Neurocognitive Foundations of Child and Adult Number Processing : Neural Correlates and Functional Circuits Across Typical Development

Sammanfattning: The ability to mentally represent the exact numerosity of up to four perceived objects, as well as approximately estimating differences in numerical magnitude, appears to constitute a core-cognitive number sense. Symbolic representations of number (e.g., “two” and “2”) have been argued to gain meaning through a mapping against the analog nonsymbolic numerical magnitude representation (e.g., ••). Alternatively, symbolic number processing abilities may develop independently of nonsymbolic numerical cognition, instead dependent on learning the order and content of the verbal count-list (i.e., 1, 2, 3, …). This thesis aimed to determine which of these proposals best correspond to the brain’s processing of numerical information, with implications for the development of mathematics curricula.Four neuroimaging studies provide biomarkers for typical numerical cognition. Results indicate that symbolic numbers increasingly acquire semantic reference from other symbols; nonsymbolic quantities are processed in an asemantic visuospatial manner; neural correlates reach adult-level maturity at 11 years of age; numerical order and magnitude recruit independent mechanisms; and that maturation of executive functions and lexico-semantics is key for symbolic number processing. These results support the view of increasingly independent mechanisms for symbolic and nonsymbolic numerical cognition across development.