Saturday, March 31, 2012

The Ecological Approach to Visual Perception

James J. Gibson offered a new visual perception theory, opposed to the gestalt psychology. In this post, let me explain general concept of it.

Visual Perception of Gestalt Psychology

Before Gibson, perception theories like that of Gestalt psychology suggested that all perceptions, including visual perceptions, are based on one’s experience and the cognitive organs (a reference for the theory would be “metaphors we live by”). In other words, in order to perceive the world, one must already have ideas about it.

According to Prof. Gibson, however, it is circular reference of perception, since if a new perception requires a preceding experience within one’s mind, one needs to already have the new experience, before he or she experiences it.

Ecological Approach to Visual Perception

To overcome the problem of circular reference, professor Gibson came up with the ecological approach to visual perception. The hypothesis assumes that the inner system of human being does not construct the perception based on stimulus, but the environment in itself provides its information for our direct perception (the notion about the direct perception is called information pickup theory). According to the hypothesis, the perception of the environment is based on invariant-extraction from the flux, not based on a sequence of snapshots. The style of perception is ecological, because the perception is not made solely by human beings, but by the interrelationship among the constituents of the environment. Gestalt theory requires gestalt within one’s mind, but the ecological approach to visual perception requires gestalt within the environment.

Related to prof. Gibson’s visual perception theory, there are some important concepts. I would like to mention about them.

One is the interrelationship between subject and object in visual perception. Prof. Gibson claimed that one perceives both environment and oneself at the same time. It is in some sense obvious: when we walk around, we see our legs as well as the changing sight of the outer environment. When we look around the environment, whatever goes out of sight comes into sight, and what ever comes into sight goes out of sight.

“The head turns, and whatever way in back of the head at one time will be in front of the head of another and vice versa. This fact is fundamental for the theory of perception.” (page 112)

Another is affordance theory. Affordances are all action possibilities latent in the environment, objectively reasonable and independent of the individuals’ ability to recognize them, but always in relation to the action and therefore dependent on the individuals’ capabilities. According to the theory, the world is perceived not only in terms of object shapes and spatial relationship but also in terms of object possibility of action (affordance). For instance, when we are looking at a building (environment), we know that the image changes (affordance), when we walk around the building. Gibson argued that we perceive the affordances because of our life needs: environments offer benefit, injury, life, death, and the other critical effects.

The third is our direct perception of layout. When we look at the sight of a road, we perceive it neither as 2 dimensional nor as 3 dimensional. Instead, we perceive it as a layout, prof. Gibson argued. For example, when we look at a sight and estimate the distance from here to the building over there, we can estimate the distance not because we are able to perceive the visual environment in 3D, but because we just directly understand the layout of the things in the environment: for instance, if the road is made of bricks, we will be able to estimate the distance from here to the building by counting approximately how many bricks are there between here and there. This concept of direct visual perception explains why we sometimes wrongly estimate the distance.


It was a tough book to fathom the concept. The explanation of direct perception theory was difficult to follow, but after spending some days, I finally realize what he said. What he offered was a Copernican change in perception theory, which was quite interesting and worth for deep consideration. With that said, I still don’t quite understand which theory is correct: direct or indirect visual perception. Especially, I don’t know why we can say that the experience has no impact on our way of perception. The argument is a bit counter-intuitive.

James J. Gibson, “The Ecological Approach To Visual Perception”, 1986/10/13, Psychology Press

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