psychomotor development, environmental health

The research, led by Golia Shafiei and colleagues including Theodore Satterthwaite and Russell Shinohara, drew on two large independent neuroimaging datasets of young people: the Philadelphia Neurodevelopmental Cohort-derived HCPD sample with 565 participants and the Healthy Brain Network sample with 729 participants, all between 8 and 22 years of age. By analyzing resting-state functional MRI recordings, in which participants simply lie still while spontaneous brain activity is measured, the team estimated the intrinsic timescale of cortical regions across the entire brain in each individual.

The intrinsic timescale is extracted from the temporal autocorrelation of spontaneous neural signals, a statistical fingerprint of how slowly or rapidly a region’s activity fluctuates on its own, without any external task. Regions with short timescales behave like rapid-fire relays, discarding information quickly and responding to the immediate moment. Regions with long timescales act more like accumulators, holding onto incoming signals and integrating them over extended windows. This measure has been validated across species and imaging modalities, and it consistently reveals the same cortical hierarchy: sensorimotor cortex at the fast end and association cortex at the slow end.

What the new study adds is the developmental dimension. When the researchers mapped how intrinsic timescales change with age across the two youth cohorts, they found that maturation did not proceed uniformly across the cortex. Instead, developmental changes were organized along what neuroscientists call the sensorimotor-association axis, a fundamental gradient of cortical organization that stretches from primary sensory and motor areas at one pole to higher-order association regions such as the prefrontal and parietal cortex at the other. The developmental patterns in timescale recapitulated this axis with striking fidelity.

In practical terms, this means that the brain’s temporal architecture matures hierarchically. The fastest, most concrete processing systems in sensorimotor cortex reach their mature timescale profiles earlier, while the protracted remodeling of temporal windows continues longest in association cortex, the regions responsible for the most abstract and integrative cognitive functions. This mirrors a well-established principle of brain development, in which evolutionarily older, primary systems consolidate early and phylogenetically newer, higher-order systems mature last, sometimes not until the third decade of life.

A critical strength of the study lies in its replication strategy. Developmental neuroimaging is notoriously vulnerable to sample-specific artifacts, scanner differences, and motion confounds, so findings from a single cohort often fail to generalize. By requiring that the developmental pattern appear consistently in both the HCPD and HBN samples, which were collected with different protocols at different sites, the authors substantially raised the evidentiary bar. The convergence across these two independent youth datasets indicates that the hierarchical maturation of intrinsic timescale is a robust biological phenomenon rather than a statistical fluke of one dataset.

To test whether the observed changes were genuinely developmental rather than a general property of brain organization at any age, the team turned to a third dataset: the Human Connectome Project young adult sample, comprising 973 healthy adults between 22 and 37 years old. The analysis of this adult cohort underscored the specificity of the youth findings. While the canonical sensorimotor-to-association hierarchy of timescales is clearly present in adults, the age-related developmental gradients along that axis seen in children and adolescents were not present in adulthood. In other words, the hierarchical sculpting of temporal windows is an active process of youth, and by the early twenties it has largely stabilized.

This stabilization carries conceptual weight for developmental neuroscience. The adult cortex maintains its hierarchical timescale organization, with short windows in sensorimotor areas and long windows in association areas, but that organization functions as a fixed scaffold rather than a moving target. The youth data reveal the period during which that scaffold is actively constructed. The findings therefore suggest a convergence between two major descriptive frameworks of cortical organization: the intrinsic timescale hierarchy documented across species and modalities, and the sensorimotor-association axis that has emerged as a unifying principle of cortical variation and development. The same geometric axis along which cortical properties vary appears to be the axis along which the brain’s temporal dynamics mature.

The implications extend beyond basic science. Intrinsic timescale is increasingly studied as a marker of neural computation, and atypical development of temporal processing windows has been implicated in neurodevelopmental conditions characterized by differences in cortical maturation. Establishing a normative, replicated developmental trajectory for this measure in more than 1,200 young people provides a principled reference against which deviations can be measured. Because the measure is derived from widely available resting-state fMRI, it could eventually serve as a noninvasive index of hierarchical brain maturation, complementing structural measures such as cortical thickness and myelination that follow similar sensorimotor-to-association developmental gradients.

