Preservice teachers in an Educational Psychology course wrote cases about their field placements and analyzed the cases using perspectives from the learning sciences. The course helped student teachers use the learning sciences to enhance instruction. It engaged them in collaborative problem solving which required them to use theory as a tool for addressing real instructional problems. Student teachers worked in problem-based learning groups to: study cases of actual instruction and redesign instruction to enhance learning; formulate hypotheses about cases to prompt investigation into the content of the learning sciences; use a Secondary Teacher Education Project Web site to guide investigations into relevant learning sciences theories; develop instructional solutions based on their research; and develop analyses of cases from their field experiences. Results indicated that the student teachers tended to use a level 2 situation model for interpreting instruction that they observed or led, meaning that they recognized the importance of student thinking as opposed to only their own explanations and lectures. However, they did not discuss further teacher-student interactions, such as challenging students' conceptions. Results indicated that student teachers were not fully prepared to interact with students and challenge their ideas after the preservice course. (Contains 15 references.) (SM)