Communication Theory and Semiotics by yaofenji


									Communication Theory and

        Graphics 1
• information theory - Shannon and Weaver
• application to visual communication; process theory
• noise: redundancy, entropy
• limitations of process theory
• conclusion - process theory and semiotics .
Warren Weaver
• American scientist and mathematician
• director of the Division of Natural
  Sciences at the Rockefeller
  Foundation, 1932 - 1955
     influential in the application of science;
      genetics, agriculture, medicine and
      molecular engineering and many other

• early work on machine translation and
  mass communication - ‘tower block
• co-author with Shannon of The
  Mathematical Theory of
  Communication, published 1949 .
Claude Elwood Shannon
• American mathematician and
  electronics engineer
• 1937, aged 21, his Master’s thesis
  established mathematical basis of
  digital circuit design and hence the
  modern computer
• had varied interests
     created a mechanical mouse that could
      learn a maze
     invented a motorised pogo stick
     beat blackjack and roulette at casinos
      using game theory and computation
     applied his theories to the stock market
      and was very successful! .
Shannon and Weaver, 1949
• during WW2 Shannon joined Bell Telephone Labs
    worked on fire-control systems (anti-missile targeting) and

• met and worked with many great scientists;
    people involved with earliest satellites, signal theory, first digital
     computers, the inventors of the transistor
    became friends with Alan Turin, discussed cryptography with him

• treated the problems he encountered as the need to
  distinguish ‘signal’ from ‘noise’
    by considering the role of ‘data’ in contrast to ‘signal processing’ he
     founded the field of ‘information theory’
    hence laid the foundations of all modern communication .
Shannon and Weaver, 1949
• ‘The Mathematical Theory of Communication’
    based largely on the work Shannon had published previously
    Weaver added a philosophical context to the work, showing its wider
     applications, and used his influence to popularise it

• theory focuses on the best way for the sender to
  encode information before sending it
    realised that all communication, including human language, could be
     measured in the form of a rate of ‘bits per second’…
    …and that all ‘channels of communication’ had their own maximum
     capacity, also measured in bits per second
    considered the role of ‘noise’ in disrupting integrity of information
    limited channel capacity and noise lead to uncertainty…
    …developed the concept of ‘information entropy’ as a measure of
     uncertainty in a message .
Shannon and Weaver, 1949

Hazard warning:       Mandatory: Wear          Prohibited: Do not
Corrosive materials   protective clothing      touch

• what limits the capacity of the ‘channel’?
• where might noise be introduced between sender and
process theory
• Shannon and Weaver’s contribution has been applied
  to many areas
      communications systems
      computer science
      linguistics
      cognitive science
      sociology
      media studies
      critical theory
      marketing and advertising

• if graphic design is concerned with ‘effective visual
  communication’ then information theory may help us
  analyse and discuss our work; ‘process theory’…
process theory
• all communication can be considered as a process in
  which message follows path from sender to receiver

     source     transmitter           receiver   destination


      client     designer             medium     audience

communication problem levels
• Shannon and Weaver discuss three ‘levels’ of
  communication problem: technical, semantic, effectiveness
• technical level
    how accurately can we communicate the message?
    which system to use to encode the message?
    can the receiver use that system?

• semantic level
    which ‘language’ to use?
    how accurately does our ‘language’ convey the meaning we intend?
    how much can be lost whilst still preserving the meaning?

• effectiveness level
    does the message have the effect we want to achieve?
    what can we do if it doesn’t? .
communication problem levels - graphics
• addressing the technical level;
    ‘scope’; which information, how much, and its extent
    medium; eg newspaper adverts, direct mail, tv and radio
    demographics, identifying the audience, cultural norms

• addressing the effectiveness level
      often considered as an ongoing aspect of the technical level:
      previous lessons learned
      demographic information
      market research, focus groups

• relationship between technical level and effectiveness
  level can be described as ‘feedback’
    specification adjusted and fed back to designer
    Shannon and Weaver did not include this in their original work…
communication problem levels - graphics

      client      designer             medium      audience

    company        media
     charity                                       customer
   government      studio                          traveller /
   organisation                                      visitor

noise: redundancy and entropy
• noise - anything ‘added’ between sender and receiver
    obvious source of noise is reproduction; eg newspaper print; technical
    noise at effectiveness level comes from things like audience
     distractions, product placement, dimensions of signage, etc

• redundancy - repeating all or part of the message
    newspaper headlines contain little redundancy; ‘Child Killer Held’
    redundancy can clarify the message; providing pictogram and text

• entropy - measure of uncertainty contained in message
      an ambiguous message has a high entropy
      noise dilutes a message and hence increases entropy
      a ‘long’ message does not necessarily contain a lot of information
      redundancy makes the message longer, but usually reduces
       ambiguity, so can reduce entropy .
the semantic level
• Shannon and Weaver’s model was based in
  mathematics and communication engineering;
• grounded in a field where the semantic level is largely
    choice of language depends on application, eg; a human language, an
     electronics communication protocol
    accuracy of language informs choice - you wouldn’t chose a human
     language for a fire-control system or vice versa!
    ‘robustness’ of the language (and hence how much information can be
     lost without losing the message) are engineering constraints;

• so the process model tends to treat the message as
  something to be encoded, transmitted and received
    does not have much to say about the message itself…
limitations of process models
• models like Shannon and Weaver’s treat
  communication as a linear process;
      a message needs to be passed from A to B
      encode the message in a suitable format
      anticipate problems such as noise and compatibility
      build in robustness with redundancy
      analyse the result with measures such as entropy

• as a result the meaning of the message is determined
  before it leaves the sender
    process models consider minimum and maximum factors required to
     maintain integrity of the meaning such as;
    the minimum redundancy required
    the maximum information that can be carried by a channel
    etc .
process theory and semiotic theory
• as we’ve seen, semiotics considers the role of the
  ‘reader’ when interpreting the ‘text’, eg;
    red can be associated with evil or with good luck depending on culture
    red can mean danger and stop, or can mean romance and passion
     depending on context, within the same culture

• in semiotic approaches, the meaning of the message is
  fixed by the receiver, not by the sender!
    this takes into account noise introduced between sender and receiver
    also takes into account differences in culture
    also takes into account different associations in the same culture

• when combined, process theory and semiotics provide a
  complete framework for analysing effective visual
•   Noble, I. & Bestley, R., 2007. Visual Research: An Introduction to Research Methodologies in
    Graphic Design, AVA Publishing.
•   Crow, D., 2003. Visible Signs: An Introduction to Semiotics, AVA Publishing.
•   Baldwin, J. & Roberts, L., 2006. Visual Communication: From Theory to Practice, AVA Publishing.
•   Chandler, D., Semiotics for Beginners,
• - biography of Shannon with links to his

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