How do children learn and how are new modes of thought developed? These questions have for years been of paramount interest to psychologists and others concerned with the cognitive development of the child. In this major work, originally published in 1974 and reporting on over ten years' research of the Geneva School, the authors carried the pioneering investigations of Jean Piaget to a new and remarkable level. As Piaget said in his foreword to the book: 'The novelty of the findings, the clarity of the theoretical interpretation, and the sometimes even excessive caution of the conclusions enable the reader to separate clearly the experimental results from the authors' theoretical tenets.' The authors' learning experiments with children were designed to examine the processes that lead to the acquisition of certain key concepts, such as conservation of matter and length. Detailed study of the progress of each individual subject revealed a number of features characteristic of situations that create conflicts in the child's mind and certain regularities in the way these conflicts are resolved. Such data threw new light on the dynamics of the development of cognitive structures as well as on basic mechanisms of learning at the time.

How do children learn and how are new modes of thought developed? These questions have for years been of paramount interest to psychologists and others concerned with the cognitive development of the child. In this major work, originally published in 1974 and reporting on over ten years' research of the Geneva School, the authors carried the pioneering investigations of Jean Piaget to a new and remarkable level. As Piaget said in his foreword to the book: 'The novelty of the findings, the clarity of the theoretical interpretation, and the sometimes even excessive caution of the conclusions enable the reader to separate clearly the experimental results from the authors' theoretical tenets.' The authors' learning experiments with children were designed to examine the processes that lead to the acquisition of certain key concepts, such as conservation of matter and length. Detailed study of the progress of each individual subject revealed a number of features characteristic of situations that create conflicts in the child's mind and certain regularities in the way these conflicts are resolved. Such data threw new light on the dynamics of the development of cognitive structures as well as on basic mechanisms of learning at the time.

The studies presented in this book should be of interest to anybody concerned with the teaching of arithmetic to young children or with cognitive development in general. The 'eaching experiment. was carried out with half a dozen children entering first grade over two years in biweekly sessions. Methodologically the authors' research is original. It is a longitudinal but not a naturalistic study, since the experimenter-teachers directed their interaction with each individual child with a view to his or her possible progress. It is experimental in the sense that two groups of subjects were selected according to criteria derived from an earlier study (Steffe, von Glasersfeld, Richards & Cobb, 1983) and that the problems proposed were comparable, though far from identical across the subjects; but unlike more rigid and shorter "learning" or ''training" studies it does not include pre-and posttests, or predetermined procedures. Theoretically, the authors subscribe to Piagefs constructivism: numbers are made by children, not found (as they may find some pretty rocks, for example) or accepted from adults (as they may accept and use a toy). The authors interpret changes in the children's counting behaviors in terms of constructivist concepts such as assimilation, accommodation, and reflective abstraction, and certain excerpts from protocols provide on-line examples of such processes at work. They also subscribe to Vygotsky's proposal for teachers '0 utilize the zone of proximal development and to lead the child to what he (can) not yet do. (1965, p. 104)."