Communication Models

Communication theory models offer a convenient way to think about communication, providing a graphical checklist which one can use to create anything from a speech to a major advertising campaign. Formal communication theory (rhetorical theory) goes back 2500 years ago to Classical Greece when Plato, Aristotle, and the Sophists were speech teachers. (See my chapter on Classical Rhetoric for a more detailed account.) The Greek tradition was continued and improved upon by the Romans, after which it remained static until the twentieth century. Indeed, Classical Rhetoric was and still is being taught today. However, as a result of the proliferation of mass communications via radio, movies, and television, and of empirical scie ntific methods, communication theory changed in the latter part of the twentieth century. The main impetus was the need for propaganda techniques and to persuade troops to fight during WWI and WWII. Enter the sociologists.


Harold Lasswell produced Propaganda and the War1 in 1927. Later, Carl Hovland and his group of sociologists from Yale published an important book2 in 1949 describing the experiments they conducted on Army troops during the war. At about the same time Lasswell 3 < /SUP> introduced an important model, elements of which survive in more developed modern models.
	Says What
	In Which Channel
	To Whom
	To What Effect

As we will see, Lasswell's communication model is similar to the other models we will discuss. The "Who" is the "Source;" "Says What", the message; and "To Whom", the destination. Communications have a source who communicates a message through a channel o r medium to a destination (audience) that, hopefully, creates the desired effect. Claude Shannon's model is similar, but more graphical.

Shannon & Weaver's Mathematical Model (1949)

Shannon was a mathematician, not a sociologist; so his thinking, although similar, is a departure. The Shannon & Weaver model measures the accuracy of message transmission in a given communication system. Since Shannon did his research on informat ion theory for Bell Labs, it is no wonder that his model is based on a telephony analogy. Imagine that you make a telephone call to someone in another country ,that the person's first language whom you are calling is not English, and that you can be on t he line for only three minutes. According to the model, you are the information source. The telephone transmitter is the encoder; the telephone wire is the channel; the telephone receiver is the decoder, and the person whom you are calling is the receiver. Noise can be cross-talk and static on the line. The channel is limited to sound, and a narrow range of sound at that. The person receiving the message may decode it differently because he or she doesn't understand English well. Clearly, the more we maximize the amount of information sent over the line the better the communication. Note, for example, that many people do not like the idea of using a telephone that also sends images of them talking because the two together send too much infor mation. A salesperson does not want the boss back at the home office seeing him or her with a hangover from the night before.

Shannon did not equate information with meaning. For him, "Gamboling on the gumbo with the gambits all in gear," contained as much information as "All the world's a stage; And all the men and women merely players." For Shannon, information is the opportunity to reduce uncertainy. Information is the opposite of entropy. Entropy is disorder, randomness, or uncertainty. In a convoluted way, what we think of as more information can be, according to Shannon, less information because it results in uncertainty. As you know, the more you learn in college, the more you learn that there is more to know. The more uncertain you become. Where you once had simple answers for questions, you now have compl ex questions for answers. We might call all of this other information noise. Basically, noise is irrelevant information. It clogs the channel, changes the coding, etc. The conservative columnist and presidential candidate Pat Buchannan is an expert at creating noise to block the channel. When he argues with someone, he waits until the other person is about to make his or her main point, and then he interupts by asking a question that leads the conversation in another direction.

According to Shannon, we can overcome channel noise by using redundancy. In fact that is how portable CD players work. They go back over the information to check for errors. Advertisers use reduncancy, placing ads over and over, until they are atten ded to and remembered. Lecturers learn to repeat their main points in at least three different ways.

Limitations of the model

  1. Model deals only with mechanistic representation of communication.
  2. Does not deal with meaning, content, substance.
  3. Comm process is linear, no feedback in original.

For more on Shannon's Information Theory, click here.

McGuire's Model

William McGuire's4 adds a second dimension to his model. Instead of having only a X axis with Source, Message, Channel, and Receiver which he calls "input factors", he adds a Y axis comprised of Attention, Liking,Comprehension , Yielding, Remembering, and Action, which he calls "output factors." He actually had more output factors; however I've reduced them. In addition, as we shall see in another lecture, the output factors resemble steps in Monroe' s Motivated Sequence. Since McGuire combines the traditional S-M-C-R unidimensional model with factors on the Y axis, we have a more sophisticated way of thinking about and analyzing communication. In fact his two dimensional matrix is useful for anal yzing the effectiveness of persuasive communication both before and after the fact.


The computer, with its hypertext capability, allows us to read text in a different, nonlinear way. To continue reading this lecture, you should double click on the appropriate "hot text" (underlined and colored text) in the matrix. You can begin by double clicking on the word "Source" in the matrix.

< TD>.
SourceMessage Channel Receiver
Attention . . . . .
Liking . . . . .
Comprehension . . . . .
Yielding . . . .
Remembering . . . . .
Action . . . . .
< /CENTER> 1Harold Lasswell (1927). Propaganda Technique in the World War, Peter Smith.

2 Carl Hovland, et al. (1949). Experiments in Mass Communication.Princeton University Press.

3Harold Lasswell (1948). "The Structure and Function of Communication in Society." In Lyman Bryson (ed.), The Communication of Ideas. Harper and Row.

4 William McGuire (1981). "Theoretical Foundations of Campaigns." In Ronald Rice and William Paisley (eds.), Public Communication Campaigns, Sage.

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© Robert Gwynne 1999