Preliminary Class Business

• What to watch for in future readings on history of computing:
  
  
  • main technical developments
    
    
  • conceptual and logical principles (e.g., von Neumann computer, stored program computer)
    
    
  • 50s culture, 70s culture
    
    
  • NCSA Beginner's Guide to HTML

Media and Communication

Where we are in the course:

Information Paradigm	Signature Technologies	Logical Architecture	Peak Epoch (Period of Monopolistic or Cartel Dominance)
Information as Mass Media	Radio, Photography, Film, TV, Magazines	Broadcast Model	1920s-1970s
Information as Communication	Telegraphy, Telephony, Radio	Transmission Model	1940s-70s (ATT breakup in 1984)
Information as Computing I: Age of the Mainframe	Mainframes and Minicomputers, Databases	Centralized information services	1950s-1970s (1969-82 anti-trust suit against IBM)
Information as Computing II: Age of Distributed Computing	PC's Networks (LAN's, WAN's) The "Software Revolution" Graphical User Interface (GUI) WWW	Client/Server Architecture Packetization	1980s-2000s (1998-2002 anti-trust suit against MS)

The fundamental relationship between "media" and "communication"

Consider the notion of the "ancestral environment" of information:

How does one share information across time and space?

Communications and media are two sides of the same coin-- humans (unlike animals) communicate through media

Co-evolution of 20th-C. Media and Communication

• In the middle of the 20th century, the "media" and "communications revolutions"were parallel events that radically increased the transportability and autonomy of media-as-communications
  
  
• Mediated communications "thickened" into an increasingly complex self-regulating system removed from the "ancestral" natural and social systems of human information:
  
               Sender Receiver
  
     Sender Receiver
  
  

  Marshall McLuhan: "the medium is the message" (the medium is its own message separate from the meaning of the message)

  
  

  Claude Shannon: the communication system (bits in the channel) is the message "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"

  
  

The Communications Revolution: "The Mathematical Theory of Communication"

• Today, we look at the communications revolution in the mid-20th century, specifically the "mathematical theory of communication" (or "information theory") as it was invented by Claude Shannon and Warren Weaver of Bell Labs
  
  
• The theory revolutionized telecommunications and information processing immediately after WW II (and epitomized the epoch of problems in transmission, cryptography, and ultimately cybernetic technology that the war focused attention upon) (cf., Vannevar Bush's "As We May Think," 1945)
  
  
• It also had a cultural influence well beyond its original technological context. Examples: Thomas Pynchon on entropy, or A. J. Greimas on narratology. From A. J. Greimas, Structural Semantics:
                    

Claude Shannon's "Mathematical Theory of Communication" (1948): Some Basic Principles

The second paragraph of Shannon's essay:

Excerpts from Warren Weaver, "Recent Contributions to the Mathematical Theory of Communication" (1949)

The word communication will be used here in a very broad sense to include all of the procedures by which one mind may affect another. This, of course, involves not only written and oral speech, but also music, the pictorial arts, the theatre, the ballet, and in fact all human behavior. In some connections it may be desirable to use a still broader definition of communication, namely, one which would include the procedures by means of which one mechanism (say automatic equipment to track an airplane and to compute its probable future positions) affects another mechanism (say a guided missile chasing this airplane). (p. 95)

        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. (p. 99)

The quantity which uniquely meets the natural requirements that one sets up for "information" turns out to be exactly that which is known in thermodynamics as entropy. [ . . . ] Thus when one meets the concept of entropy in communication theory, he has a right to be rather excited—a right to suspect that one has hold of something that may turn out to be basic and important. That information be measured by entropy is, after all, natural when we remember that information, in communication theory, is associated with the amount of freedom of choice we have in constructing messages. Thus for a communication source one can say, just as he would also say it of a thermodynamic ensemble, "This situation is highly organized, it is not characterized by a large degree of randomness or of choice—that is to say, the information (or the entropy) is low." p. 103)

Remember that the entropy (or information) associated with the process which generates messages or signals is determined by the statistical character of the process—by the various probabilities for arriving at message situations and for choosing, when in those situations the next symbols. The statistical nature of messages is entirely determined by the character of the source. But the statistical character of the signal as actually transmitted by a channel, and hence the entropy in the channel, is determined both by what one attempts to feed into the channel and by the capabilities of the channel to handle different signal situations. [ . . . ] The best transmitter, in fact, is that which codes the message in such a way that the signal has just those optimum statistical characteristics which are best suited to the channel to be used—which in fact maximize the signal (or one may say, the channel) entropy and make it equal to the capacity C of the channel. p. 108)

