Spatial and Numerical Abilities in Infants and Toddlers

Abstract: Having a basic understanding of numbers and math is important for functioning in society. The first mathematical challenge children meet is to learn to understand the natural numbers (the positive integers 1, 2 ,3…). Children must learn what number words symbolize and how to use counting to determine the number of elements in a set. When children have mastered this, they are said to have a concept of natural, or symbolic number. But even before children start learning about symbolic number and other math concepts, they have spontaneously developing intuitions about geometric relations and magnitudes, what I refer to as intuitive spatial and numerical abilities. In this thesis I focus on two such abilities: being able to represent numerical magnitudes approximately without counting (numerosity perception) and sensitivity to object shape and geometric relations (visual form perception). These abilities have been found already in infancy and may provide part of the foundation for children’s later mathematical ability, as predictive relations between individual differences in these abilities and mathematical achievement have been documented. But what shapes the development of intuitive spatial and numerical abilities? According to an influential theoretical perspective, intuitive spatial and numerical abilities stem from evolutionary ancient core knowledge systems. The Core Knowledge perspective holds that these abilities are essentially innate and fully functional from birth. Alternative theoretical perspectives instead emphasize the importance of experiences, specifically sensorimotor experiences for the development of perceptual and cognitive abilities. In study I and II of this thesis we tested if sensorimotor experiences in infancy can influence the development of two aspects of infants intuitive spatial and numerical abilities: visual form and numerosity perception. In study III we turned to children’s emerging understanding of symbolic number. Theoretical accounts posit that children draw upon certain core knowledge systems and experience with language when constructing a concept of symbolic number. However, past research has mainly focused on the later stages of children’s learning about symbolic number. We instead ask: which abilities do children draw upon in the earliest stages of symbolic number learning, when they are just beginning to map out the meaning of the first number words? Across the three studies in this thesis we find that sensorimotor experiences can affect the development of visual form perception in infancy, but we find no evidence that numerosity perception is affected, and that children may draw on their experience and knowledge of language and their visuospatial working memory when beginning to learn symbolic number. The findings imply that by supporting children in their motor and language development and by providing them ample opportunities for exploration, we can set children on a path towards more successful engagement in mathematics and other STEM subjects.