 |
 |
 |
Introductory
models & basic concepts: Shannon-Weaver
|
|||
| Introductory
models & basic concepts: Shannon-Weaver |
If you have looked through the examples of typical everyday forms of communication, you will have noticed that some of the examples refer to less immediate methods of communication than face-to-face interaction, e.g. using the radio, newspapers or the telephone. In these cases, technology is introduced.
When, for instance, the telephone is used, you speak, the phone turns the sound waves into electrical impulses and those electrical impulses are turned back into sound waves by the phone at the other end of the line.
Claude Shannon and Warren Weaver produced a general model of communication:
This is now known after them as the Shannon-Weaver Model. Although they were principally concerned with communication technology, their model has become one which is frequently introduced to students of human communication early in their study. However, despite the fact that it is frequently used early in the study of human communication, I think it's worth bearing in mind that information theory, or statistical communication theory was initially developed to separate noise from information carrying signals. That involved breaking down an information system into sub-systems so as to evaluate the efficiency of various communication channels and codes. You might ask yourself how viable the transfer of Shannon's insights from information theory to human communication is likely to be. The concepts of information theory and cybernetics are essentially mathematical and are intended to be applied to technical problems under clearly defined conditions. After you've read this section, which, I think, is a reasonable attempt to loosely apply Shannon's ideas to human communication, ask yourself whether you feel enlightened.
The Shannon-Weaver Model (1947) proposes that all communication must include six elements:
The emphasis here is very much on the transmission and reception of information. 'Information' is understood rather differently from the way you and I would normally use the term, as well. This model is often referred to as an 'information model' of communication. (But you don't need to worry about that if you're just starting.)
Apart from its obvious technological bias, a drawback from our point of view is the model's obvious linearity. It looks at communication as a one-way process. That is remedied by the addition of the feedback loop which you can see in the developed version of the model:
A further drawback with this kind of model is that the message is seen
as relatively unproblematic. It's fine for discussing the transformation
of 'information', which might be, say &Hui9%/?PLM, but, when we try
to apply the model to communication, problems arise with the assumption
that meanings are somehow contained within the message.
All human communication has some source (information source
in Shannon's terminology), some person or group of persons with a given
purpose, a reason for engaging in communication. You'll also find the terms
transmitter
and communicator used.
For a fuller discussion of 'source', see The
Lasswell Formula
When you communicate, you have a particular purpose in mind:
It's fairly easy to think in terms of source and encoder when you are talking on the phone (transmitter in Shannon's terminology). You are the source of the message and the 'phone is the encoder which does the job of turning your sounds into electrical impulses. The distinction is not quite so obvious when you think of yourself communicating face-to-face.
In person-to-person communication, the encoding process is performed by the motor skills of the source - vocal mechanisms (lip and tongue movements, the vocal cords, the lungs, face muscles etc.), muscles in the hand and so on. Some people's encoding systems are not as efficient as others'. So, for example, a disabled person might not be able to control movement of their limbs and so find it difficult to encode the intended non-verbal messages or they may communicate unintended messages. A person who has suffered throat cancer may have had their vocal cords removed. They can encode their messages verbally using an artificial aid, but much of the non-verbal messages most of us send via pitch, intonation, volume and so on cannot be encoded.
Shannon was not particularly concerned with the communication of meanings.
In fact, it is Wilbur Schramm's model of 1954 which places greater
emphasis on the processes of encoding and decoding. The inclusion of the
encoding and decoding processes is very helpful to us since it draws our
attention to the possibility of a mismatch between the operation of the
encoding and decoding devices, which can cause semantic
noise to be set up. With good reason, the source of the message
may wonder whether the picture in the receiver's head will bear any resemblance
to what's in his/her own. Schramm went on to introduce the notion of a
'field of experience', which shows a much greater awareness of the subtleties
involved in human-to-human communication, drawing our attention to the
numerous shared socio-cultural factors which are necessary for successful
communication to take place (see David Berlo's S-M-C-R model).
The message of course is what communication is all about. Whatever is communicated is the message. Denis McQuail (1975) in his book Communication writes that the simplest way of regarding human communication is 'to consider it as the sending from one person to another of meaningful messages'.
The Shannon-Weaver Model, in common with many others separates the message from other components of the process of communication. In reality, though, you can only reasonably examine the message within the context of all the other interlinked elements. Whenever we are in contact with other people we and they are involved in sending and receiving messages. The crucial question for Communication Studies is: to what extent does the message received correspond to the message transmitted? That's where all the other factors in the communication process come into play.
