The development of area discrimination and its implications for number representation in infancy.

This paper investigates the ability of infants to attend to continuous stimulus variables and how this capacity relates to the representation of number. We examined the change in area needed by 6-month-old infants to detect a difference in the size of a single element (Elmo face). Infants successfully discriminated a 1:4, 1:3 and 1:2 change in the area of the Elmo face but failed to discriminate a 2:3 change. In addition, the novelty preference was linearly related to the ratio difference between the novel and familiar area. Results suggest that Weber's Law holds for area discriminations in infancy and also reveal that at 6 months of age infants are equally sensitive to number, time and area.