Ecological Psychology and Homeokinetics

October 1976

Five Kinds of Knowing (Supplement to Note of March 1976)

J. J. Gibson, Cornell University

 

The World Wide Web distribution of James Gibson’s “Purple Perils” is for scholarly use with the understanding that Gibson did not intend them for publication. References to these essays must cite them explicitly as unpublished manuscripts. Copies may be circulated if this statement is included on each copy.

Instead of trying to define or redefine such vague terms as seeing, perceiving, conceiving, imagining, and visualizing, we might try to formulate various levels of knowing. The following tentative kinds of cognitive awareness correspond to various levels of comprehension of the environment. They involve increasing degrees of exploration over increasingly longer intervals. The pickup of information over time is assumed (not the processing of discrete sensory inputs). The levels of awareness being considered are those of tacit knowledge; the effect of making knowledge explicit is another question. We are primarily interested in knowledge at first hand.

Consider the various possible levels of visual knowing. The human visual system seems to show the most elaborate levels of awareness of the environment.

1. Awareness of the facing surfaces in the temporary field of view. This is the “seeing” of the unhidden surfaces that are samples at a fixed point of observation with a fixed head. It is analogous to the “picture” obtained by a single eye, each surface of the environment corresponding to a visual solid angle in the optic array.

Exploratory eye-movements are assumed, but not head-turning. There is, of course, a special awareness of the surface at which one is looking for each eye fixation, i.e., an awareness of what is foveated, but this lasts for only a fraction of a second in ordinary perception. One “sees” more than what is foveated even during a single fixation.

2. Awareness of all the facing surfaces of the surrounding environment. This is the level of knowing that occurs with looking around. It includes the world behind one’s head as well as that in front of one’s head. But it is still the environment from a single temporary point of observation, now and here. It is awareness without locomotion.

If the pickup of binocular disparity is assumed, i.e., the difference between the array at one eye and the array at the other, then it is as if one could see from two points of observation simultaneously. But this is not yet knowledge with locomotion. Note that information for the perception of the layout of surfaces is plentiful at these first two levels of knowing. The traditional belief that perceiving begins with a flat patchwork of color sensations has been rejected.

3. Awareness of the facing and the non-facing surface in the relatively near environment. This is knowledge at the level of surfaces connected at occluding edges, including the far sides of objects and the backgrounds of objects. It occurs with getting around in addition to looking around, in the course of general exploratory activity. The places of the habitat merge into one another as a consequences of the transitions between vistas during locomotion.

At this level the observer is aware of and oriented to objects and places that are temporarily “out of sight” as well as to surfaces that are now “in sight.” This is the familiar environment of frequent locomotion to and from places.

4. Awareness of surfaces in the far environment. This is the kind of knowledge achieved by travelers and explorers, i.e., of far places outside the habitat. It depends on locomotion over longer periods of time. The transitions between vistas are not so familiar, and “finding the way” is not so easy. But we know more and more from year to year.

At this level second-hand knowledge begins to be important for supplementing first-hand acquaintance, i.e., knowledge mediated by verbal descriptions, pictures, and maps.

5. Awareness of the general features of the whole environment. We come to know the environment not only by locomotor exploration but also by such activities as manipulating, scrutinizing, and analyzing. We thus learn to perceive the affordances of things wherever they are encountered, and we continue to learn more as we go on living. This is “general” knowledge, sometimes called “abstract,” since it deals with properties, qualities, variables or features of persisting things.

Awareness of the world at what might be called the “conceptual” level cuts across awareness of the surrounding environment at the “terrestrial” levels listed above, or so it might seem. But the classical distinction between conceptual and perceptual is outworn. How should the difference be described?