The study also highlights the value of large-scale, multi-cohort collaboration in developmental science. With authors spanning institutions and datasets including the Human Connectome Project development and young adult phases and the Healthy Brain Network, the work exemplifies a shift toward reproducible, population-scale characterization of the developing brain. The picture that emerges is one of elegant temporal choreography: the brain builds its hierarchy of processing windows from the bottom of the sensorimotor-association axis upward during youth, and once the architecture is complete, it holds steady, providing the stable temporal foundation on which adult cognition operates.

Subject of Research: Developmental maturation of intrinsic neural timescales along the sensorimotor-association cortical axis in youth

Article Title: Intrinsic timescale develops hierarchically from sensorimotor to association cortex in youth and stabilizes in adulthood

Article References: Shafiei, G., Bagautdinova, J., Sydnor, V. J., Bassett, D. S., Barch, D. M., Cieslak, M., Fan, Y., Flook, E., Franco, A. R., Kiar, G., Luo, A. C., Milham, M. P., Parkes, L., Salo, T., Somerville, L. H., Tong, T. T., Shinohara, R. T., & Satterthwaite, T. D. (2026). Intrinsic timescale develops hierarchically from sensorimotor to association cortex in youth and stabilizes in adulthood. PLOS Biology, 24(9), e3004037. https://doi.org/10.1371/journal.pbio.3004037

Image Credits: AI Generated

DOI: 10.1371/journal.pbio.3004037

Keywords: intrinsic timescale, brain development, cortex, sensorimotor-association axis, resting-state fMRI, adolescence, neuroimaging, hierarchical maturation, association cortex, PLOS Biology, autocorrelation, prefrontal cortex

The study drew on the Spanish Environment and Childhood (INMA) project, a population-based birth cohort established between 2003 and 2008 across four regions of Spain: Asturias, Gipuzkoa in the Basque Country, Sabadell in Catalonia, and Valencia. From 2,644 eligible women recruited during first-trimester prenatal visits, the researchers measured omega-3 fatty acid proportions in the cord plasma of 953 newborns, ultimately analysing data from 716 mother-child pairs who had at least one valid cognitive assessment during follow-up. Cord blood is a powerful biomarker because it reflects maternal diet and fatty acid transfer to the foetus during the third trimester, a critical window characterised by the rapid foetal brain growth spurt and the highest rate of polyunsaturated fatty acid accretion in development.

The team focused on three omega-3 fatty acids with distinct biological roles. Docosahexaenoic acid, or DHA, is the most abundant omega-3 in the brain and serves as the primary structural component of neuronal membranes, supporting synaptogenesis, membrane fluidity, signal transduction, and myelination, particularly in the prefrontal cortex. Eicosapentaenoic acid, or EPA, protects brain health mainly by reducing neuroinflammation and facilitating placental DHA transport. Alpha-linolenic acid, or ALA, is an essential fatty acid that mammals cannot synthesise de novo and which provides direct neuroprotection while supporting neuronal growth and plasticity. Because the human conversion of ALA to DHA is marginal and to EPA inefficient, direct dietary intake of these compounds during pregnancy is necessary.

Cognitive function was assessed repeatedly using internationally validated computer-based neuropsychological tests. Inattentiveness was measured at approximately ages 5, 7, and 11 using the Conners’ Kiddie Continuous Performance Test and the Attention Network Test, with higher values of hit reaction time standard error indicating greater inattentiveness. Working memory was evaluated at ages 7, 11, and 15 with the N-back task, using detectability in the demanding 3-back condition as the primary outcome. Fluid intelligence was assessed at around ages 9 and 15 with Raven’s Progressive Matrices and a Spanish adaptation of the Test of Primary Mental Abilities. All scores were converted to age-specific z-scores to allow comparison across different instruments and follow-up waves.

The statistical approach was what set this study apart from most previous nutritional epidemiology. Rather than comparing cognitive test results at isolated time points, the researchers used linear mixed-effects models with interaction terms between child age and fatty acid exposure, allowing them to model entire developmental trajectories from age 5 to 15. Models included cohort-level and individual-level random effects, and were adjusted for child sex, maternal age, maternal education, preconception body mass index, Mediterranean diet adherence, and alcohol consumption during pregnancy. Confounders were selected using a directed acyclic graph, and missing covariate data were handled through multiple imputation.

