This study examined instructional shifts associated with teaching in environments optimized for active learning, including how faculty made decisions about teaching and their perceptions of how students responded to those changes. The interviews and subsequent analysis reveal a broad range of course changes, from small modifications of existing activities to large shifts towards collaborative learning, many of which emerged during the term rather than being planned in advance. The faculty discuss several factors that influenced their decisions, including prior experience, professional identity, student engagement, as well as perceived and realized affordances of the environments.