Number symbols in the brain and mind

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Numbers play a critical role in many everyday life situations. From balancing the company budget to checking the scoreboard during a playoff game, numbers are constantly informing our decisions and behaviours. Over the course of cultural history, humans have invented various symbolic forms to represent numbers, ranging from prehistoric cave markings to Roman numerals. Today, Arabic numerals are the most pervasive form of symbolic number representations. Over the course of learning and development, every child has to construct neural representations to support the fluent processing of Arabic numerals. ******The central focus of my NSERC-funded research program is to better understand how our brains come to process numerical symbols, such as Arabic numerals, over the course of learning and development. Over the past 5 years my research team and I have focussed on better understanding how Arabic numerals become referents for quantity (e.g. how children learn that the symbol 5' is a representation for all sets of five objects). However, in addition to being representations of quantity, Arabic numerals convey ordinal information (e.g. 5 comes before 6 but after 4). Furthermore, Arabic numerals are shapes that form a visual category and may, therefore, be processed differently from other visual categories such as letters and faces. Presently very little is known about the ordinal and visual processing of Arabic numerals. ******In the next 5 years we will extend our understanding of the neurocognitive basis of symbolic number processing by expanding our research program beyond the study of symbols as referents for quantity. Specifically, in the proposed Project Stream A, we will investigate how the brain represents numerical order and how it is both similar to and different from neural processing of Arabic numerals as referents for quantity. Furthermore, we will study how brain representations of numerical order change over the course of development. The aim of Project Stream B is to investigate the existence of a Number Form Area (NFA) in the ventral visual cortex that underpins the visual representation of Arabic Numerals. To do so, we will study both children and adults in an effort to better understand a.) whether there exists a category-specific representation of Arabic numerals in visual areas of the brain and b.) how such a brain region becomes specialized as a function of development and experience. ******Together, these projects will significantly further our understanding of how the human brain come to process multiple referents of Arabic numerals over the course of learning and development. The proposed studies will move our understanding beyond solely studying Arabic numerals as representations of quantity towards a richer understanding of how brain circuits are specialized for the processing of the ordinal information conveyed by Arabic numerals as well as how these symbols are processed visually in the brain.