Psychologists recognize that understanding how people change is the first step to helping people change their unhealthy behaviors and live longer, healthier lives. In a study involving 872 people who were trying to change their smoking habits, psychologists - including those here at URI - identified five stages of change that became the cornerstone of the Transtheoretical Model (TTM) of Change. Based on this research, psychologists now have a better understanding of not only how people change, but also how to help people in their efforts to change. The TTM has been used to develop numerous individual, and community, behavior change interventions that focus on how people make decisions. Many of these interventions have been shown to reduce the behaviors that put people at greater risk for health problems. Psychologists at URI's Cancer Prevention Research Center, as well as other researchers across the country, have developed TTM-based interventions for topics such as HIV prevention, smoking cessation, increasing seatbelt use, increasing exercise, and adopting a low-fat diet.