Short term memory is famously limited in capacity to Miller's (1956) magic number 7 plus or minus 2--or, in many more recent studies, about 4 plus or minus 1 "chunks" of information. But the definition of "chunk" in this context has never been clear, referring only to a set of items that are treated collectively as a single unit. We propose a new…

Examined the nature of numerical knowledge in 5-month-olds to inform the debate whether numerical abilities result from capacities dedicated to numerical cognition or to more general perceptual capacities. Found that 5-month-olds could determine the number of collective entities, moving groups of items, when non-numerical perceptual factors such…

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…