Past research on decision support systems has focused on numerous functional capabilities and decision outcomes. The findings of this stream of research are contradictory and the empirical evidence supporting competing viewpoints is overwhelming. A plausible explanation of these equivocal results is that most studies have been poorly grounded in theory and overlooked important characteristics of the decision process. In particular, improvements in a manager's information-processing capabilities have been acknowledged conceptually, but treated only in passing. This paper draws on cognitive perspectives on individual learning and develops a theoretical approach to address the unexplored question of how the use of a decision support system contributes to refine a manager's mental models of the business environment and improve the effectiveness of decision making. Implications of the proposed framework and future research directions are discussed.