In a 1951 study, Erik Erikson reported differences in preadolescents' play constructions. He claimed that his findings reflected differences between males and females in their experience and perception of space. The present study replicated but also expanded the original design. In order to control for possible sex bias of materials, a constructed scene using only blocks was added to Erikson's original design. The results failed to replicate Erikson's findings. In fact, in the construction of scenes from blocks, more females than males built erected structures; this was true across all ages. These findings are in direct contrast to Erikson's results, and they lead to the conclusion that the materials provided, not innate anatomical sex differences, account for the resulting spatial configurations.