Neurocognitive Architectures and the Nonsymbolic Foundations of Fractions Understanding
Children and adults experience pervasive difficulties understanding symbolic fractions. These difficulties have led some to propose that components of the human neurocognitive architecture, especially systems like the approximate number system (ANS), are ill-suited for learning fraction concepts. However, recent research in developmental psychology and neuroscience has revealed neurocognitive architectures—a “ratio processing system” (RPS)—tuned to the holistic magnitudes of nonsymbolic ratios that may be ideally suited for grounding fraction learning. We review this evidence alongside our own recent behavioral and brain imaging work demonstrating that nonsymbolic ratio perception is related to understanding fractions. We argue that this nonsymbolic RPS supports symbolic fraction understanding, similar to how the ANS supports whole-number understanding. We then outline a number of open questions about the RPS and the ways in which it may be used to support fractions learning.