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.