The Transmission Model of CommunicationDaniel ChandlerIntroductionHere I will outline and critique a particular, very well-known model ofcommunication developed by Shannon and Weaver (1949), as the prototypicalexample of a transmissive model of communication: a model which reducescommunication to a process of transmitting information. The underlyingmetaphor of communication as transmission underlies commonsense everydayusage but is in many ways misleading and repays critical attention.Shannon and Weavers model is one which is, in John Fiskes words, widelyaccepted as one of the main seeds out of which Communication Studies hasgrown (Fiske 1982: 6). Claude Shannon and Warren Weaver were not socialscientists but engineers working for Bell Telephone Labs in the United States.Their goal was to ensure the maximum efficiency of telephone cables and radiowaves. They developed a model of communication which was intended toassist in developing a mathematical theory of communication. Shannon andWeavers work proved valuable for communication engineers in dealing withsuch issues as the capacity of various communication channels in bits persecond. It contributed to computer science. It led to very useful work onredundancy in language. And in making information measurable it gave birthto the mathematical study of information theory. However, these directions arenot our concern here. The problem is that some commentators have claimedthat Shannon and Weavers model has a much wider application to humancommunication than a purely technical one.
C & Ws original model consisted of five elements: 1. An information source, which produces a message. 2. A transmitter, which encodes the message into signals 3. A channel, to which signals are adapted for transmission 4. A receiver, which decodes (reconstructs) the message from the signal. 5. A destination, where the message arrives.A sixth element, noise is a dysfunctional factor: any interference with themessage travelling along the channel (such as static on the telephone or radio)which may lead to the signal received being different from that sent.For the telephone the channel is a wire, the signal is an electrical current in it,and the transmitter and receiver are the telephone handsets. Noise wouldinclude crackling from the wire. In conversation, my mouth is the transmitter,the signal is the sound waves, and your ear is the receiver. Noise would includeany distraction you might experience as I speak.Although in Shannon and Weavers model a speaker and a listener wouldstrictly be the source and the destination rather than the transmitter and thereceiver, in discussions of the model the participants are commonly humanisedas the sender and the receiver. My critical comments will refer less specificallyto Shannon and Weavers model than to the general transmission model whichit reflects, where communication consists of a Sender passing a Message to aReceiver. So when I am discussing transmission models in general I too willrefer to the participants as the Sender and the Receiver.Shannon and Weavers transmission model is the best-known example of theinformational approach to communication. Although no seriouscommunication theorist would still accept it, it has also been the mostinfluential model of communication which has yet been developed, and itreflects a commonsense (if misleading) understanding of what communicationis. Lasswells verbal version of this model: Who says what in which channelto whom with what effect ? was reflected in subsequent research in humancommunication which was closely allied to behaviouristic approaches.Levels of problems in the analysis of communicationShannon and Weaver argued that there were three levels of problems ofcommunication:
o A The technical problem: how accurately can the message be transmitted? o B The semantic problem: how precisely is the meaning conveyed? o C The effectiveness problem: how effectively does the received meaning affect behaviour?Shannon and Weaver somewhat naively assumed that sorting out Level Aproblems would lead to improvements at the other levels.Although the concept of noise does make some allowance for the way inwhich messages may be distorted, this frames the issue in terms of incidentalinterference with the senders intentions rather than in terms of a central andpurposive process of interpretation. The concept reflects Shannon and Weaversconcern with accuracy and efficiency.Advantages of Shannon and Weavers modelParticular models are useful for some purposes and less useful for others. Likeany process of mediation a model foregrounds some features and backgroundsothers. The strengths of Shannon and Weavers model are its o simplicity, o generality, and o quantifiability.Such advantages made this model attractive to several academic disciplines. Italso drew serious academic attention to human communication andinformation theory, leading to further theory and research.Weaknesses of the transmission model of communicationThe transmission model is not merely a gross over-simplification but adangerously misleading misrepresentation of the nature of humancommunication. This is particularly important since it underlies thecommonsense understanding of what communication is. Whilst such usagemay be adequate for many everyday purposes, in the context of the study ofmedia and communication the concept needs critical reframing.
