ABSTRACT
This chapter deals with the question of why young children fail Piaget's number conservation and class-inclusion tasks. Piaget considered that the child's problem is that he is perceptually dominated and—the other side of the same coin—that he lacks reversible thought. The 'conceptual deficit' view of failure on the conservation and class-inclusion tasks has proved controversial. M. Donaldson adduced this result as evidence against Piaget's view of number conservation failure and for the misinterpretation hypothesis. One could devise a misinterpretation hypothesis that would be consistent with the data. And the same thing is true for the case of the covering and number conservation tasks. The conclusions which have been drawn in these studies may be criticised. One can argue that the findings support the misinterpretation hypothesis and contradict Piaget's position only if the new task is as difficult as the conservation or class-inclusion task.
