Understanding how people learn is the foundation of informed teaching, yet it is difficult for teachers to articulate and effectively use. This study investigated how two preservice teachers' conceptions of learning theories transferred to their decisionmaking during student teaching. This paired-sample case study examined Research-Based Framework papers, oral defenses, student teaching practices, and reflection on-action. Findings indicate that knowledge from a video case analysis assignment given in the science methods course can transfer to classroom decisions during student teaching; however, perceived institutional constraints can override such knowledge, resulting in decisions that meet district requirements yet are knowingly detrimental to students.