8.2 Background

Many important issues in ecological psychology were first identified by J. J. Gibson, a perceptual psychologist whose powerful, incomplete, and often misunderstood ideas have played a seminal role in technologies for simulating navigable environments. Although we do not entirely agree with Gibson's theories, which were still evolving when he died in 1979, his work serves as a useful framework for examining the implications of ecological psychology for media design and research.

We provide here, as an advance organizer, a verbatim list of phenomena that Gibson identified in personal notes as critical to the future of ecological psychology (J. J. Gibson, cited in Reed, 1971/1982, p. 394):

1. Perceiving environmental layout (inseparable from the problem of the ego and its locomotion)
2. Perceiving the objects of the environment (including their texture, color, shape--and including their affordances)
3. Perceiving events (and their affordances)
4. Perceiving other animals and persons ("together with what they persistently afford and what they momentarily do")
5. Perceiving the expressive responses of other persons
6. Perceiving by communication or speech
7. Knowledge mediated by artificial displays, images,pictures, and writing
8. Thought as mediated by symbols
9. Attending to sensations
10. Attending to structure of experience (aesthetics)
11. Cultivating cognitive maps by traveling and sight seeing

According to Gibson (1971/1982), everyday living depends on direct perception, perception that is independent of internal propositional or associational representations--perception that guides action intuitively and automatically. Direct perception, for example, guides drivers as they respond to subtle changes in their relationship to roadway centerlines. Direct perception adjusts the movements required to bring cup to lip and guides the manipulation Of tools such as pencils, toothbrushes, and scalpels. Direct perception is tightly linked in real time with ongoing action.

Perhaps the most widely adopted of Gibson's (1979) contributions to the descriptive language of ecological psychology are his concepts of affordances (roughly, opportunities for action) and effectivities (roughly, capabilities for action). Natural selection gradually tunes a species' effectivities to the affordances associated with its niche or "occupation." Thus are teeth and jaws the effectivities that permit killer whales to exploit the "grab-ability" of seals; and so are wings the effectivities that allow birds to exploit the air.

In contrast to direct perception, indirect perception operates on intermediaries such as diagrams, symbols, words, and propositions that inform an organism or agent about a world or environment via indexical bonds (Nichols, 1991) with that environment. Following verbal directions to locate a hidden object is a good example of indirect perception. Indirect perception permits, even promotes, reflection and deliberation.

Gibson acknowledged the importance to human thought of such intermediaries as symbols and language-based propositions. He was skeptical, however, about claims that general cognitive processes can be modeled in terms of such intermediaries, and he argued that models that relied excessively on symbols and propositions would inevitably neglect critical relationships between perceiving and acting.

Although Gibson (1977/1982) did not develop a complete theory of mediated perceiving (see 7.3.4)--that is, perception through intermediaries such as pictures and text--he posited that such intermediaries are effective because they are "tools for perceiving by analogy with tools for performing" (p. 290). Careful appraisal of this idea reminds us that in the Gibsonian world view, everyday perceiving cannot be separated from acting. Therefore, there is no contradiction in the assertion that "tools for perceiving" might serve as analogs for action. Static media such as text, diagrams, pictures, and photos have traditionally achieved many of their most important informative effects by substituting acts of perception for acts of exploration.

Every media technology from book to video to computer simulation, however, imposes profound constraints on representation or description of real or imaginary worlds (see 12.3.1) and requires trade-offs as to which aspects of a world will be represented. Even museums, as repositories of "unmediated,"' authentic artifacts and specimens, must live within the technical limitations of display technologies that favor some modalities of perception over others--looking in lieu of touching, for instance.