Communication is the production and exchange of information and meaning by use of signs and symbols. It involves encoding and sending messages, receiving and decoding them, and synthesizing information and meaning. Communication permeates all levels of human experience and it is central to understanding human behavior and to nearly all public health efforts aimed at fostering health behavior change among individuals, populations, organizations, communities, and societies.
Communication may be studied empirically and critically at different levels of interaction. These levels, often described on a "micro-to-micro" continuum are "intra-personal" (how individuals process information), "inter-personal" (how two individuals interact to influence one another), group (how communication dynamics occur among many individuals), formal and informal "organizations" (how communication occurs and functions in the context of organizations such as hospitals, schools, or public health agencies), and "community" and "society" (how communication builds or changes the agenda of important issues).
Empirical study means applying scientific methods to the study of communication; as in the study of behavior change resulting from exposure to a communication campaign. Critical study means applying methods of cultural, literary, or normative criticism to the study of communication; as in the analysis of how media content creates health-related meaning and influences behavioral norms through commercial advertising or entertainment.
Many fields emphasize the importance of communication theory as a basis for understanding human behavior. For the field of public health, the use of applied communication perspectives involves how communication activity positively or negatively contributes to health behavior, and how the planned use of communication influences health behavior within the context of health education and health promotion.
ORGANIZATION OF COMMUNICATION STUDIES
Communication scholar George Gerbner describes three main branches of communication study. The first is "semiotics," the study of signs and symbols and how they combine to convey meaning in different social contexts. This branch is mainly concerned with how verbal, nonverbal, visual, and aural signs and symbols combine to create messages.
The second branch, media effects, is the study of behavior and interaction through exposure to messages. It emphasizes measuring, explaining, and predicting communication effects on knowledge, perceptions, beliefs, attitudes, and public opinion. It is strongly influenced by scientific methods from the fields of psychology and social psychology.
The third branch, message production, is the study of the large-scale organization of communications through social institutions and systems (mass media, political organizations, government, advocacy groups), their history, regulation, and policy-making impact. It is strongly influenced by scientific methods from the field of sociology, but also by the methods of political science, history, and public affairs.
Just as no single behavioral theory explains and predicts all human behavior, no communication theory explains and predicts all communication outcomes. Some view this as a fragmentation in understanding the role of a communication in human affairs. Others view this as a productive theoretical diversity, conducive to the understanding of human activity in many complex dimensions. Communication researchers have increasingly sought to connect and to integrate effects across levels of analysis, from the "micro" to the macro. For example, health campaign planners may study the effects of a media campaign in generating interpersonal discussion. They might look at media story about a new drug or treatment to see if it causes patients to raise the issue with their health care providers.
COMMUNICATION THEORY AND HEALTH BEHAVIOR CHANGE STRATEGIES
How does communication theory inform health behavior change strategies?
Major theories of health behavior change all include communication processes. Value expectancy theories such as the health belief model and the theories of rational behavior and planned behavior depend on communication processes to catalyze health behavior change. The health belief model holds that individuals will be more likely to change their health-related behavior if they recognize a health risk or condition as important, if they view themselves as susceptible to the risk or condition and if they regard the benefits of change as outweighing barriers to making change. Communication strategies play a key role in influencing these perceptions. Similarly, communication plays an important role in influencing perceptions critical to the theories of reasoned action and planned behavior. In these theories, behavior is principally influenced by intentions to change. Intentions are influences by people's attitudes toward a specific behavior as well as their perceptions of what important referent groups think about the behavior. Communication may play a key role in influencing perceptions on both counts and thereby raise the likelihood of behavior change.
While communication dynamics in these theories are aimed principally at catalyzing health behavior change among individuals, other theories include the use of communication to affect change at the level of the community and society as well. The social cognitive theory of Albert Bandura (1986) and the transtheoretical model of Jams Prochaska et al. (1994), for example, recognize that an individuals' behavior is formed in the context of the larger community and social environment. Therefore planned interventions must include efforts to change the larger environment as well. From this perspective, communication has a role to play in influencing community and societal change in areas such as building a community agenda of important public health issues, changing public health policy, allocating resources to make behavior change easier, and legitimizing new norms of health behavior.
Community-based approaches to public health interventions and campaigns gained currency in public health during the last quarter of the twentieth century. This approach recognizes the need to seek change in health behavior across multiple levels of human experience—from the individual to the community level. Campaigns are planned efforts that seek different dimensions of change that will lead to health improvement throughout the population.
