Knowing in the context of acting: The task dynamics of the A-not-B error

The A-not-B error is one of the most robust and highly studied phenomena in developmental psychology. The traditional Piagetian interpretation is that the error reflects the immaturity of infants' understanding of objects as permanent entities. More recently, the error has been interpreted in terms of changes in representation, in memory, in spatial knowledge, and in inhib itory processes. Each account may be partially right but none offers a unif ied account of the many accumulated facts about this error. This article pr esents and tests a new unified explanation. The authors propose that the pe rseverative reach back to A is the product of the processes that take a han d to a location in visual space: the body-centered nature of the spatial co de, memories for previous reaching activity, and the close coupling of look ing and reaching. The results from 6 experiments support this explanation. The results are used to challenge the idea of knowledge independent of and distinct from behavior.