The approximate number sense is (little more than) spatial skills

When processing non-symbolic quantities, both numerical information (processed through the Approximate Number System; ANS) and spatial information (e.g., size, density) are simultaneously processed. While the connection between ANS tasks and spatial skills has been explored at the task level, construct-level links between the ANS and spatial remain underexplored. The aim of this study is to tease apart the structure of ANS measures and spatial skills measures in early childhood through factor analyses and investigate the correlation between both constructs through testing the age and ability differentiation hypothesis. Using factor modelling, we find the ANS and spatial skills to represent the same underlying concept. This unidimensionality is further supported by the lack of any age or ability differentiation. We conclude that ANS and spatial skills seem to be inherently challenging to distinguish due to their intertwined nature. • The ANS and spatial skills are not distinct in young children. • The ANS and spatial skills capture the same underlying construct. • There is no age or ability differentiation between the ANS and spatial skills.