The results revealed a striking divergence between ALA and DHA. In overall models averaging across the whole follow-up period, higher cord plasma proportions of both ALA and DHA were associated with lower inattentiveness, and higher DHA was linked to better working memory. But the trajectory models told a more nuanced story. Children with higher prenatal ALA exposure showed significant early advantages in attention and fluid intelligence, with predicted differences between high and low exposure groups reaching 0.76 standard deviations for fluid intelligence at age 5. Yet these advantages attenuated and even reversed over time: by age 15, children with higher ALA showed slightly worse fluid intelligence scores than their lower-exposure peers, as children with lower prenatal ALA appeared to catch up and overtake them.

DHA displayed the opposite temporal pattern. Children with higher cord plasma DHA began with markedly better working memory in early childhood, with a predicted advantage of 0.54 standard deviations at age 5, but this gap gradually converged as lower-exposure children improved. Meanwhile, the benefits of DHA for attention and fluid intelligence emerged later and grew steadily stronger: children with higher DHA showed progressively less inattentiveness from age 7 onward, with the predicted difference widening to 0.67 standard deviations by age 15, and better fluid intelligence emerging by adolescence. EPA, present at very low relative abundance in cord plasma, showed no significant associations with any cognitive outcome.

The authors propose biological explanations for these divergent patterns. ALA’s early boost may reflect its influence on neuronal membrane fluidity, gene expression, and synaptic plasticity during the period when neural networks are rapidly expanding, with its effects later swamped by the growing influence of children’s own diets and postnatal environments. DHA, by contrast, is directly incorporated into neuronal membranes of the prefrontal cortex, a region that begins functioning in early childhood but continues structural refinement through adolescence. A stable structural foundation laid down during gestation could therefore support the progressive maturation of attentional control and executive networks, producing advantages that become increasingly evident as higher-order cognitive functions consolidate. The early working memory advantage of DHA is consistent with the heavy reliance of that function on the dorsolateral prefrontal cortex, a region characterised by rapid DHA accretion during late gestation.

The study’s robustness was tested extensively. Results remained virtually identical across sensitivity analyses adjusting for postnatal fish and nut intake, breastfeeding duration, maternal verbal IQ, mercury exposure, and smoking during pregnancy. Applying inverse probability weighting to account for attrition bias produced consistent trajectories and even strengthened some associations, including a progressive longitudinal gain in working memory for the highest ALA group that reached statistical significance after additional adjustment. Findings also survived false discovery rate correction. The researchers acknowledge limitations, however: cord plasma fatty acids were expressed as relative percentages rather than absolute concentrations, cord levels reflect exposure near delivery rather than cumulative intake across pregnancy, and the observational design cannot establish strict causality, even though the use of an objective prenatal biomarker preceding outcomes by more than a decade establishes clear temporality.

The implications reach beyond academic interest. The findings underscore the importance of distinguishing between individual omega-3 fatty acids when evaluating their role in neurodevelopment, rather than treating omega-3 as a single nutritional category, and they highlight the need for long-term follow-up to capture cognitive associations that may be delayed by years. For pregnant women and clinicians, the study adds to existing evidence that maternal nutrition during the third trimester, when the foetal brain undergoes its most intense period of fatty acid accumulation, may have consequences that unfold across an entire decade of cognitive development. The authors call for replication in diverse populations, integration of postnatal biomarker data to disentangle prenatal from postnatal influences, and neuroimaging studies to identify the brain structural and functional mediators underlying these distinct temporal trajectories.

Subject of Research: Associations between prenatal omega-3 fatty acid exposure measured in cord plasma and longitudinal cognitive development in children

Article Title: Omega-3 cord plasma proportions and cognitive function trajectories from 5 to 15 years of age: a population-based cohort study

Article References: Pinar-Martí, A., Ayala-Aldana, N., Bernardo-Castro, S., Manidis, A., Cadman, T., Sala-Vila, A., Lázaro, I., Lertxundi, N., Subiza-Pérez, M., González-Safont, L., Vioque, J., Riaño-Galán, I., Rodríguez-Dehli, C., López-Sabater, M. C., Vrijheid, M., Guxens, M., Foraster, M., & Julvez, J. (2026). Omega-3 cord plasma proportions and cognitive function trajectories from 5 to 15 years of age: a population-based cohort study. European Journal of Epidemiology. https://doi.org/10.1007/s10654-026-01461-8

Image Credits: AI Generated

DOI: 10.1007/s10654-026-01461-8

Keywords: omega-3 fatty acids, DHA, ALA, prenatal nutrition, cognitive development, neurodevelopment, working memory, attention, fluid intelligence, birth cohort, cord blood, childhood adolescence