MetaphorsShannon and Weavers highly mechanistic model of communication can beseen as being based on a transport metaphor. James Carey (1989: 15) notes thatin the nineteenth century the movement of information was seen as basicallythe same as the transport of goods or people, both being described ascommunication. Carey argues that it is a view of communication that derivesfrom one of the most ancient of human dreams: the desire to increase the speedand effect of messages as they travel in space (ibid.) Writing always had to betransported to the reader, so in written communication the transport of letters,books and newspapers supported the notion of the transport of meaning fromwriter to readers. As Carey notes, The telegraph ended the identity but did notdestroy the metaphor (ibid.).Within the broad scope of transport I tend to see the model primarily asemploying a postal metaphor. It is as if communication consists of a sendersending a packet of information to a receiver, whereas I would insist thatcommunication is about meaning rather than information. One appallingconsequence of the postal metaphor for communication is the current referenceto delivering the curriculum in schools, as a consequence of which teachers aretreated as postal workers. But the influence of the transmission model iswidespread in our daily speech when we talk of conveying meaning, gettingthe idea across, transferring information, and so on. We have to be very alertindeed to avoid falling into the clutches of such transmissive metaphors.Michael Reddy (1979) has noted our extensive use in English of the conduitmetaphor in describing communicative acts. In this metaphor, The speakerputs ideas (objects) into words (containers) and sends them (along a conduit) toa hearer who takes the idea/objects out of the word/containers (Lakoff &Johnson 1980: 10). The assumptions the metaphor involves are that: o Language functions like a conduit, transferring thoughts bodily from one person to another; o in writing and speaking, people insert their thoughts or feelings into the words; o words accomplish the transfer by containing the thoughts or feelings and conveying them to others; o in listening or reading, people extract the thoughts and feelings once again from the words. (Reddy 1979: 290)
As Reddy notes, if this view of language were correct, learning would beeffortless and accurate. The problem with this view of language is that learningis seen as passive, with the learner simply taking in information (Bowers 1988:42). I prefer to suggest that there is no information in language, in books or inany medium per se. If language and books do contain something, this is onlywords rather than information. Information and meaning arises only in theprocess of listeners, readers or viewers actively making sense of what they hearor see. Meaning is not extracted, but constructed.In relation to mass communication rather than interpersonal communication,key metaphors associated with a transmission model are those of thehypodermic needle and of the bullet. In the context of mass communicationsuch metaphors are now largely used only as the targets of criticism byresearchers in the field.LinearityThe transmission model fixes and separates the roles of sender and receiver.But communication between two people involves simultaneous sending andreceiving (not only talking, but also body language and so on). In Shannonand Weavers model the source is seen as the active decision-maker whodetermines the meaning of the message; the destination is the passive target.It is a linear, one-way model, ascribing a secondary role to the receiver, who isseen as absorbing information. However, communication is not a one-waystreet. Even when we are simply listening to the radio, reading a book orwatching TV we are far more interpretively active than we normally realize.There was no provision in the original model for feedback (reaction from thereceiver). Feedback enables speakers to adjust their performance to the needsand responses of their audience. A feedback loop was added by later theorists,but the model remains linear.Content and meaningIn this model, even the nature of the content seems irrelevant, whereas thesubject, or the way in which the participants feel about it, can shape the processof communication. Insofar as content has any place (typically framed as themessage), transmission models tend to equate content and meaning, whereasthere may be varying degrees of divergence between the intended meaning andthe meanings generated by interpreters.
