At the university level, science education reform is limited by novice instructors who do not share reformers' educational values. The current challenge is to provide professional development (PD) that will be transformative: rather than merely exposing participants to reform instructional materials, it will change what future instructors believe is worthwhile in science education. Our view is that professional development is most effective when it enriches the intellectual life of teachers and builds teacher identity by cultivating concern with student thinking. In an example of an activity that originates in this perspective, participants interview peers about physics concepts and conduct structured reflections on the interviewing experience. The activity holds promise for improving participants' abilities to listen and to teach effectively, increasing their esteem for the intelligence that teaching requires, and increasing their interest in K-12 physical science teaching as a profession.