Excerpts from Daniel Chandler, “The Transmission Model of Communication” (1995)
The transmission model fixes and separates the roles of ‘sender’ and ‘receiver’. But communication between two people involves simultaneous ‘sending’ and ‘receiving’ (not only talking, but also ‘body language’ and so on). In Shannon and Weaver’s model the source is seen as the active decision-maker who determines 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 is seen as absorbing information. However, communication is not a one-way street. Even when we are simply listening to the radio, reading a book or watching TV we are far more interpretively active than we normally realize.
There was no provision in the original model for feedback (reaction from the receiver). Feedback enables speakers to adjust their performance to the needs and responses of their audience. A ‘feedback loop’ was added by later theorists, but the model remains linear.
 Transmission models treat decoding as a mirror image of encoding, allowing no room for the receiver’s interpretative frames of reference. Where the message is recorded in some form ‘senders’ may well have little idea of who the ‘receivers’ may be (particularly, of course, in relation to mass communication). The receiver need not simply accept, but may alternatively ignore or oppose a message. We don’t all necessarily have to accept messages which suggest that a particular political programme is good for us.
 In the transmission model the participants are treated as isolated individuals. Contemporary communication theorists treat communication as a shared social system. We are all social beings, and our communicative acts cannot be said to represent the expression of purely individual thoughts and feelings. Such thoughts and feelings are socio-culturally patterned.
 In models such as Shannon and Weaver’s no allowance is made for relationships between people as communicators (e.g. differences in power). We frame 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 to answer in a somewhat different way from the way you might answer the same question from the undergraduate course director in his office. The interview is a very good example of the unequal power relationship in a communicative situation.
People in society do not all have the same social roles or the same rights. And not 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 doctor’s surgery. And, more broadly, we all know that certain voices ‘carry more authority’ than others, and that in some contexts, ‘children are to be seen and not heard’. The dominant directionality involved in communication cannot be fixed in a model but must be related to the situational distribution of power.
 Finally, the model is indifferent to the nature of the medium. And yet whether you speak directly to, write to, or phone a lover, for instance, can have major implications for the meaning of your communication. There are widespread social conventions about the use of one medium rather than another for specific purposes. People also differ in their personal attitudes to the use of particular media (e.g. word processed Christmas circulars from friends!).
Furthermore, each medium has technological features which make it easier to use for some purposes than for others. Some media lend themselves to direct feedback more than others. The medium can affect both the form and the content of a message. The medium is therefore not simply ‘neutral ‘ in the process of communication.
In short, the transmissive model is of little direct value to social science research into human communication, and its endurance in popular discussion is a real liability. Its reductive influence has implications not only for the commonsense understanding of communication in general, but also for specific forms of communication such as speaking and listening, writing and reading, watching television and so on. In education, it represents a similarly transmissive model of teaching and learning. And in perception in general, it reflects the naive ‘realist’ notion that meanings exist in the world awaiting only decoding by the passive spectator. In all these contexts, such a model underestimates the creativity of the act of interpretation.
Alternatives to transmissive models of communication are normally described as constructivist: such perspectives acknowledge that meanings are actively constructed by both initiators and interpreters rather than simply ‘transmitted’. However, you will find no single, widely-accepted constructivist model of communication in a form like that of Shannon and Weaver’s block diagram. This is partly because those who approach communication from the constructivist perspective often reject the very idea of attempting to produce a formal model of communication. Where such models are offered, they stress the centrality of the act of making meaning and the importance of the socio-cultural context.