Thursday, July 27, 2006

Gibson, "Theory of Affordances"

Gibson, James J. "The Theory of Affordances." Perceiving, Acting, and Knowing. R.E. Shaw and J. Bransford, eds. Hillsdale, N.J.: Elrbaum, 1977.

Gibson's seminal essay introduces the term, affordances, and articulates the nuances in its application to ecological psychology. An affordance, according to Gibson, is "a specific combination of the properties of its substance and its surfaces taken with reference to an animal" (67). Affordances are species-specific; they are functionally generic, in this sense, applying differently according to the physiological tendencies of an animal.

Affordances are those perceived aspects of the environment that suggest suitability to habituated action (action likely to be carried out in kind by others of the species). Objects, substances, and events all afford activities (^events afford exigence). Niche, for Gibson, is a set of affordances (how one lives rather than where, rather than habitat). And while niches are not, strictly speaking, places, they involve occupation and suitability (even sustainability?). They also take root in a middle space between the subjective and objective, according to Gibson (69). An affordance is not wholly dependent on the observer's perspective nor on the absolute physical properties of an object. Niche, however, guides us toward an understanding of affordances as real--constitutive of the phenomenal environment (70).

Gibson further develops the concept of affordances using a series of question-guided subsections:

What do substances afford? (71): ripeness and pleasure
What do surfaces and their layouts afford? (72): obstacles and locomotion
The Affording of Concealment (73): from ecological optics, concealment involves positioning relative to layout
What do detached objects afford? (74): manipulation and tool-use
What do other animals and other people afford? (75): interaction, animation and othering
Summary: Positive and Negative Affordances (76): "There has been endless debate among philosophers and psychologists as to whether values were physical or phenomenal, in the world of matter or only in the world of mind. For affordances as distinguished from values the debate does not apply. They are neither in the one world or the other inasmuch as they theory of two worlds is rejected. There is only one environment, although it contains many observers with limitless opportunities for them to live in it" (77).

In the section titled, "The Origin of the Theory of Affordances," Gibson situates affordances in work by Gestalt psychologists. He invokes valence, a concept he attributes to Lewin which applies to the behavioral object rather than the geographical object. The phenomenological object is entangled with the intensities of the user. But Gibson wants to qualify affordances as something more persistent than vectors and valences (78).

In the final section of the essay, Gibson distinguishes between perceiving and misperceiving affordances. The need for perception means that affordances can also be misperceived. : "No wonder, then, that quicksand is sometimes mistaken for sand, that a pitfall can be mistaken for solid ground, that poison ivy is sometimes mistaken for ivy, and that acid can be taken for water" (81).

"Now just as surfaces are stand-on-able and sit-on-able so also are they bump-into-able or get-underneath-able, or climb-on-able, or fall-off-able" (68).

^Is Gibson's a modernist project dependent on restrictive (or regular) patterns of human behavior?  What, if not an affordance, is the experimental edge of the thing-in-use? Are affordances incompatible with singularity? Given the ties to perception (and ecological optics), this is an interesting pairing with VV's "Seeing in Third Sophistic Ways."

Key phrases: Koffka's "demand character" (77), Kurt Lewin's "invitation-character" (78), valence (78), vectors (78),

Related sources:

Koffka, K. Principles of Gestalt Psychology. New York: Harcourt, Brace, & World, Inc., 1935.

Posted by Derek Mueller at July 27, 2006 3:20 PM to Tools-in-use