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

The approximate number system (ANS) is considered a foundational precursor for the development of formal mathematical abilities, which are often delayed in autistic children. However, the developmental pathways linking this non-symbolic core system to early number sense in autism remain unclear, particularly the role of symbolic number processing.

Forty-eight preschoolers with autism and 47 typically developing (TD) peers, aged 3-7 years, were assessed on number sense (including counting, number knowledge, and quantity transformation), ANS acuity, symbolic number comparison, verbal ability, and non-verbal reasoning.

Autistic children demonstrated significantly lower overall number sense, driven by specific weaknesses in number knowledge and quantity transformation, despite intact counting ability. While ANS acuity showed comparable age-related growth in both groups, its correlation with number knowledge was significantly weaker in autistic children. Crucially, and in contrast to TD children, symbolic number comparison fully mediated the relationship between ANS acuity and number sense in the autism group.

These findings suggest a distinct cognitive pattern for numerical abilities in autism, wherein the translation of non-symbolic numerical representations into formal number sense is strongly associated with symbolic number processing. This underscores the necessity of integrating symbolic scaffolding into mathematical interventions for autistic children.