Psychology has various definitions, most of them stating that psychology is the study of behavior. Health psychology is the application of psychology to health-related problems and behavior. Most psychological applications in health are from the discipline of social psychology. The contribution of health psychology to public health is in such areas as psychological processes in prevention, health maintenance (e.g., not smoking), and patient education, particularly in helping people cope with an illness (e.g., mastering the use of the peak flow meter to control asthma).
HEALTH PSYCHOLOGY PERSPECTIVES
Health psychology deals with individual behavior in a social context. However, within the public health sector, behavior is not restricted to behavior of at-risk persons, but also includes behaviors of peers, parents, health professionals, employers, politicians, and others. Unfortunately, while there is a large amount of empirical data available regarding individual behavior of the at-risk person or patient, there is very little data available about behaviors at other social levels.
Health psychologists try to understand behavior by describing psychosocial determinants for individual behavior. But health psychologists also try to understand and promote behavior change. One basic assumption in health psychology is that to change people's behavior—at least through health promotion interventions—it is necessary to understand the psychosocial determinants of behavior. For example, when a smoker fails to stop smoking because of a lack of motivation, another type of intervention is required than for a smoker that fails because of a lack of social support.
The first public health applications of psychology were strongly focused on risk perception and risk taking. The best example may be the health belief model, where the perception of the severity of the risk and the susceptibility for the risk were seen as the primary determinants of health-protective behaviors. Over time, it became clear that people have many reasons for health-related behaviors, of which risk perception is often not an important one. In this multicausality approach, there is also a growing recognition of the many psychosocial and environmental influences on individual behavior. Changes in psychosocial determinants (e.g., self-efficacy) are most effective in creating behavior change when paralleled by changes in the social and physical environment(e.g., removal of barriers).
The application of psychological theories to public health is not without debate. Some professionals state that psychological theories will never be able to fully help us understand behavior and behavior change; other professionals claim that in practice there is nothing so helpful as a good theory. Both perspectives are justified. Theories are, by definition, a reduction of reality, but they do help people organize their thoughts and ask the right questions. The interesting contribution of theories is that they can generalize findings from one area of behavior to be of use in another.
PSYCHOSOCIAL DETERMINANTS OF BEHAVIOR
The most often applied theories to explain the psychosocial determinants of behavior are Icek Ajzen's theory of planned behavior and Albert Bandura's social cognitive theory. Social cognitive theory (SCT) specifies the following determinants of behavior: outcome expectations, self-efficacy expectations, behavioral capability, perceived behavior of others (modeling), and the social and physical environment.
The theory of planned behavior (TPB) is an extension of the earlier theory of reasoned action. TPB postulates that intention, the most proximal determinant of behavior, is determined by three conceptually independent constructs: attitude, subjective norms, and perceived behavioral control (or self-efficacy). The attitude towards the behavior is determined by salient beliefs, or outcome expectations, about that behavior. Beliefs are weighted by evaluations or judgments about the value or importance of the expected outcome. For example, the expected outcome of going on a lowfat diet might be a lowering of blood pressure, which could be judged to be important and worthwhile.
Subjective norms, or perceived social expectations, are beliefs that specific, important individuals or groups approve or disapprove of the behavior. These beliefs are weighted by the motivation to comply with the referent person or group—that is, how important is a friend's or group's approval or opinion. Note that Ajzen's perceived social expectations are different from Bandura's perceived behavior of others, where the social environment does not necessarily expect certain behavior. Other authors have broadened the TPB social influence construct to include perceived behavior of others, perceived expectations of others, social pressure, and social support.
Perceived behavior control or self-efficacy refers to the subjective probability that a person is capable of executing a certain action (e.g., going on a low-fat diet might be perceived to be difficult).
Since the theory of planned behavior was introduced in the 1980s, other determinants have been suggested, including: personal moral norms, anticipated regret, identity concerns, and self-evaluation. Another development is an increasing attention to the relation between intentions and behavior. Studies on implementation intention show that helping people to make plans to behave in a certain way can improve the intention-behavior link. Intentions, however, may be overruled by habits. Behaviors become habitual when performed frequently and when performed in a stable environment. Under conditions where habits conflict with intentions, intentions become poor predictors of behavior. It is possible, however, to break bad habits by replacing a habitual sequence with an alternative sequence.
TPB is most often applied at the individual level. However, it has been applied to higher ecological levels as well, such as the voting behavior of legislators regarding a cigarette tax increase, or the adoption behavior of schoolteachers and principles for HIV (human immunodeficiency virus) prevention programs.
THE PSYCHOLOGY OF BEHAVIOR CHANGE
The most prominent psychology theories of behavior change are the social cognitive theory, James Prochaska and Carlo DiClemente's transtheoretical model, Richard Petty and John Cacioppo's elaboration likelihood model, and various theories on coping and self-regulation by authors like Richard Lazarus. Social cognitive theory suggests the following methods for change: active learning, reinforcement, and modeling and guided practice (including feedback).
The transtheoretical model (TTM) has two major sets of constructs: stages of change and processes of change. In the stages of change, people are thought to move from a state of no motivation to change to one of internalization of new behavior. The first stage is "precontemplation," in which people have no intention to change their behavior. In a successful change process, people make a transition to "contemplation," in which they are thinking about changing the problem behavior. Ideally, people then move to "preparation," in which they are planning to change this behavior in the short term. People who have recently changed their behavior are in the "action stage," whereas people who have performed the behavior for a longer time are in the "maintenance stage." People in the action stage may lapse and then recycle to an earlier stage.
TTM can be used to describe and to change behavior. An important contribution of the model is the specific tailoring of educational efforts to include different models and processes of change for individuals in different stages of change. For instance, a re-evaluation of outcome expectations is used to make the change from precontemplation to contemplation; and a guided practice for skills improvement can help with the change from action to maintenance.
Social psychology has a long tradition in persuasion research. Petty and Cacioppo have a new perspective on persuasion effects with their elaboration likelihood model (ELM). The basic idea of ELM is that people differ in their ability and motivation for thoughtful information processing of persuasive messages. These authors explain two ways of information processing, central or peripheral (also called systematic versus heuristic). Central processing occurs when a message is carefully considered and compared against other messages and beliefs. Peripheral processing occurs when a message is processed without thoughtful consideration or comparison. A variable—for instance, the credibility of a sports hero as a model—may have a positive effect when the receivers process the message through the peripheral route, but a negative effect when they follow the central route, because people might realize that their behavioral capabilities are different from those of the sports hero. Research findings suggest that thoughtful information processing is related to a higher persistence of attitude change, a higher resistance to counter-persuasion, and a stronger attitudebehavior consistency. ELM suggests two ways to stimulate central processing: Make the message more personally relevant and unexpected, and repeat the message.
Self-regulatory or self-management conceptualizations, including coping theories, have to do with how individuals function to behaviorally self-correct. Various authors describe this process. The general procedure is: (a) monitoring of some aspect of behavior or health, (b) comparing one's observation with normal or desired outcomes or behavior, describing a problem or divergence from normal, and analyzing the causes of the problem, and (c) trying a behavioral correction. This entire process recycles with a return to monitoring. Self-regulatory theories are useful for the designation of health-promoting behaviors for the self-management of chronic diseases, such as asthma, diabetes, or cystic fibrosis.
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