This paper describes a study which utilized Kitchener and King's (1985) Reflective Judgment model to assess levels of reflectivity in 80 undergraduate students at Southern Illinois University, Carbondale, before and after taking a one-semester general studies course with an environmental focus. A curricular intervention was designed to help students examine their epistemic perspectives. One treatment and two control groups were used. All participants were individually administered Kitchener and King's Reflective Judgment Interview (RJI). For the first time in reflective judgment research, this study demonstrated that a purposefully structured one-semester intervention can result in epistemic development. Those students who were exposed to the one-semester developmental instruction approach had significantly higher reflective judgment change scores in comparison to students who were not exposed to such an approach. This study involved the development and implementation of the Reflective Judgment-Developmental Instruction Model (RJ-DIM) (Kronholm, 1993), and this pedagogical approach can be credited for the positive gains found. (Contains 5 tables and 32 references.) (Author/SLD)