| Abstract: | A theoretical model of cognitive development is applied to the study of the acquisition of formal operational schemata by adolescents. The model predicts that the proportion of adolescents who have not yet acquired the ability to perform a a specific Piagetian-like task is an exponentially decreasing function of age. The model has been used to analyze the data of two large-scale studies performed in the United States and in Israel. The functional dependence upon age was found to be the same in both countries for tasks which are used to assess the following formal operations: proportional reasoning, probabilistic reasoning, correlations, and combinatorial analysis. Different functional dependence was found for tasks assessing conservation, control of variables, and prepositional logic. These results give support to the “unity” hypothesis of cognitive development, that is, the hypothesis that the various schemata of formal thought appear simultaneously. |
