| Abstract: | Collections (e.g., forest, army) and classes (e.g., trees, soldiers) are natural concepts that differ in their organizational principles. Collections are organized into part-whole relations (e.g., trees are parts of a forest). Classes are organized according to class inclusion relations (e.g., oaks are kinds of trees). Because of their part-whole organization, collections are assumed to have greater psychological coherence than classes and therefore an advantage on tasks that require thinking about an aggregate as well as the individuals in it. Number requires aggregate analysis since it is a characteristic of sets, not of individuals. Four studies tested the hypothesized collection advantage in numerical reasoning tasks. In each, children viewed identical displays that were labeled with either class or collection terms. With perceptual input constant, the collection labels in contrast to the class labels promoted children's insight into certain numerical principles and facilitated the use of these principles in a variety of numerical tasks. Collection labels appear to induce a cognitive reorganization of importance to the child: the shift from inclusion to part-whole relations. |
