daniel_c_dennett's picture
Philosopher; Austin B. Fletcher Professor of Philosophy, Co-Director, Center for Cognitive Studies, Tufts University; Author, From Bacteria to Bach and Back

Psychologist James J. Gibson introduced the term affordance way back in the seventies. The basic idea is that the perceptual systems of any organism are designed to “pick up” the information that is relevant to its survival and ignore the rest. The relevant information is about opportunities  “afforded” by the furnishings of the world: holes afford hiding in, cups afford drinking out of, trees afford climbing (if you’re a child or a monkey or a bear, but not a lion or a rabbit), and so forth. Affordances make a nicely abstract category of behavioral options that can be guided by something other than blind luck—in other words, by information extracted from the world. Affordances are “what the environment offers the animal for good or ill,” according to Gibson, and “the information is in the light.” (Gibson, like most psychologists and philosophers of perception, concentrated on vision.)  While many researchers and theoreticians in the fledgling interdisciplinary field of cognitive science found Gibson’s basic idea of affordances compelling, Gibson and his more radical followers managed to create a cult-like aura around his ideas, repelling many otherwise interested thinkers.

The huge gap in Gibson’s perspective was his refusal even to entertain the question of how this “direct pickup” of information was accomplished by the brain. As a Gibsonian slogan put it, “it’s not what’s in your head; it’s what your head is in.” But as a revisionary description of the purpose of vision and the other senses, and a redirection of theorists’ attention from retinal images to three-dimensional optical arrays (the information is in the light) through which the organism moves, Gibson’s idea of affordances has much to recommend it—and we’ll do a better job of figuring out how the neural machinery does its jobs when we better understand the jobs assigned to it.

Mainly, Gibson helps us move away from the half-way-only theories of consciousness that see the senses as having completed their mission once they have created “a movie playing inside your head,” as David Chalmers has put it. There sometimes seems to be such a movie, but there is no such movie, and if there were, the task of explaining the mind would have to include explaining how this inner movie was perceived by the inner sense organs that then went about the important work of the mind: helping the organism discern and detect the available opportunities—the affordances—and acting appropriately on them. To identify an affordance is to have achieved access to a panoply of expectations that can be exploited, reflected upon (by us and maybe some other animals), used as generators of further reflections, etc. Consciousness is still a magnificent set of puzzles, but appears as less of a flatfooted mystery when we think about the fruits of cognition with Gibson’s help. The term is growing in frequency across the spectrum of cognitive science, but many users of the term seem to have a diminished appreciation of its potential.