He earned a Ph.D. at the University of Illinois at Urbana-Champaign, working with Richard Anderson and William Brewer. He is the current Editor of the journal Educational Psychologist. His research focuses on reasoning and argumentation, epistemic practices and epistemic cognition, conceptual change, and collaborative learning. In one line of current research, he is working with Ravit Golan Duncan on a grant from the National Science Foundation to investigate methods of scaffolding the growth of scientific reasoning and content understanding among middle-school science students during model-based inquiry. In a second, closely related line of research, he is exploring new ways of conceptualizing epistemic cognition, drawing on philosophical work to suggest new avenues for empirical research.