Developmental dyscalculia is a learning disability that affects the acquisition of knowledge about numbers and arithmetic. It is widely assumed that numeracy is rooted on the "number sense", a core ability to grasp numerical quantities that humans share with other animals and deploy spontaneously at birth. To probe the links between number sense…

Examined analog number representations in 5- to 7- year-olds. Found that subjects accurately estimated rapidly presented groups of 5 to 11 items. Children's data were qualitatively and to some degree quantitatively similar to adult data, with one exception. The ratio of the standard deviation of estimates to mean estimates decreased with age.…

Two experiments examined development of the ordinality concept in infants. Found that 11-month-olds successfully discriminated, whereas 9-month-olds failed to discriminate sequences that descended in numerical value from sequences increasing in numerical value. Nine-month-olds could discriminate the ordinal direction of sequences that varied in…