How does noise affect information? Information is, we must steadily remember, a measure of one's freedom of choice in selecting a message. The greater this freedom of choice, and hence the greater the information, the greater is the uncertainty that the message actually selected is some particular one. Thus greater freedom of choice, greater uncertainty, greater information go hand in hand.
        If noise is introduced, then the received message contains certain distortions, certain errors, certain extraneous material, that would certainly lead one to say that the received message exhibits, because of the effects of noise, an increased uncertainty. But if the uncertainty is increased, the information is increased, and this sounds as though the noise were beneficial!
        [ . . . ] It is thus clear where the joker is in saying that the received signal has more information. Some of this information is spurious and undesirable and has been introduced via the noise. To get the useful information in the received signal we must subtract out this spurious portion. (pp. 108-109)

        The obvious first remark, and indeed the remark that carries the major burden of the argument, is that the mathematical theory is exceedingly general in its scope, fundamental in the problems it treats, and of classic simplicity and power in the results it reaches.
        This is a theory so general that one does not need to say what kinds of symbols are being considered—whether written letters or words, or musical notes, or spoken words, or symphonic music,or pictures. The theory is deep enough so that the relationships it reveals indiscriminately apply to all these and to other forms of communication. This means, of course, that the theory is sufficiently imaginatively motivated so that it is dealing with the real inner core of the communication problem—with those basic relationships which hold in general, no matter what special form the actual case may take. (pp. 114-15)

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. (p. 116)

The appearance of entropy in the theory, as was remarked earlier, is surely most interesting and significant. Eddington has already been quoted in this connection, but there is another passage in "The Nature of the Physical World" which seems particularly apt and suggestive:

        Suppose that we were asked to arrange the following in two categories—distance, mass, electric force, entropy, beauty, melody.
         I think there are the strongest grounds for placing entropy alongside beauty and melody, and not with the first three. Entropy is only found when the parts are viewed in association, and it is by viewing or hearing the parts in association that beauty and melody are discerned. All three are features of arrangement. It is a pregnant thought that one of these three associates should be able to figure as a commonplace quantity of science. The reason why this stranger can pass itself off among the aborigines of the physical world is that it is able to speak their language, viz., the language of arithmetic.

        I feel sure that Eddington would have been willing to include the word meaning along with beauty and melody; and I suspect he would have been thrilled to see, in this theory, that entropy not only speaks the language of arithmetic; it also speaks the language of language. (p. 117)

Excerpts from Daniel Chandler, "The Transmission Model of Communication" (1995)

[1] Information and meaning arises only in the process of listeners, readers or viewers actively making sense of what they hear or see. Meaning is not 'extracted', but constructed.

[2] Linearity

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.

[3] 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.

[4] 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.

[5] 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.

[6] 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.

[7] Conclusion

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.

Definitions of "PCM" and "PPM" (contrasted with "PAM")

References

• Albert Borgmann, Holding On to Reality: The Nature of Information at the Turn of the Millennium (Chicago: Univ. of Chicago Press, 1999)
• Jean Baudrillard, Simulations, trans. Paul Foss, Paul Patton, and Philip Beitchman (New York: Semiotext(e), 1983)
• James R. Beniger, The Control Revolution: Technological and Economic Origins of the Information Society (Cambridge, Mass.: Harvard Univ. Press, 1986)
• Daniel Chandler, "The Transmission Model of Communication" (1995)
• Clifford Geertz, The Interpretation of Cultures (New York: Basic, 1973), Chap. 1, "Thick Description: Toward an Intepretive Theory of Culture," Chap. 15, "Deep Play: Notes on the Balinese Cockfight"
• A. J. Greimas, Structural Semantics: An Attempt at a Method, trans. Daniele McDowall et. al. (Lincoln: Univ. of Nebraska Press, 1983)
  
  
• On cryptography and early computing during WW II:
  • Simon Singh, The Code Book: The Evolution of Secrecy from Mary, Queen of Scots to Quantum Cryptography (New York: Doubleday, 1999)
• Neal Stephenson, Cryptonomicon (New York: Avon, 1999)