I)IFFERENTIELLE PSYCHOLOG1E DER JUGENDZEYF 305

I. Leurs choix, comme leurs rejets, soot plus nombreux en r6ponse aux questions de type A qu'en r~ponse aux questions de type B.

2. En A, tes ehoix soot plus nombreux que les rejets.

3. En B, les rcjets son plus nombreux qu'en A.

4. Les sujets les phls choisis en A, nc sont pus systtmatiquement les plus choisis en B.

On en peut conclure que le adolescents ddbiles mentaux, loin de choisir au hasard, soot capables, COmlUe les enfants normaux, d'une activit6 de discrimination fine.

THE M E A N I N G OF TRANSITIONS 1N T H E P I A G E T THEORY

OF M E N T A L D E V E L O P M E N T

GERALD NOELTING Geneva (Switzerland)

At the XV th International Congress of Psychology, Dr. Bgrbel In- beldcr and myself presented some preliminary remarks concerning a longitudinal research which began in 1956 and is still in progress (1). A group of twenty children from Geneva Municipal schools, divided into four age-groups between 4 and 12 years of age, have been sub- mitted at regular intervals to (in all) fifty Piaget experimental situations in various fields of mental processes: making up of classes and series, number, spatial relations, conservation, chance and inductive reasoning. We shall describe here a model, based upon strategies of increasing complexity, which is being used to analyze the mass of results obtained.

Former studies of Piaget showed the existence of a certain number of stages of mental development. These stages correspond to certain levels of equilibrium and their structure can be described in terms of modem algebra (group theory). Various sub-stages however are found in the establishment of an equilibrium. These must be analyzed with precision.

Piaget (2) exp?.ained the elaboration of certain "conservations" through a succession of 4 strategies. Strategy 1 consists in the subject "center- ing" the most striking cue or factor found in the total situation and giving an answer based upon it. Strategy 2, as a reaction to the preced- ing, consists in the subject giving his attention to a complementary

306 THEMA 7

index found ill the total sin~ation. Strategy 3 shows an alternation betaveen these two indices, while strategy 4 indicates their combination.

These strategies in the above mentioned order have been found in several experimental situations studied. The scheme seems to be very general. It is the psychologist's task, however, to determine in each case, which arc the relevant indices centered by the child and which lead, through their reciprocal compensation, to the building up of an in- varant. At the level of concrete operations (6 to 10 years), these in- dices are "dimensions", found in the material, which the child must at the same time differentiate and relate, in the "'Balls of Clay", for in- stance, he is led to compensate width and length to make up the tw'o- dimensional notSon of amount of matter, which remains constant through the various deformations of the object. At the level of formal operations (10 to 15 years), these indices are themselves operational systems al- ready constituted. For instance, the ]avorable and untavorable cases, in an experiment on chance, must be related to all possible cases, thus yielding the notion of likelihood ("Quantification. of Chance").

The existence of strategy. 3 as a sub-stage of transition has been found in several experimental situations. It corresponds to oscillations in the answers of a subject, either between an error and the opposite one, or else (denoting a genetic progress) between an error and the correc~ answer to the problem. In strategy 4 these elroneous answers become pa~ial aspects of the total solution and are integratcd in a cohesive whole, corresponding to the various aspects of the total situation. The processes of differentiation of indices and their integration can be followed up genetically. These processes gradually connect ever more and come into equilibrium. A new stage has been reached.

I~FERENCES

t. INFIELDER, B. et NOELT1NG, G., Le passage d'url stade au sulvant dans Ic d6veloppement des fonctions cognitives. Actes du XWe Congr~s InternationN de Psychologle, Bruxelles, 1957.

2. PIAGET, J., Logiqtte et dquilibre darts le comportemem du sulet. Etudes d'epistrmologie grnftique, II.