Although the Shannon and Weaver theory has deeply influenced all research areas related with communication and we have presented our metamodel as a step beyond that observes the importance of meaning, it is important to note that some models of human communication do care about meaning and make a central issue of it. It is well beyond our intention to give a thorough overview of such models, mostly related to psychological or sociological arenas but it is interesting to include a brief outline in which we will find some relation with the metamodel we have just presented.
Charles Osgood is the creator of the Meditacional Theory of Meaning [Oswood, 1976], related to his well known semantic differential technique [Snyder and Oswood, 1967]. According to the results of his studies the meaning of any piece of information can be described in terms of only three dimensions: its evaluation (whether it is good or bad), potency (how strong it is) and activity (how fast it moves).
Pierce and Cronen developed a model of communication that strongly relies on meaning. This model is known as the Coordinated Management of Meaning (CMM) [Philipsen, 1995] and its main feature is that instead of focusing on the message, the stress is put on the receiver. People try to understand the world assigning meaning to an event, the problem is that individual interpretations may not coincide. The CMM represents meaning in a six level map that goes from the actual content to the highest level of cultural patterns.
In a similar way the General Semantics Theory[Kodish, 1993] states that you cannot equate a word with the concept that it's supposed to represent. Hayakawa proposes an 'Abstraction Ladder', the actual content can be decomposed into different representations according on the level of abstraction intended. The problem is that as we go higher on the ladder, there is a point where 'speakers' lose the picture of the actual content. He gives the example of an Abstraction Ladder for a picture of a cow. This ladder includes the following levels: (1) Cow as known to science; (2) the actual cow we perceive; (3) "Bessie" (the cow's name); (4) Cow; (5) Livestock; (6) Farm assets; (7) Asset; (8) Wealth. This abstraction ladder is directly related to the multilevel analysis and content description scheme we presented in section 5.2.1.
I.A. Richard developed a theory on the ``Meaning of Meaning'' in which he suggested that context is key to meaning [Ogden and Richards, 1946]. Meaning is personal and in his view of the communication act he extended Shannon and Weaver's traditional model to show the necessity of common experience for the effective transmission of meaning. This idea is also related to the different strategies presented for our Semantic Receiver, outlined in section 5.2.2.
Symbolic Interactionists, represented by George Herbert Mead, state that the extent of knowing is the extent of naming: intelligence is the ability to symbolically label everything we encounter [Mead, 1910].
Harold Lasswell [Cherry, 1957] suggested a simple but useful model, which captures the essence of message transmission and is made of the following elements: Who, says What, to Whom, in Which medium, with what Effect.
Finally it is also important to acknowledge that also some other researchers in the audio processing field noted that S&W's disregard for meaning imposed too many restrictions on our domain. In particular, the developers of the Structured Audio metamodel, which will be presented in next section, also presented their model as a step beyond S&W's.