Grant: Discovery Grants Program - Individual

Whether you are counting the days until an event, calculating a tip, or estimating how many layers you need to stay warm, understanding numbers is an essential life skill. Basic number skills set the foundation for how the mind accomplishes the distinctly human task of complex mathematics. My research program combines behavioural and neuroimaging methods to study the cognitive and neural systems that form the foundation of mathematical thinking in human adults and children. Humans have a unique ability to represent numbers nonsymbolically, as an array of objects, and symbolically (e.g., '3' or 'three'). The dominant assumption in the field of numerical cognition has long been that symbolic and nonsymbolic numbers are processed using a single evolutionarily ancient abstract number processing system. My research, along with the work of others, conflicts with this assumption, instead demonstrating that symbolic and nonsymbolic numbers are processed by distinct systems, in human adults. Yet, to learn the meaning of number symbols, young children must connect symbols with the quantities they represent. This raises the intriguing question of how the symbolic and nonsymbolic number systems develop and evolve during childhood. I predict that following a brief developmental window of overlap between symbolic and nonsymbolic number systems, these systems will become independent. To test this hypothesis, I will conduct a series of longitudinal studies in children aged 5 to 9 years. These studies will employ behavioural and neuroimaging techniques to investigate how children process symbolic and nonsymbolic numbers across multiple tasks with varying attentional demands. A major milestone for young children's symbolic numerical understanding is the acquisition of verbal number knowledge (e.g., learning that the word `three' represents three items). There is a link between children's knowledge of verbal number words and their natural inclination to attend to quantities. While it has been long assumed children learn verbal number words by mapping them onto pre-existing representations of nonsymbolic quantities, recent theories have suggested that learning number words may serve as an attentional scaffold for noticing nonsymbolic quantities. I will use a longitudinal approach to uncover whether the degree to which children spontaneously pay attention to quantities is a cause or a consequence of children's acquisition of verbal number knowledge. By carefully controlling for attention-related factors, the studies in this proposal will shed light on how early numerical systems emerge and relate to each other across development. The resulting data may have important implications for how cultural inputs differentially affect developing brains.