Because so much of composition's core pedagogy takes a reflective learning model for granted, we consider a cognitive perspective essential in preparing new composition teachers. Here we describe how such a perspective informs our work with graduate teaching assistants. First, we model how discussion of current pedagogical topics can be situated in a cognitive frame, calling attention in particular to the critical role of metacognitive awareness in curricular models such as writing about writing (WAW) and in pedagogical practices such as multimodal composing. Then we describe an activity designed to help Graduate Teaching Assistants (GTAs) explore implications of a cognitive perspective for their own pedagogical decision-making. Working from data collected from GTA cohorts over a 10-year period, we examine learning style preferences and variability in the GTA population in comparison with published data on undergraduates from various institutions and disciplines. We use these data to examine cognitive variability in writing classrooms and to illustrate a deliberate instructional focus on learning and metacognitive awareness. Our goal throughout is to help GTAs understand the cognitive core that grounds so much of the discipline's pedagogical practice.