Instructors of elementary science methods classes have long lamented the significant difficulties their students exhibit when trying to understand the many complexities of teaching science. As noted by some researchers and practicing teachers, preservice teachers often fail to developmentally function at desired levels with respect to constructivism and constructivist practices. Many reasons exist for continuing to consider developmental perspectives when trying to understand student learning, or lack thereof. Developmental learning theories have matured substantially from Piaget's (1969) original four stage model of child development, or the model later proposed by Kohlberg (1984). However, neither is ideal for understanding the development of perspectives in teacher education students. A model proposed by Perry (1970) examined adult development within the context of college students' thinking and its progression throughout the college experience. In this study, Perry's scheme has been applied to the development of constructivist perspectives in a group of preservice elementary education majors. Results revealed 28 of the 38 students held perceptions in the lowest level (dualism) of Perry's scheme. This calls into question the efficacy of science methods instruction premised on the basis of students functioning at stages above that of dualism. (Contains 1 table and 1 figure.)