Reverse scaffolding

Abstract

In the context of a design-based research effort to develop a technology-enabled constructivist algebra unit, a new activity architecture emerged that steps students through discovery levels. As they build a virtual model of a problem situation, students figure out technical principles for assuring the model's fidelity to the situation. These construction heuristics, we find, are precisely the conceptual foundations of algebra, such as tinkering with the model to assure that the variable quantity is of consistent size throughout the model. We articulated these principles as situated intermediary learning objectives (SILOs). At each interaction level, the student discovers a SILO, and then the technology takes over by automatizing that SILO, thus freeing the student for further discovery. We call this architecture reverse scaffolding, because the cultural mediator thus relieves learners from performing what they know to do, not from what they do not know to do. In a quasi-experimental evaluation study (Grades 4 & 9; n=40), reverse-scaffolding students outperformed directscaffolding students, for whom the technical features were preautomatized. We speculate on the architecture's generalizability.