Without venturing into neurology, let me suggest a few more characteristics of the symbol as such, that might help provide a more concrete idea of how cultural change proceeds:
- Symbols derive their individual relevance and behavioral effectiveness from the fact that they are built out of our conscious experience -- they are experiential containers, in a sense, that group or classify experiences on the basis of the abstraction of features. E.g., the symbol corresponding to the word "tree" is an abstraction from our experiential encounters with a number of different concrete instances.
- Because of this, symbols can be related to one another hierarchically, in levels of abstraction, like containers that contain, and are contained in, containers -- e.g., "tree" relates to "poplar" in one direction and to "plant" (as opposed to "animal") in the other.
- If we think of the "shape" of a given symbol as determined by its abstracted features, then this shape is a malleable one, as those features are constantly being adjusted under the pressure of new experience, including especially communicative experience. That shape also affects how it fits with other, related symbols.
- At any point, new symbols can be made up by agglomerating new abstractions from experience -- we might decide we need a new category of "plants suitable for urban landscaping", for example, and give such a thing a name (sign).
- Also at any point, new symbols can be formed by introducing a distinction that breaks an existing one into new, more usable parts. (In fact, these may well be the twin fundamental operations that underlie all thought: comparing/distinguishing, associating/discriminating, synthesizing/analyzing.)
Consider, for example, a micro-incident: X sees an odd-looking plant (to her), and says to Y: "Look at that odd tree," and Y replies, "Actually, that's a shrub, not a tree." At first, X's tree-symbol has been altered to some extent by the need to include this new experience -- and then it's quickly altered again by Y's reply, which serves at least momentarily to bring the two into greater (but certainly never exact) "semantic alignment". X may try to argue the point, may be puzzled about it, or may simply accept the correction, but in any case, both will have had their symbols associated with the words "tree" and "shrub", as well, perhaps, as their notions of each other, affected, however slightly, by both the perception and the communication. And the affect will not, typically (though it can), be a matter of their conscious wills or agencies -- it will be a matter of the mechanism of cultural adaptation.