Autistic Preschoolers Show a Distinct Route to Number Sense, Study Finds

Long before children learn arithmetic at school, they rely on an intuitive sense of quantity that researchers call the approximate number system. This evolutionarily ancient system allows even infants and many animals to distinguish, for example, a group of eight dots from a group of twelve without counting, and its precision, known as acuity, sharpens steadily through childhood. For decades, cognitive scientists have treated this non-symbolic system as a likely foundation for formal mathematics, and studies in typically developing children have repeatedly linked sharper approximate number acuity to better math achievement in school. A new study of preschoolers with autism, published in the Journal of Autism and Developmental Disorders, now shows that this well-established pathway looks strikingly different in autistic children, and that symbolic number processing plays a far more decisive role in how their numerical abilities take shape.

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