A model demonstrates how low correlations for academic achievement in separate units of instruction can be compatible with high correlations for cumulated achievement. The unit achievement is assumed to consist of a task-specific part and a part correlated with a predictor. When units of learning are cumulated, attrition of earlier learning takes…

A Paradigm for testing concept attainment, comprised of twelve tasks, was formulated. These tasks were hypothesized to form a cumulative hierarchy. Tests were constructed in mathematics and social studies using the paradigm. Data for these tests was analyzed by Kaiser's method for fitting a perfect simplex and Schonemann's method for fitting a…

The longitudinal interrelations among age, visual and auditory short-term memory, and the concrete operational tasks of class inclusion and combinatorial reasoning were investigated over four testing occasions in a sample of 134 students, initially ranging from 5 to 12 years in age. The Piagetian task battery involved placement of colored…