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.