According to Erik Meeuwissen (e-mail 26/2/98) Shannon himself was wellaware of the fact that his theory did not address meaning. He offers thesesupportive quotations from Shannon and Weaver: The fundamental problem of communication is that of reproducing at one point either exactly or approximately a message selected at another point. Frequently the messages have meaning; that is they refer to or are correlated according to some system with certain physical or conceptual entities. These semantic aspects of communication are irrelevant to the engineering problem (Shannon 1948). The word information, in this theory, is used in a special sense that must not be confused with its ordinary usage. In particular, information must not be confused with meaning. In fact, two messages, one of which is heavily loaded with meaning and the other of which is pure nonsense, can be exactly equivalent, from the present viewpoint, as regards information. It is this, undoubtedly, that Shannon means when he says that the semantic aspects of communication are irrelevant to the engineering aspects. (Weaver 1949)Weaver also noted that the theory ...has so penetratingly cleared the air that one is now, perhaps for the first time, ready for a real theory of meaning. An engineering communication theory is just like a very proper and discreet girl accepting your telegram. She pays no attention to the meaning whether it be sad, or joyous, or embarrassing. But she must be prepared to deal with all that come to her desk (Weaver 1949).However, the important point here is that meaning-making is not central intransmission models. It is widely assumed that meaning is contained in themessage rather than in its interpretation. But there is no single, fixed meaningin any message. We bring varying attitudes, expectations and understandings tocommunicative situations. Even if the receiver sees or hears exactly the samemessage which the sender sent, the sense which the receiver makes of it may bequite different from the senders intention. The same message may representmultiple meanings. The word message is a sort of microcosm of the wholepostal metaphor, so Im not happy with even using that label.Transmission models treat decoding as a mirror image of encoding, allowing noroom for the receivers interpretative frames of reference. Where the message isrecorded in some form senders may well have little idea of who the receiversmay be (particularly, of course, in relation to mass communication). The
receiver need not simply accept, but may alternatively ignore or oppose amessage. We dont all necessarily have to accept messages which suggest that aparticular political programme is good for us.InstrumentalismThe transmission model is an instrumental model in that it treatscommunication as a means to a predetermined end. Perhaps this is the way inwhich some people experience communication. However, not allcommunication is intentional: people unintentionally communicate a great dealabout their attitudes simply through body language. And, although this ideawill sound daft to those whove never experienced it, when some of us writesomething, we sometimes find out what we want to say only after wevefinished writing about it.Some critics argue that this model is geared towards improving acommunicators ability to manipulate a receiver. Carey notes that the centre ofthis idea of communication is the transmission of signals or messages overdistance for the purposes of control... of distance and people (Carey 1989: 15).In an instrumental framework the process involved is intended to betransparent to the participants (nothing is intended to distract from the senderscommunicative goal). Such a conception is as fundamental to the rhetoric ofscience as it is alien to that of art. Perfectly transparent communication isimpossible.ContextNor is there any mention in the transmission model of the importanceof context: situational, social, institutional, political, cultural, historical.Meaning cannot be independent of such contexts. Whilst recorded texts (suchas letters in relation to interpersonal communication and newspapers, films,radio and television programmes in relation to mass communication) allowtexts to be physically separated from their contexts of production, this is not tosay that meaning can be context-free. Whilst it is true that meaning is notwholly determined by contexts of production or reception (texts do not meansimply what either their producers or their interpreters choose for them tomean), meanings may nevertheless be radically inflected by particular contextsof writing and reading in space and time. The same text can be interpretedquite differently within different contexts.
Social contexts have a key influence on what are perceived as appropriateforms, styles and contents. Regardingsituational context, it makes a lot ofdifference if the sender is an opinionated taxi-driver who drives aggressively,and the receiver is a passenger in the back seat whose primary concern is toarrive at the destination in one piece.Relationships and purposesIn the transmission model the participants are treated as isolated individuals.Contemporary communication theorists treat communication as a shared socialsystem. We are all social beings, and our communicative acts cannot be said torepresent the expression of purely individual thoughts and feelings. Suchthoughts and feelings are socio-culturally patterned. Even what we call ourlanguage isnt our own: we are born into it; we cant change the rules. Wordshave connotations which we dont choose for them. An emphasis on creativeindividuality is itself a culturally-shaped myth which had a historically modernorigin in Western Europe.Transmission models of communication reduce human communication to thetransmission of messages, whereas, as the linguists tell us, there is more tocommunication than this. They refer, for instance, to phatic communication,which is a way of maintaining relationships. In Britain, talking about theweather is far more a matter of phatic communication than of transmittinginformation.No allowance is made in the transmission model for differing purposes. Thesame TV images of a football match would have very different meanings forthe fans of opposing sides.In models such as Shannon and Weavers no allowance is made forrelationships between people as communicators (e.g. differences in power). Weframe what is said differently according to the roles in which we communicate.If a friend asks you later what you thought of this lecture you are likely toanswer in a somewhat different way from the way you might answer the samequestion from the undergraduate course director in his office. The interview is avery good example of the unequal power relationship in a communicativesituation.People in society do not all have the same social roles or the same rights. Andnot all meanings are accorded equal value. It makes a difference whether the
