In Chapter 2, Holtgrave, Tinsley, and Kay described stages of change theory and illustrated how behavioral decision-making principles inform messages designed to encourage people through the initial steps of behavior change. We, too, will base our message design recommendations on a stages of change approach, but rather than draw on the decision-making literature, we will examine Bandura's social cognitive theory and its implications for moving people to behavior change in a staged fashion. To this end, we briefly review both the transtheoretical model and social cognitive theory, and then describe and illustrate social cognitive message design strategies to move ...