This study examined whether Piagetian logical reasoning abilities and/or an information-processing capacity are needed to learn basic measurement concepts. First-grade children, equated for prior knowledge of measurement but differing in developmental status, were instructed individually on linear measurement. Results showed that the Piagetian reasoning abilities of length conservation and transitivity were required to learn some measurement concepts but not others. It appears that the effects of these cognitive abilities are task specific and, in this sense, are not useful as general measures of learning readiness. Information-processing capacity, as measured by backward digit span, had no detectable effect on learning success.