Theoretical models of developmental dyscalculia

In recent decades, various theoretical models have been proposed to explain the origins of developmental dyscalculia (DD). In this chapter, we review domain-general and domain-specific deficit theories of DD. When considering domain-general deficits, it has been observed that verbal working memory (WM) consistently predicts differences between children with DD and typically developing children in diverse age groups and samples, even after accounting for demographic and other cognitive variables. Visual WM and central executive functions have also been shown to be impaired in children with DD. The relations between DD and the above domain-general factors depend on age and covariates considered. Regarding the three dominant domain-specific deficit theories of DD—the approximate number system deficit theory, the numerosity coding deficit theory, and the access deficit theory—the access deficit theory has received the most empirical support. Additionally, children with DD have also been found to struggle with other domain-specific skills, such as number line, counting, and conceptual knowledge. However, more studies are needed to examine the unique contribution of these skills to DD. Finally, research on potential subtypes of DD is still in its early stages. Identified DD subtypes in the literature vary depending on the deficit theories tested, the variables examined, and the classification methods used. This chapter summarizes the challenges in this research field and suggests directions for future research.