Abstract
Although peer-based work is encouraged by theories in developmental psychology and although classroom interventions suggest it is effective, there are grounds for recognizing that young pupils find collaborative learning hard to sustain. Interpretations of this observation are discussed; it is suggested that these interpretations have been preoccupied with possible discontinuities in collaborative skill during development. Consequently, theory and research have neglected situational continuities between formal and (more successful) informal collaborations. An argument is developed for attending more carefully to the environments of joint problem solving and how they may be fashioned to resource the interactions of collaborators. The place of new educational technology within this enterprise is considered.