Responding to recent advances in developmental and cognitive science research on knowledge acquisition, this report presents a theoretical framework for analyzing cognitive development as a process of learning. The first section summarizes three developmental characteristics recognized in both the Piagetian and the quantita experimental tradition: developmental stages, decalage (the inability to transfer concepts to new tasks), and memory deficits. The second section discusses several kinds of explanations that have been postulated for these phenomena, including the ideas that capacity increases with growth and that changes in the kinds and the availability of memory structures create developmental differences. The third section introduces theoretical memory structures and explicit learning mechanisms that have been postulated to operate in two general theories of learning and memory, while the fourth section speculates on how a learning theory embodying these structures and mechanisms might explain the phenomena in the first section. (MM)