As an example, two aspects of children's conservation are explained: decalages and the shift from perceptual to quantitative cues. This approach, relative to structuralist formulation, involves cognitive factors such as prior learning, as well as impinging social experience. It is compatible with Piaget's theory, yet simpler and more flexible. (CP)

This study tested certain implied predictions regarding conceptual learning at each of four sequential levels of development: concrete level, identity level, classificatory level, and formal level. For this purpose, scaled batteries to assess the level of conceptual development of children, kindergarten through high school, were constructed and a…