Our society is preoccupied with health. Health care is the biggest industry in the United States (Kaplan, Sallis, & Patterson, 1993), and the media routinely inundate us with messages about what is good and bad for our health and the latest medical treatments for a variety of health problems. This concern with health is amply justified, because some modicum of physical health is a necessary precondition for virtually everything that we do.
What compromises our health has changed dramatically over the last 100 years. Infectious diseases were the primary threats to health at the beginning of the 20th century. Since that time, technological innovations in vaccinations, medications, sewage disposal, water treatment, and food preservation have reduced significantly mortality and morbidity that is due to infectious disease. With the exception of AIDS, the main threats to health in the contemporary United States are chronic diseases, such as cardiopulmonary disease, cancer, diabetes, and stroke. These health problems typically develop slowly over long periods of time, are persistent, and have important relations with lifestyle and individuals' behavior. That is, these chronic diseases are at least partly attributable to substance abuse (especially cigarettes and alcohol), poor diet, and lack of exercise. As succinctly stated by Knowles ( 1977), "Over 90 percent of us are born healthy and suffer premature death and disability only as a result of personal misbehavior and environmental conditions" (p. 1104). Diseases attributable in part to health behavior cause inestimable human suffering and staggering economic costs. Manning, Keeler, Newhouse, Sloss, and Wasserman, ( 1991) have estimated that each pack of cigarettes smoked, each alcoholic drink consumed, and each mile not traveled on foot costs our society 15 cents, 22 cents, and 24 cents, respectively, for a total annual bill of hundreds of billions of dollars.
Health behavior obviously deserves the extensive attention it has received from the relevant scientific disciplines. Psychological science has played a major role in studying health behavior, and health psychology is a thriving arena of applications. It therefore is fair to ask what yet another