THE ROLE OF MEDIA COMMUNICATION
Because public health is interested primarily in populations, media communication is a key part of multistrategy, community-based campaigns. This is the case whether the object is to build a community's agenda for prevention, to change public policy, to educate individuals about specific health behavior changes, or all of these. Media institutions play a crucial role in health behavior change because of their role in disseminating information. As agents of socialization, like other major institutions, they also have a powerful impact in legitimizing behavioral norms. Popular and academic perspectives both hold that media communication plays a powerful role in promoting, discouraging, or even inhibiting healthy behaviors.
One type of research with applied implications for public health deals with message production. It seeks to understand the social and organizational factors that may impinge on the creation of media messages. Public health interest in this research centers around how it may influence message production processes in ways more conducive to creating messages about healthful behavior. The definition of a public health problem influences how the public understands it, the actions individuals or communities are likely to take to affect the problem, and the attention given the problem by different groups. The same processes may be used to influence entertainment content as well. The Harvard School of Public Health, for example, mounted a successful campaign to persuade television producers to include messages about the importance of the designated driver in reducing alcohol-related traffic accidents in there programs.
The second type of research studies the consequences of media exposure on individuals, groups, institutions, and social systems. The focus here is on major media effects hypotheses and their relevance to health behavior change. At the level of the individual, for example, researchers have studied learning hierarchies in which knowledge change affects attitudes, which in turn affects behavior. Others have noted different hierarchies, including dissonance-attribution, in which behavior change precedes attitude change, which in turn affects knowledge, and the low-involvement hierarchy, in which knowledge change precedes behavior, which in turn affects attitudes. Researchers, such as S. Chaffee and C. Roser (1986), have suggested that there are not three distinct hierarchies of effects, but a single continuum. The order of effects depends on where individuals or groups are positioned on this continuum with respect to a given outcome. In public health campaign settings, intervention and communication strategies will depend on an assessment of audience characteristics and needs, and on the development of appropriate messages.
Similarly, persuasion studies have focused on the chain of individual-level communication processes leading to behavior change. Early studies focused on opinion or attitude change in the context of such variables as the credibility of the information source, fear, organization of arguments, the role of group membership in resisting or accepting communication, and personality differences. Since the 1960s, however, research has emphasized cognitive processing of information leading to persuasion. This change occurred partly because of the interest Latin American scholars shown in developing new approaches to the use of mass communication in order to guide social change projects in developing countries.
Social structure has played an increasingly important role in the application of communication strategies to health behavior change. A continuing and perplexing issue involves the influence of social structure on communication and media use, and how this affects health behavior change. Epidemiological studies suggest, for example, that the health "gap" between higher and lower socioeconomic status groups in the United States is worsening rather than improving. Communication contributes to these circumstances insofar as structural barriers of access and exposure are frequently ignored or overlooked. Research has long demonstrated that knowledge and information are not equally distributed across populations. Early studies, such as those of Hyman and Sheatsley (1947), and Mosteller and Moynihan (1972), showed that people with more formal education learned and knew more about many issues, including health, than people with less formal education. These findings were formally presented as the knowledge gap hypothesis by Minnesota researchers P. J. Tichenor, G. A. Donohue, and C. N. Olien (1970). They proposed that increasing flow of information into a social system is more likely to benefit groups of higher socioeconomic status. The disturbing implications were, of course, that public campaigns would only perpetuate inequities. Because this called into question the entire basis of guided social change efforts, it attracted the attention of scholars and policy makers alike. Fortunately, subsequent studies found that knowledge gaps were not intractable. Researchers discovered a variety of contributory conditions that could reduce knowledge gaps. These conditions include content domains (some subjects are intrinsically more relevant to people, such as their health), channel influence (some channels are used more, and have greater impact, on certain groups), social conflict and community mobilization, the structure of communities, and individual motivational factors.
FUTURE DIRECTIONS
The use of communication to achieve health behavior change is now a staple of public health intervention methods, and will continue to be influential in the twenty first century. Researchers are interested in how communication at each level of analysis may influence or link to communication at other levels to affect health outcomes. Social cognitive theorist Albert Bandura recently suggested that the "power" of any single channel of communication (mass media or interpersonal) may depend on the complexity of the behavior change being sought. The less complex the change, the more the influence of a single channel may lead to performance of the behavior. On the other hand, the more complex the behavior, the greater the individuals' need for multiple exposure to multiple sources.
The emergence of new communication technologies also provides opportunities and challenges to public health. The World Wide Web, newsgroups, and other Internet innovations offer information on an array of topics from diverse sources. The nature of the medium also permits information to be available "on demand" to users. Thus, it appears that users can exert a greater degree of control in obtaining the information they seek. However, there is a potentially serious problems that warrant closer examination. New media technologies have the potential to widen the gap between those who can pay for access and gain the necessary skills, and those who cannot. If so, a significant portion of the population may once again be "out of the loop" of important health information and consequently health behavior change.
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