Individual and situational variability in cognitive development

The purpose of this article is to argue that individual differences should be taken into consideration when suggesting a model of cognitive development. Hence, a multidimensional perspective should be adopted, in which several underlying, independent processes are considered to codetermine performance; this leads to the hypothesis that different developmental paths can exist for different types of subjects. A brief review of how individual differences have been dealt with in developmental psychology is first provided. Then, a three-phase longitudinal study is presented as an empirical illustration. In the first phase, a sample of subjects ranging in age from 6 to 12 years were examined with eight Piagetian tasks. In the second phase, the same subjects were examined again 3 years later with the same tasks. The results from the first two phases are very briefly summarized, stressing intraindividual differences. In the third phase, which took place 8 years later, follow-up of the school records was obtained, and it was possible to distinguish several groups of students on the basis of their postcompulsory schooling. Several hypotheses are advanced, but they are only partially supported by the results for the potential relations between types of schooling on the one hand, and for the modes of processing inferred from the intraindividual patterns observed in the Piagetian tasks on the other.