The distinction between competence and performance models in psycholinguistics is used to analyze current theory and research strategies in the study of development. The analysis is used to argue for the construction of performance models of cognitive skills which do not reify the elements of competence models. Some suggestions are presented for a performance model which relies on Soviet notions of activity and interpsychological control. The potential theoretical and empirical benefits of the model are discussed in the context of the authors’ research on the deployment of formal operational skills.