The effect of class and collection labels on cardinality, class-inclusion, and number conservation tasks.

3 experiments were carried out to assess Markman's hypothesis that the organizational principles underlying collection concepts facilitate children's performance on cognitive tasks requiring part-whole comparisons. In Experiment 1, the effect of class/collection labels on both cardinality and class-inclusion tasks was assessed. 32 3- and 4-year-olds from 2 populations (suburban middle class and inner-city working class) received both tasks. An additional 32 kindergarten and first-grade children from the 2 populations received the class-inclusion task. For cardinality, there was no difference in performance as a function of label. A facilitative effect of the collection label was found for class inclusion. Experiment 2 assessed the effect of class/collection labels on 28 nursery school children's demonstration of number conservation. Experiment 3 extended the age range and examined the effect of label on 56 kindergartners' and first graders' performance on number conservation. Both experiments failed to replicate Markman's findings. The results of the 3 experiments indicate that the facilitative effect of collection labels appears to be specific to the class-inclusion task. In light of these failures to replicate and the considerable variation in cognitive level among preschoolers, it is suggested that Markman's findings of a facilitative effect of collection labels on conservation and cardinality problems may have resulted from the use of small sample sizes and between-subject designs.