We studied the acquisition of the ordinal meaning of number words and examined its development relative to the acquisition of the cardinal meaning. Three groups of 3-, 4-, and 5-year-old children were tested in two tasks requiring the use of number words in both cardinal and ordinal contexts. Understanding of the counting principles was also…

Proposes the hypothesis that preschoolers have number concepts based on the numbers 1-5 rather than on the decimal structure. Results suggest that children understand numbers to 5 as a privileged anchor. Proposes a new model for a representational system of numbers. (Author/DR)

Three- to 7-year-old children were trained through reinforcement to select the more or less numerous of two rows of squares. All children successfully judged relative numerosity when number covaried with length or density, but only concrete operational children were successful when numbers did not covary with other dimensions. (Author/DB)

The "magic" paradigm was devised to assess conservation of number in young children. Subjects were 32 three- to four-year-old children. (MP)

Examines the prediction that the ordinal property of natural number symbols is more easily learned by preschoolers than the cardinal property of natural number symbols. (Author/ED)

Understanding of the cardinality principle in children with Williams Syndrome (WS) was compared to that of typically developing children. Findings indicated that such understanding was extremely delayed in WS children and only at the level predicted by their visuo-spatial mental age. Findings suggested that visuo-spatial ability played a greater…

Studies five-year-olds' relative number judgements of small and large number displays with and without perceptual aids. Children were found to respond to local rather than global density differences and to benefit from the provision of perceptual aids on both small and large number displays. (Author/AS)

Showed that in a task requiring judgments about the concept of "more" based on the relative numerosity of sets, three- to four-year-old children may base their judgments on such parameters as the extent to which the sets are homogeneous with respect to the color of their components. (Author/DB)