The Development of the Approximate Number System in Humans and Monkeys

PROJECT SUMMARY Cognitive impairments in mathematics affect 3-6% of children in the United States. These impairments often involve one of the earliest emerging and foundational number abilities, the Approximate Number System. The Approximate Number System allows young children to tell more from fewer items and is thought to be crucial to the development of early mathematics abilities, such as learning the meaning of number words. However, we do not currently know the factors that contribute to the development of the Approximate Number System. The proposed research will increase our understanding of typical development of this system and has the potential to inform best early educational practices to help this system develop, aid in the early diagnosis of mathematic learning disabilities affecting this system, and provide an empirical basis for the development of targeted interventions. Here, we propose to measure the role of neural maturation, experience, and genetics on the development of the Approximate Number System through a combination of child development methods, comparative developmental methods with infant primates, and computational methods to evaluate a wide range of alternative hypotheses. We will use simple number estimation tasks and computerized training tasks that can be implemented in a wide range of ages and cross-species. This allows us to compare the developmental progression across two different models and test for differences due to neural maturation rate (monkeys have much more rapid neural development compared to humans). Using developmental methods in primates, we can isolate and test individual factors that contribute to this system in ways that have not been possible before, including testing the role of genetic influences (using detailed pedigree information from the primate colony) and measuring the role of experience in tightly controlled rearing environments. The proposed research thus stands to break substantial new ground in the methods that are used to study child development and has unique ways to test the assumptions from many influential developmental theories about the relative role of genetics, maturation, and experience in cognitive development. Insights about the role of these factors in early number development will have implications for our understanding of learning and development more broadly.