The Shannon-Weaver model and others like it tends to portray the message as a relatively uncomplicated matter. Note that this is not a criticism of Shannon since meanings were simply not his concern:
Frequently the messages have meaning, that is they refer to or are correlated according to some system with certain physical or conceptual entities. These considerations are irrelevant to the engineering problem.This was particularly emphasized in Warren Weaver's introduction to Shannon's paper:
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.It may however be a criticism of the application of Shannon's model to the more general area of human-to-human communication. Meanings are assumed to be somehow contained within the signs used in the message and the receiver can, as it were, take them out again. Matters such as the social context in which the message is transmitted, the assumptions made by source and receiver, their past experiences and so on are simply disregarded. In this respect, models which incorporate such factors are probably more revealing of the complexity of the communication process. (See, for example, the sections on Berlo's SMCR model or Maletzke's model of mass communication)
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.
You tap on a membrane suspended above a steadily flowing jet of water. The air under the membrane causes slight deflections in the jet of water. A laser is aimed at a receiver. The jet of water flows through the laser beam, deflecting it from its target. Every time the water jet is deflected by the movement of the air, the laser beam hits its target. The laser receiver is connected to a computer which takes each 'hit' and turns it into a 1 and each miss and turns it into a 0. The computer sends these etc. etc......
You get the idea: the air waves, the jet of water and so on are all
channels. The words channel and medium are often used interchangeably,
if slightly inaccurately. The choice (a pretty stupid one above) of the
appropriate channel is a vitally important choice in communication.
Shannon is generally considered to have been primarily concerned with physical (or 'mechanical' or 'engineering') noise in the channel, i.e. unexplained variation in a communication channel or random error in the transmission of information. Everyday examples of physical noise are:
However, it is possible for a message to be distorted by channel overload. Channel overload is not due to any noise source, but rather to the channel capacity being exceeded. You may come across that at a party where you are holding a conversation amidst lots of others going on around you or, perhaps, in a Communication lesson where everyone has split into smallgroups for discussion or simulations.
Shannon and Weaver were primarily involved with the investigation of technological communication. Their model is perhaps more accurately referred to as a model of information theory (rather than communication theory). Consequently, their main concern was with the kind of physical (or mechanical) noise discussed above.
Although physical noise and how to avoid it is certainly a major concern of scholars of communication, the Shannon and Weaver model turns out to be particularly suggestive in the study of human communication because of its introduction of a decoding device and an encoding device. The possibility of a mismatch between the two devices raises a number of interesting questions. In technological communication: I give you a PC disk and you stick it into a Mac - the Mac can't decode it; I give you an American NTSC video tape and you stick it into a European PAL video recorder - the recorder won't decode it. Transfer this notion of a mismatch between the encoding and decoding devices to the study of human communication and you're looking at what is normally referred to as semantic noise. That concept then leads us on to the study of social class, cultural background, experience, attitudes, beliefs and a whole range of other factors which can introduce noise into communication.
It might be worth mentioning here, especially in connexion with the
reference to the linearity of the Shannon-Weaver model, that some workers
in the newly developing science of complexity
have pointed to a fundamental twin flaw in our science since Newton (I
am greatly simplifying here), namely that science has been concerned to
understand the world using linear models and has also been concerned to
discount as 'experimental noise' anything which might hinder the application
of a linear model. Complexity theorists point out that when you add the
noise into the system, you generally end up with something non-linear,
complex, unpredictable.
Semantic noise is not as easy to deal with as physical noise. It might not be an exaggeration to say that the very essence of the study of communication is to find ways of avoiding semantic noise. Semantic noise is difficult to define. It may be related to people's knowledge level, their communication skills, their experience, their prejudices and so on. There is more detailed discussion of those factors in Berlo's SMCR Model.
Examples of semantic noise would include:
Distraction:
You are physically very attracted to the person who is talking to you.
As a result, your attention is directed to their deep blue eyes rather
than what they are saying. There is no physical noise which prevents the
message from reaching you. You hear it, but you don't decode it. Equally,
your attention could be distracted by the other person's peculiar tics
and so on. Or think of when you watched the TV news: the reporter was standing
outside No.10 Downing Street, but behind him the policeman outside the
door was picking his nose. As soon as the report's over you realise you
haven't a clue what it was about.
Differences
in the use of the code: The other person is waffling on in Aramaic
about fishes. You don't understand. There is nothing which physically prevents
the elements of the message from reaching you, you simply can't understand
it.
Emphasising
the wrong part of the message: Maybe you can think of an advertising
campaign which has been so successful with some new style or gimmick that
everyone is talking about it. However, no one has actually noticed what
product is being advertised.
Attitude
towards the sender: You're talking to someone a lot older than you.
On the basis of their age, you make a lot of assumptions about the kind
of code appropriate to them - and the conversation goes wrong because they
were the wrong assumptions.
Just as a source needs an encoder to translate her purposes into a message, so the receiver needs a decoder to retranslate. The decoder (receiver in Shannon's paper) is an interesting and very useful development over, say, the Lasswell Formula.
