Models of communication
- Related Topics:
- language
- public opinion
- animal communication
- information theory
- sign
- On the Web:
- HistoryWorld - History of Communication (June 18, 2025)
Fragmentation and problems of interdisciplinary outlook have generated a wide range of discussion concerning the ways in which communication occurs and the processes it entails. Most speculation on these matters admits, in one way or another, that the communication theorist’s task is to answer as clearly as possible the question, “Who says what to whom with what effect?” (This query was originally posed by the U.S. political scientist Harold D. Lasswell.) Obviously, all the critical elements in this question may be interpreted differently by scholars and writers in different disciplines.
Linear models
One of the most productive schematic models of a communications system that has been proposed as an answer to Lasswell’s question emerged in the late 1940s, largely from the speculations of two American mathematicians, Claude Shannon and Warren Weaver. The simplicity of their model, its clarity, and its surface generality proved attractive to many students of communication in a number of disciplines, although it is neither the only model of the communication process extant nor is it universally accepted. As originally conceived, the model contained five elements—an information source, a transmitter, a channel of transmission, a receiver, and a destination—all arranged in linear order. Messages (electronic messages, initially) were supposed to travel along this path, to be changed into electric energy by the transmitter, and to be reconstituted into intelligible language by the receiver. In time, the five elements of the model were renamed so as to specify components for other types of communication transmitted in various manners. The information source was split into its components (both source and message) to provide a wider range of applicability. The six constituents of the revised model are (1) a source, (2) an encoder, (3) a message, (4) a channel, (5) a decoder, and (6) a receiver. For some communication systems, the components are as simple to specify as, for instance, (1) a person on a landline telephone, (2) the mouthpiece of the telephone, (3) the words spoken, (4) the electrical wires along which the words (now electrical impulses) travel, (5) the earpiece of another telephone, and (6) the mind of the listener. In other communication systems, the components are more difficult to isolate—e.g., the communication of the emotions of a fine artist by means of a painting to people who may respond to the message long after the artist’s death.
Begging a multitude of psychological, aesthetic, and sociological questions concerning the exact nature of each component, the linear model appeared, from the commonsense perspective, at least, to explain in general terms the ways in which certain classes of communication occurred. It did not indicate the reason for the inability of certain communications—obvious in daily life—to fit its neat paradigm.
Entropy, negative entropy, and redundancy
Another concept, first called by Shannon a noise source but later associated with the notion of entropy (a principle derived from physics), was imposed upon the communication model. Entropy is analogous in most communication to audio or visual static—that is, to outside influences that diminish the integrity of the communication and, possibly, distort the message for the receiver. Negative entropy may also occur in instances in which incomplete or blurred messages are nevertheless received intact, either because of the ability of the receiver to fill in missing details or to recognize, despite distortion or a paucity of information, both the intent and content of the communication.
Although rarely shown on diagrammatic models of this version of the communication process, redundancy—the repetition of elements within a message that prevents the failure of communication of information—is the greatest antidote to entropy. Most written and spoken languages, for example, are roughly half-redundant. If 50 percent of the words of this article were taken away at random, there would still remain an intelligible—although somewhat peculiar—essay. Similarly, if one-half of the words of a radio news commentator are heard, the broadcast can usually be understood. Redundancy is apparently involved in most human activities, and, because it helps to overcome the various forms of entropy that tend to turn intelligible messages into unintelligible ones (including psychological entropy on the part of the receiver), it is an indispensable element for effective communication.
Messages are therefore susceptible to considerable modification and mediation. Entropy distorts, while negative entropy and redundancy clarify; as each occurs differentially in the communication process, the chances of the message being received and correctly understood vary. Still, the process (and the model of it) remains conceptually static, because it is fundamentally concerned with messages sent from point to point and not with their results or possible influences upon sender and receiver.
Feedback
To correct this flaw, the principle of feedback was added to the model and provided a closer approximation of interpersonal human interaction than was known theretofore. This construct was derived from the studies of Norbert Wiener, the so-called father of the science of cybernetics. Wiener’s cybernetic models, some of which provide the basis for current computer technology, were designed to be responsive to their own behaviour; that is, they audited their own performances mathematically or electronically in order to avoid errors of entropy, unnecessary redundancy, or other simple hazards.
Certain types of common communications—holiday greeting cards, for instance—usually require little feedback. Others, particularly interactions between human beings in conversation, cannot function without the ability of the message sender to weigh and calculate the apparent effect of his words on his listener. It is largely the aspect of feedback that provides for this model the qualities of a process, because each instance of feedback conditions or alters the subsequent messages.
