the aggregate of the specific educational, scientific, and professional contributions of the discipline of psychology to the promotion and maintenance of health, the prevention and treatment of illnesses, and the identification of etiologic and diagnostic correlates of health, illness and related dysfunction, and to the analysis and improvements of the health care system and health policy formation.
Matarazzoās definition brings us closer to an ecological view of health psychology, one that considers the interrelations between organisms and their environment (Glanz, Rimer, & Viswanath, 2008). Uniquely, ecological models allow us to examine how environmental and policy variables affect health. In addition, the ecological view incorporates the psychological, social, and organizational factors typically included in other models, such as the cognitive-based (also called individual-level) models.
While reading this chapter, it is important to remember that many of the models and theories were (and still are) tested primarily, if not exclusively, in Western cultures. As the authors of several chapters in this handbook remind us, some theories and research methodologies favored in Western cultures are either unsupported or inappropriate when examining global health behaviors and outcomes. The theories may fail to explain behaviors in non-Western cultures because they impose a set of assumptions, beliefs, or values about behaviors that are inconsistent with the examined culture (see Trimble, Chapter 3). Similarly, the measures employed to test these theories may be ill-suited for use in other cultures, or outright rejected, due to their emanation from colonizing countries with troubled histories with non-Western cultures (see Moola & Cilliers, Chapter 18). We will explore some of these critiques in later chapters.
Cognitive-Based vs. Ecological Models
Cognitive-based models (sometimes referred to as individual-level theories or models, Crosby, Kegler, & DiClemente, 2002) focus on the individual as the principal determinant of health outcomes. The popularity of these models appears to be rooted in a number of assumptions about individuals, as well as some inherent strengths and limitations of the research that supports them. Specifically, these theories assume that: 1) individuals place a high value on good health serving as a motivator for behavior or behavior change (Bosworth, Horner, Edwards, & Matcher, 2000; Foster, Frijters, & Johnson, 2012; Ng, Ntoumanis, & Thogersen-Ntoumanis, 2012); 2) individuals also possess sufficient agency and self-efficacy to initiate and sustain behavioral change (Velicer, Prochaska, & Red-ding, 2006); and 3) that an individualās behavior is volitional (Leventhal, Rubin, Leventhal, & Burns, 2001; Schwarzer, 2008). Yet the literature on health behavior change is rife with studies that challenge each of these assumptions (Sheeran, 2002; van Helvoort-Postulart, Dirksen, Kessels, vanEngelshoren, & Huunink, 2009 Vermaire, vanExel, van Loveren & Brouwer, 2012).
Cognitive-based models also lend themselves to analytical designs such as controlled trials or interventions that are empirical and can lead to strong statistical findings (Crosby, et al., 2002). These designs are often the preferred methodologies of psychologists (the field of study of most of this chapterās authors; hence, no disparagement). It is not surprising, therefore, to find a number of controlled trial or intervention studies in the psychological literature to test the effectiveness of cognitive-based models of health behavior change.
By comparison, ecological models of health build on an interdisciplinary approach, studying the relationship between an organization and its environment (Stokols, 1996). Bronfenbrenner (1979) adapted this model to explain child development, suggesting that the child is influenced by and influences the social environment (McLeroy, Bibeau, Steckler, & Glanz, 1988). McLeroy, and colleagues (1988), Stokols (1992), and Stokols, Grzywacz, McMahan, and Phillips (2003) and others later adapted this concept of mutually influencing agents to explain health behaviors. Their newer models divide the environment into smaller analytic levels, and espouse multilevel influences on behaviors, including intrapersonal (biological, psychological, lifestyle choices), interpersonal (social, cultural), and environmental factors (organizations, the physical environment, and policy determinants).
Current ecological health researchers expand McLeroy et al.ās and othersā concept of multilevel influences, identifying four principles common to most such models. First, consistent with the core concept, they contend there are multiple influences on specific health behaviors. Second, these multiple influences interact across different levels. Third, notwithstanding this interaction, ecological models of health should focus on specific behaviors and isolate the primary influences at each level. Finally, the most effective interventions for changing behaviors should be multilevel, consistent with the influences (Sallis, Owen, & Fisher, 2008).
Both cognitive-based and ecological models enjoy robust support from health researchers. Which model researchers choose to test or support may depend largely on their own beliefs about behavior change. What is clear, however, is that ecological models of health behavior represent a paradigm shift away from earlier models that focused on the individual as the primary agent of change to one that sees the individual acting within and reacting to a complex system of factors that drive change (Crosby, et al., 2002).
