Piaget's Conservation Experiments

A series of experiments by Jean Piaget testing whether children understand that a quantity remains the same despite a change in its shape or arrangement. In the best known version, two identical rows of counters are shown to a child as equal, one row is then spread out, and the child is asked whether the two rows still contain the same number of counters; parallel tasks tested conservation of solid quantity by reshaping a ball of clay and conservation of weight on a balance scale. Piaget used the results to argue that this understanding is absent during the preoperational stage of development and emerges during the concrete operational stage.