Quantitative competencies in infancy.

We review recently published papers that have contributed to our understanding of how the preverbal infant represents number, area and time. We review evidence that infants rely on two distinct systems to represent number nonverbally and highlight the similarities in the ratio-dependent discrimination of number, time and area. Contrary to earlier assertions that continuous dimensions are more salient (and thus more discriminable) to the infant than numerosity, we argue that the opposite conclusion is better supported by the data. The preverbal infant may be better able to extract numerosity than continuous variables from arrays of discrete items.