Conclusions

THERE is a fairly extensive literature which deals with the development of classification and a number of published works deal specifically with sériation. Some of the most outstanding work in the field has been that of Goldstein and his collaborators, notably M. Scheerer. Goldstein and Scheerer ¹ analysed behaviour in “categorization” from the point of view of the abstractions involved. It is to these workers that we owe the notion of the opposition between flexibility or ease of “shifting” and rigidity in categorization. Goldstein and Scheerer’s “sorting-test” consists of 33 common objects which the subject is asked to arrange in as many ways as possible; he may also be asked to define classes as constructed by the tester. Reichard, Schneider and Rapaport ² studied this sort of behaviour in children, as also did Thompson. ³ As early as 1937, Hanfmann and Kasanin, ⁴ basing themselves on the work of Ach (together with certain modifications introduced by Sacharov and Vigotsky), were able to devise a test of classification using 22 blocks. The objects differ from one another in colour (5 shades), in shape (4), in height (2) and in width (2). The subject is told to divide them into four groups: the solution demands flexibility and persistence; fluidity of thinking is essential, while rigidity hinders the correct solution. The ideas of Goldstein led Wallon to posit a “pre-categorizing” level in children’s thinking, which is one manifestation of pre-operational thinking in general. A former collaborator of ours, G. Ascoli, also carried out a study of children’s classifications under Wallon’s direction. ⁵ In addition, the ideas of Gestalt psychology inspired R. Meili in his work on classificatory structures. ⁶