Gibson and the Learning of Affordances

Let me add a comment on this passage:

"The central question for the theory of affordances is not whether they exist and are real but whether information is available in ambient light for perceiving them. The skeptic may now be convinced that there is information in light for some properties of a surface but not for such a property as being good to eat. The taste of a thing, he will say, is not specified by light; you can see its form and color and texture but not its palatability; you have to taste it for that."
Gibson, 1979, p.140-141

Andrew, Gary, and Gennady have each proposed that Gibson could handle exploding box cases by appeal to learning.  (Now, this won't work, since your learning is not going to change the ability of a typical affordance to structure light.  The problem is that surfaces are on the outside of objects, but what makes for the typical affordance is on the inside of the object, so the light can reach to affordance to be structured by it.)   And, they are right that Gibson does mention learning about affordances. But, notice that, following this passage, Gibson might well just admit that the palatability of a thing is not specified by light and that you have to learn whether an object affords palatability by tasting it, then .....?  Instead, he presses on with the view that higher-order invariants in light are going to save the day.  So, in what follows in this passage, he is more willing to stay the course in saying that affordances are specified by light than have been Andrew, Gary and Gennady.  But, then again, Gibson apparently didn't consider anything exactly like the exploding box protocol.  So, it seems to me that Gibson is somewhat equivocal regarding how he might handle such cases. 

Rush Hour Revisited 2

Second, suppose that you are playing a visual problem-solving game, such as Rush Hour, or completing a jigsaw puzzle.

Here is, perhaps, a simpler way to get to my point.  Suppose that problem solving is a behavior.  Then, one might have extended behavior without extended cognition.  Cognitive processes are one thing; behavior another.  Cognitive processes contribute to cognitive behavior is the idea.  That's what I take to be the standard cognitivist line.  (Somewhere Chomsky says something like "linguistic behavior is the product of linguistic competence, along with poorly understood factors such as attention, set, etc."  I'm thinking this appeared in Chomsky's Language and Mind, or earlier.)  What muddies the water, perhaps, is the idea that problem solving is properly described as cognitive behavior.  But, why is it cognitive behavior?  Because it includes a cognitive process in the brain of course.

So, I see this appeal to problem solving inconclusive.

Moreover, I think that essentially the same story can be told about Gary Williams example of decision making in sortilege.

So, Gibson's not *that* dismissive

Gibson writes,

I am also asking the reader to suppose that the concept of space has nothing to do with perception. Geometrical space is a pure abstraction. . . . Space is a myth, a ghost, a fiction for geometers. (Gibson, 1979, p. 3).

Ok.  Now that seems pretty dismissive of geometry to me, but I think that Andrew and Gary are probably right that this is a bit hyperbolic.  Gibson apparently does not want to go so far as to not use geometry in his scientific thinking.  After all, it looks as though he implicitly needs at least some geometry, and maybe even some Euclidean geometry (but not necessarily Cartesian co-ordinates), to determine how the ambient optic array changes when a person goes from sitting to standing.

From Gibson, 1979, p. Figure 5.4.