If you take a look at our discussion of the receiver, you'll see that we considered how, for example, a blind person would not have the equipment to receive whatever non-verbal messages you send in the visual channel.
The notion of a decoder reminds us that it is quite possible for a person to have all the equipment required to receive the messages you send (all five senses, any necessary technology and so on) and yet be unable to decode your messages.
An obvious example would be:
You can see it. You probably guess that it's a language, maybe eventhat it's Arabic. You probably don't understand it, though. In fact, it is Arabic and it does mean (but nothing very interesting). My message, encoded to you in that short sentence, cannot be decoded by you. You have the appropriate receiving equipment, but no decoder. You don't understand the code.
Can you think of where you might come across a similar inability to decode where the English language is concerned? Suppose you've been reading around Communication Studies and have come across a reference to the philosopher Immanuel Kant. So you ask your teacher about him. She replies, "Well, the Critique of Pure Reason is essentially all about answering the question: how are synthetic judgements a priori possible?" Eh? You probably have a meaning for every one of those words, except perhaps 'a priori'. You might perhaps guess that she is using the title of one of Kant's works in her answer. But the statement is incomprehensible unless you know the technical jargon of philosophy. You can't decode the message - and your teacher is a pretty lousy teacher for having failed to predict your inability to decode it (or for having accurately predicted your inability and usingit as an excuse to show off!).
Those two examples may seem pretty obvious and also rather unusual.
Indeed, they are, but they do serve to illustrate how communication breakdown
can occur because we make the false assumption that receivers decode messages
in the same way we do, that they use the code in the same way. There's
a whole host of reasons why they won't - age differences, class differences,
cultural differences and so on (dealt with more thoroughly in Berlo's
SMCR Model).
For communication to occur, there must be somebody at the other end of the channel. This person or persons can be called the receiver. To put it in Shannon's terms, information transmitters and receivers must be similar systems. If they are not, communication cannot occur. (Actually Shannon used the term destination, reserving the term receiver for what we have called decoder. However, I think the terminology I have been using is more common in the broader understanding of 'communication theory' as distinct from Shannon's information theory.)
What that probably meant as far as he was concerned was that you need
a telephone at one end and a telephone at the other, not a telephone connected
to a radio. In rather more obviously human terms, the receiver needs to
have the equipment to receive the message. A totally blind person has the
mental equipment to decode your gestures, but no system for receiving messages
in the visual channel. So, your non-verbal messages are not received and
you're wasting your energy. See also the Lasswell
Formula for a more detailed discussion of 'receiver'.
Feedback is a vital part of communication. When we are talking to someone over the phone, if they don't give us the occasional 'mmmm', 'aaah', 'yes, I see' and so on, it can be very disconcerting. .This lack of feedback explains why most of us don't like ansaphones. In face-to-face communication, we get feedback in the visual channel as well - head nods, smiles, frowns, changes in posture and orientation, gaze and so on. Advertisers need feedback which they get in the form of market research from institutions like Gallup. How else would they know if their ads are on the right track? Broadcasters need feedback which they get from BARB's ratings. Politicians need feedback which they get from public opinion polls and so on.
Why do people often have difficulty when using computers, when they find it perfectly easy to drive a car? You'd think it should be easier to operate a computer - after all there are only a few keys and a mouse, as against levers, pedals and a steering wheel. A computer's not likely to kill you, either. It could be due to the lack of feedback - in a car, you've the sound of the engine, the speed of the landscape rushing past, the force of gravity. Feedback is coming at you through sight, hearing and touch -overdo it and it might come through smell as well! With a computer, there's very little of that.
Some years ago, our students used to play games on College computers during the lunch hour. Occasionally - if we held a lunchtime meeting, say - we would have to ask them to turn the sound off. It was amazing to see how their scores plummeted when that single channel of feedback was removed. Xerox at the Palo Alto research Centre (PARC) have been researching for years how to provide more feedback - for example, when you save a file to your hard disk, there might be a clanging noise and the more echo there is the emptier your hard disk is. You might at the moment be using a 'clicky' keyboard. There's no very good reason why a modern keyboard should make a constant clatter, but I'm used to using one at home and find it quite difficult to use keyboards which deprive me of that feedback.
Feedback is defined by the father of cybernetics, Norbert Wiener, as follows:
In its simplest form the feedback principle means that a behaviour is tested with reference to its result and success or failure of this result influences the future behaviour
The
Lasswell Formula
The
Osgood and Schramm Model
Gerbner's
Model
For further information, you may wish to consult the following websites:
Lucent
Technologies' excellent website with very clear explanations
Bell
Laboratories, where you can download a copy of Shannon's paper
Information
Theory Society Web Page
Entropy
in Information and Coding Theory
|