RESUMO
We examined apprenticeship, in the form of interaction with a more capable other, as a mechanism of development of higher-order reasoning skills, specifically argumentation. Over a 1-year period, middle school students engaged in twice-weekly electronic dialogs with a sequence of different peers on a series of social issues. In one group, unbeknownst to participants, a highly capable adult substituted for peers in half of their dialogs. Beginning immediately, increasing with time, and extending to peer-only dialogs on a new topic, the quality of argumentation shown by the experimental group exceeded that of a comparison peer-only group, highlighting the power of apprenticeship as a mechanism in the development of reasoning, a demonstration of both theoretical and applied significance.