Michael Hennessy and Daniel Romer are with the Annenberg Public Policy Center, University of Pennsylvania, Philadelphia. Robert F. Valois is with the Arnold School of Public Health, University of South Carolina, Columbia. Peter Vanable is with the Center for Health and Behavior, Syracuse University, Syracuse, NY. Michael P. Carey is with the Centers for Behavioral and Preventive Medicine, The Miriam Hospital and Brown University, Providence, RI. Bonita Stanton is with the School of Medicine, Wayne State...