Communication theory is a proposed description of communication phenomena, the relationships among them, a storyline describing these relationships, and an argument for these three elements. Communication theory provides a way of talking about and analyzing key events, processes, and commitments that together form communication. Theory can be seen as a way to map the world and make it navigable; communication theory gives us tools to answer empirical, conceptual, or practical communication questions. Communication is defined in both commonsense and specialized ways. Communication theory emphasizes its symbolic and social process aspects as seen from two perspectives—as exchange of information (the transmission perspective), and as work done to connect and thus enable that exchange (the ritual perspective). Sociolinguistic research in the 1950s and 1960s demonstrated that the level to which people change their formality of their language depending on the social context that they are in. This had been explained in terms of social norms that dictated language use. The way that we use language differs from person to person. Communication theories have emerged from multiple historical points of origin, including classical traditions of oratory and rhetoric, Enlightenment-era conceptions of society and the mind, and post-World War II efforts to understand propaganda and relationships between media and society. Prominent historical and modern foundational communication theorists include Kurt Lewin, Harold Lasswell, Paul Lazarsfeld, Carl Hovland, James Carey, Elihu Katz, Kenneth Burke, John Dewey, Jurgen Habermas, Marshall McLuhan, Theodor Adorno, Antonio Gramsci, Robert E. Park, George Herbert Mead, Joseph Walther, Claude Shannon and Stuart Hall—although some of these theorists may not explicitly associate themselves with communication as a discipline or field of study. Models and Elements of Communication Theory One key activity in communication theory is the development of models and concepts used to describe communication. In the Linear Model, communication works in one direction: a sender encodes some message and sends it through a channel for a receiver to decode. In comparison, the Interactional Model of communication is bidirectional. People send and receive messages in a cooperative fashion as they continuously encode and decode information. The Transactional Model assumes that information is sent and received simultaneously through a noisy channel, and further considers a frame of reference or experience each person brings to the interaction. Some of the basic elements of communication studied in communication theory are: Source: Shannon calls this element the "information source", which "produces a message or sequence of messages