participants are of the same social class, gender, broad age group or profession.We need only think of whose meanings prevail in the doctors surgery. And,more broadly, we all know that certain voices carry more authority thanothers, and that in some contexts, children are to be seen and not heard. Thedominant directionality involved in communication cannot be fixed in a modelbut must be related to the situational distribution of power.TimeFurthermore, Shannon and Weavers model makes no allowance for dynamicchange over time. People dont remain frozen in the same roles andrelationships, with the same purposes. Even within the course of a singleconversation, such relationships may continuously shift. Also, adopting a morehistorical perspective, however stable the text may seem to be, the ways inwhich a recorded text may be interpreted depends also on circumstances at thattime of its interpretation.MediumFinally, the model is indifferent to the nature of the medium. And yet whether youspeak directly to, write to, or phone a lover, for instance, can have majorimplications for the meaning of your communication. There are widespreadsocial conventions about the use of one medium rather than another for specificpurposes. People also differ in their personal attitudes to the use of particularmedia (e.g. word processed Christmas circulars from friends!).Furthermore, each medium has technological features which make it easier touse for some purposes than for others. Some media lend themselves to directfeedback more than others. The medium can affect both the form and thecontent of a message. The medium is therefore not simply neutral in theprocess of communication.ConclusionIn short, the transmissive model is of little direct value to social scienceresearch into human communication, and its endurance in popular discussion is
a real liability. Its reductive influence has implications not only for thecommonsense understanding of communication in general, but also for specificforms of communication such as speaking and listening, writing and reading,watching television and so on. In education, it represents a similarlytransmissive model of teaching and learning. And in perception in general, itreflects the naive realist notion that meanings exist in the world awaiting onlydecoding by the passive spectator. In all these contexts, such a modelunderestimates the creativity of the act of interpretation.Alternatives to transmissive models of communication are normally describedas constructivist: such perspectives acknowledge that meanings are activelyconstructed by both initiators and interpreters rather than simply transmitted.However, you will find no single, widely-accepted constructivist model ofcommunication in a form like that of Shannon and Weavers block diagram.This is partly because those who approach communication from theconstructivist perspective often reject the very idea of attempting to produce aformal model of communication. Where such models are offered, they stressthe centrality of the act of making meaning and the importance of the socio-cultural context.References o Bowers, C. A. (1988): The Cultural Dimensions of Educational Computing: Understanding the Non-Neutrality of Technology. New York: Teachers College Press [generally very useful, though difficult, and cited here only for commentary on Michael Reddy on pages 42-4] o Carey, James (1989): Communication as Culture. New York: Routledge (Chapter 1, A Cultural Approach to Communication) o Ellis, Russell & Ann McClintock (1990): If You Take My Meaning: Theory into Practice in Human Communication. London: Arnold (Chapter 5, (Communication Models) o Fiske, John (1982): Introduction to Communication Studies. London: Routledge (Chapter 1, Communication Theory is a good introduction to this topic) o Kress, Gunther (1988): Communication and Culture. In Gunther Kress (Ed.): Communication and Culture.Kensington, NSW: New South Wales University Press o Lakoff, George & Mark Johnson (1980): Metaphors We Live By. Chicago: University of Chicago Press
o McQuail, Denis & Sven Windahl (1993): Communication Models for the Study of Mass Communication. London: Longman o Reddy, Michael J. (1979): The Conduit Metaphor: A Case of Frame Conflict in our Language about Language. In Andrew Ortony (Ed.): Metaphor and Thought. Cambridge: Cambridge University Press [for commentaries see: Bowers 1988: 38ff; Lakoff & Johnson 1980: 10- 12] o Shannon, Claude E (1948): A Mathematical Theory of Communication, Part I, Bell Systems Technical Journal, 27, pp. 379-423 o Shannon, Claude E. & Warren Weaver (1949): A Mathematical Model of Communication. Urbana, IL: University of Illinois Press o Smith, Frank (1983): Essays into Literacy. Portsmouth: Heinemann (Chapter 13, A Metaphor for Literacy - Creating Worlds or Shunting Information?) o Thwaites, Tony, Lloyd Davis & Warwick Mules (1994): Tools for Cultural Studies: An Introduction. South Melbourne: Macmillan (Chapter 1) o Weaver, Warren (1949): Recent Contributions to the Mathematical Theory of Communication. In Shannon & Weaver op.citSee also any general reference books on communication.Daniel ChandlerUWA 1994