Demonstrations of cognitive competence in preschool children and infants played an important role in the waning influence of Piagetian theory and the rise of nativism. Arguments and data favoring modularity have further buttressed the casefor nativism. This article reviews evidence concerning early competence and modularity in the spatial and quantitative domains, as well as the role of experience in development. This evidence provides little reason to support nativist claims in either domain.