Dynamic models
Other models of communication processes have been constructed to meet the needs of students of communication whose interests differ from those of quantitatively oriented theorists like Shannon, Weaver, and Wiener. While the model described above displays some generality and shows simplicity, it lacks some of the predictive, descriptive, and analytic powers found in other approaches. A psychologist, Theodore M. Newcomb, for example, has articulated a more fluid system of dimensions to represent the individual interacting in his environment. Newcomb’s model and others similar to it are not as precisely mathematical (quantitative) as Shannon’s and thus permit more flexible accounts of human behaviour and its variable relationships. They do not deny the relevance of linear models to Shannon and Weaver’s main concerns—quanta of information and the delivery of messages under controlled conditions—but they question their completeness and utility in describing cognitive, emotional, and artistic aspects of communication as they occur in sociocultural matrices.
Students concerned mainly with persuasive and artistic communication often centre attention upon different kinds, or modes, of communication (i.e., narrative, pictorial, and dramatic) and theorize that the messages they contain, including messages of emotional quality and artistic content, are communicated in various manners to and from different sorts of people. For them the stability and function of the channel or medium are more variable and less mechanistically related to the process than they are for followers of Shannon and Weaver and psychologists like Newcomb. (McLuhan, indeed, asserts that the channel actually dictates, or severely influences, the message—both as sent and received.) Many analysts of communication, linguistic philosophers, and others are concerned with the nature of messages, particularly their compatibility with sense and emotion, their style, and the intentions behind them. They find both linear and geometric models of process of little interest to their concerns, although considerations related to these models, particularly those of entropy, redundancy, and feedback, have provided significant and productive concepts for most students of communication.
Applications of formal logic and mathematics
Despite the numerous types of communication or information theory extant today—and those likely to be formulated tomorrow—the most rationally and experimentally consistent approaches to communication theory so far developed follow the constructions of Shannon and others described above. Such approaches tend to employ the structural rigours of logic rather than the looser syntaxes, grammars, and vocabularies of common languages, with their symbolic, poetic, and inferential aspects of meaning.
Cybernetic theory and computer technology require rigorous but straightforward languages to permit translation into nonambiguous, special symbols that can be stored and utilized for statistical manipulations. The closed system of formal logic proved ideal for this need. Premises and conclusions drawn from syllogisms according to logical rules may be easily tested in a consistent, scientific manner, as long as all parties communicating share the rational premises employed by the particular system.
That this logical mode of communication drew its frame of discourse from the logic of the ancient Greeks was inevitable. Translated into an Aristotelian manner of discourse, meaningful interactions between individuals could be transferred to an equally rational closed system of mathematics: an arithmetic for simple transactions, an algebra for solving certain well-delimited puzzles, a calculus to simulate changes, rates and flows, and a geometry for purposes of illustration and model construction. This progression has proved quite useful for handling those limited classes of communications that arise out of certain structured, rational operations, like those in economics, inductively oriented sociology, experimental psychology, and other behavioral and social sciences, as well as in most of the natural sciences.
The basic theorem of information theory rests, first, upon the assumption that the message transmitted is well organized, consistent, and characterized by relatively low and determinable degrees of entropy and redundancy. (Otherwise, the mathematical structure might yield only probability statements approaching random scatters, of little use to anyone.) Under these circumstances, by devising proper coding procedures for the transmitter, it becomes possible to transmit symbols over a channel at an average rate that is nearly the capacity of units per second of the channel (symbolized by C) as a function of the units per second from an information source (H)—but never at rates in excess of capacity divided by units per second (C/H), no matter how expertly the symbols are coded. As simple as this notion seems, upon determining the capacity of the channel and by cleverly coding the information involved, precise mathematical models of information transactions (similar to electronic frequencies of energy transmissions) may be evolved and employed for complex analyses within the strictures of formal logic. They must, of course, take into account as precisely as possible levels of entropy and redundancy as well as other known variables.
The internal capacities of the channel studied and the sophistication of the coding procedures that handle the information limit the usefulness of the theorem presented above. At present such procedures, while they may theoretically offer broad prospects, are restricted by formal encoding procedures that depend upon the capacities of the instruments in which they are stored. Although such devices can handle quickly the logic of vast amounts of relatively simple information, they cannot match the flexibility and complexity of the human brain, still the prime instrument for managing the subtleties of most human communication.
