"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."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.
Gibson, 1979, p.140-141
Thursday, February 10, 2011
Gibson and the Learning of Affordances
Let me add a comment on this passage: