Predicting Age of Becoming a Cardinal Principle Knower

Children's first mathematics concept is their understanding of the quantities represented by number words (cardinal value), and the age at which they achieve this insight predicts their readiness for mathematics learning in school. We provide the first exploration of the factors that influence the age of becoming a cardinal principle knower (CPK), with a longitudinal study of 197 (94 boys) children from the beginning to the end of two years of preschool. Core symbolic and nonsymbolic quantitative competencies at the beginning of preschool, as well as measures of intelligence, executive function, preliteracy skills, and parental education, were used to predict timing of CPK status. Children who achieved early CPK status had higher IQ scores, knew more count words and numerals, and had a better intuitive understanding of relative quantity than their peers. Children who were delayed CPKs, in contrast, had deficits in executive function and poor preliteracy skills. The results add to our understanding of children's conceptual development in mathematics and have implications for the identification of at-risk children and design of interventions for them. Educational Impact and Implications Statement The study identifies the factors that influence the age at which children learn their first mathematics concept, the quantities represented by number words (cardinal value). Age of acquisition is related to domain-general abilities, such as executive function, and knowledge of the count list ("one, two, three . . .") and the ability to correctly enumerate collections of objects. The results have implications for the identification of and development of interventions for preschoolers at risk for long-term mathematics difficulties.