November 1972
Note on the Concept of “What is Given”
J. J. Gibson
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 References to these essays must cite them explicitly as unpublished manuscripts.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.
Consider the very widely accepted assumption that in order to perceive or know anything one must go beyond what is given. The term given implies given in stimulation, or given to the senses.
I deny this assumption insofar as it means that one must go beyond what is available in stimulation, or to the senses. I agree with it, of course, if what it means is that stimuli or sensations, as ordinarily understood, constitute perception. But I do not agree that stimuli and their sensations are what is given in perception, that is, are the data of perception. When we speak of “going beyond the data,” we mean a process of making guesses, inferences, or constructions on the basis of incomplete or insufficient information, and what I deny is that perceiving and knowing are acts of that sort. In order to make this denial persuasive, it is true, I have to show that what is given to observer by the environment is complete or sufficient information in normal circumstances, that is, when stimulation is ambient and structured and changing, which is to say when it contains information.
Consider what follows theoretically if we take what is given to refer to the stimuli for the receptors or the inputs of the senses, the sensations. These data are wholly inadequate information for perception, incomplete and insufficient. (Note parenthetically that they are often called “sensory information” or are said to be “signals” that are “coded”, but that is a quite different use of the term.) Hence one must go beyond these data. If these are all that the organism has available the process of perception has to be constructive, perhaps even creative. If we accept sensory physiology as the theoretical starting point, with the doctrine of stimuli, inputs, and sensations, we are led to try to discover how input is “transformed, reduced, elaborated, stored, recovered, and used.” The widespread theory that the input is processed comes from the assumption that the only possible information is input.
There is an alternative theory which denies the importance of input and asserts the importance of invariant-detection. (It applies to everyday perception better than to most laboratory experiments.) The data for perception are not sense-data but formless and timeless invariants. And the data are given in a quite different sense of the term than the one we are used to: they are given by the environment, not by the senses; they are obtained, not imposed; and they are given to the active organism, not to its mind or consciousness. In this novel sense of the term one does not have to go beyond what is given in order to know or perceive something.