THIS DISSERTATION HAS BEEN MICROFILMED EXACTLY AS RECEIVED DEVELOPMENT OF THE CONCEPT OF CLASS IN CHILDREN DISSERTATION

substages for stage II. It is the belief of the present author, however, that most of the variance (assum­ ing a uniform method of presentation) can be accounted for by the degree of familiarity of the subject with the material. Partial support for this view comes from Bousfield and Cohen (1956) who found that there is higher recall for both males and females for words representing interests of their own sex. A limitation of the present study was that the age range of children studied comprised mainly stage II children. It is hoped that future research on the evolution of classification in children would expand the age ranges of subjects studied, thus allowing for greater generalizability of results. The present study used only girls as subjects. It would be interesting to check for possible sex effects in a future study of the development of classificatory skills in children. It would also be interesting to see if the present results are replicable with other concrete and abstract tasks. Again, this would allow for more generalizability of findings, and also lend more evidence for the postulated two substages within stage II. SUMMARY In the present study, sixty kindergarten, first, and second grade girls were presented with three tasks repre­ sentative of either concrete classification, abstract classification, or class inclusion. The first two tasks require that the child have the ability to categorize by the intensive property of objects, which is the ability to distinguish similarity and differences between objects The third task requires that a child not only be able to handle the intensive property of classes, but that he be able to coordinate this property with the extensive property of classes, which is the ability to distinguish the actual members as defined by the intensive property. The distinction between the first two classes was that for the first (sort) task, intension on a concrete level was required, whereas for the second (concept-shift) task intension on an abstract level was required. Findings showed that there was a developmental trend from concrete intensive classification to abstract intensive classifies tion to class inclusion. This trend followed an invariant order which lends support to Piaget's stage-theory of classificatory development. Considering the age of transition between 60 61 stages, the results are more ambiguous. Kindergarteners did perform at a significantly lower level than either first or second graders. It appears that kindergarteners are just entering the second stage in classificatory dev­ elopment. Thus, the finding that the majority of them are only able to pass the concrete sort task follows Piagetian theory. On the other hand, there was no signi­ ficant difference in performance between first and second graders. It was postulated that the transition to stage III does not occur until around age nine for the normal American child, and not age seven to eight as Piaget suggests. The finding that the children's ability to abstractly categorize, as represented by passing the concept-shift task, in a consistent manner supports the view that it may be more profitable to consider children at this age to be bound by the intensive property of classes to the exclusion of all else. This deviates from the Piagetian view of considering children at this stage to classify in an inconsistent and incomplete manner. The children were given a retest from five to ten days after the first session, using the same tasks but with slightly altered stimuli. Performance on all three tasks was quite consistent. In most cases, the children remained at the same level of performance on the second session. Those children that did show a change in performance only dropped or moved up one level. 62 Finally, the present results have implications for those future researchers interested in expanding upon or reconfirming Piaget's three stage sequence of classificatory development. It may well be that within each major stage there are two substages, representing concrete and abstract levels of functioning. This may especially be true for stage II, as the present data suggest. Further, at stage II the predominance of the intensive mode of responding suggests a slight deviation from Piaget's interpretation of the dynamics of this period. Only future research can resolve the discrepancy.