An important facet of inclusive, student-centered science teaching is for college instructors to reveal and respond to student thinking. Professional development (PD) provides formal settings for instructors to develop skills attending and responding to student ideas in their teaching. Using the lens of sociocultural theory, the purpose of this study was to explore the learning experiences of college instructors in long-term faculty learning communities (FLCs) that focused on student thinking. This study employed a qualitative design using semistructured interviews, analyzed through qualitative thematic analysis. We investigated the ways that social interactions focused on artifacts of student learning facilitated college instructors' internalization of knowledge about teaching and learning. We found that participants valued the social space of the FLC for the camaraderie and diverse perspectives it facilitated and that participants internalized the discussions from their FLCs in the form of new insights into student thinking and plans for improving teaching. Our data support the idea that PD for college science teaching that includes social space focused on artifacts of student learning will lead to instructor learning. Further, our data point to the fruitfulness of new research to expand our knowledge of the implications of sociocultural theory for college science PD.