The role of unbounded number line estimation in the association between spatial skills and mathematical proficiency [Author Accepted Manuscript]

Spatial skills are robustly associated with mathematical performance, yet the cognitive mechanisms underlying this relationship in adults remain poorly understood. The present research examined whether unbounded number line estimation mediates the association between spatial skills and mathematical performance in adults. Ninety (90) undergraduate students completed measures of spatial visualization, mental rotation, algebra, fractions, arithmetic, and unbounded number line estimation. Results indicated that spatial skills significantly predicted mathematical performance and that unbounded number line estimation indirectly mediated this relationship across all three mathematical domains. These findings extend spatial representation theory to adulthood, suggesting that stronger spatial skills may support the construction of more precise internal representations of numerical magnitude, which in turn facilitate mathematical proficiency.