How direct is visual perception?: some reflections on Gibson's "Ecological Approach'.

1. Introduction There is always a scientific Establishment, and what it believes is always more or less untrue. Even in the respectable sciences empirical knowledge is forever undergoing reformulation, and any generation's pet theories are likely to look naive when viewed from the perspective of thirty or forty years on. In psychology ,however, reformulation tends to be radical. When the dominant paradigm goes, the whole picture of the mind may shift; and, often enough, the scientific consensus about what constitutes a psychological explanation changes too. At such times, to use a phrase of Gibson's, the "old puzzles disappear,"' (p. 304) and one may be hard put to understand what on earth one's predecessors thought that they were up to. This has happened so often in the history of psychology that it would surely be unwise .to assume that it is not going to happen again; in particular, it would be unwise to assume that it is not going to happen to us. Gibson thinks that it has already, and it seems that a substantial minority of the cognitive science community is inclined to agree with him. The purpose of this essay is to examine whether there is anything to that claim. In particular, we will examine the thesis that the postulation of mental processing is unnecessary to account for our perceptual relationship with the world; that if we describe the environment in the appropriate terms we see that visual perception is direct and requires only a selection from information present in the ambient light. The current Establishment theory (sometimes referred to as the "informa-tion processing7' view) is that perception depends, in several respects presently to be discussed, upon inferences. Since inference is a process in which premises are displayed and consequences derived, and since that takes time, it is part and parcel of the information processing view that there is an