On Information Available in Pictures

The author reviews two current conflicting theories of what a picture is: (1) that it consists of a sheaf of light rays coming to a station point orperceiver, each corresponding to a spot of color on the picture surface and hence that the picture can standfor a real object or scene insofar as the rays from the picture are the same as the rays from the real object; (2) that it consists of a set of symbols, more or less like words, and the perceiver must learn to 'read' it. According to the first theory, a child can perceive an object in a picture as soon as it can perceive a real object; according to the second one, the child must learn to 'read' the picture much as it learns to read written speech. He points out the fallacies of both theories, shows that they cannot be combined and suggests a new theory based on the radical assumption that light can convey information about the world and, hence, that the phenomenal world does not have to be constructed by the mind (or the brain) out of meaningless data. This theory makes it possible to distinguish between the pictorially mediated perception of the features of a world and the direct perception of the features of the surroundings and yet to understand that there is common information for the features they have in common. His theory accounts for the difference between verbal and visual thinking. Visual thinking is freer and less stereotyped than verbal thinking; there is no vocabulary of picturing as there is of saying. As every artist knows, there are thoughts that can be visualized without being verbalized. Underlying all the discussions of representation there are currently two conflicting theories of what a picture is. The first theory assumes that it consists of a sheaf of light rays coming to a station point or perceiver, each corresponding to a spot of color on the picture surface. The second theory assumes that it consists of a set of symbols, more or less like words, and that a painting is comparable to a written text. On the first theory, a picture can represent a real object or scene insofar as the light rays from the picture are the same as the light rays from the original. On the second theory, a picture can stand for a real object or scene insofar as the language of pictures is understood. The second theory says that one has to learn to 'read' a picture, much as the child has to read written speech, but the first theory denies this and asserts that as soon as a child can perceive an object directly he can perceive it in a picture. One might suppose that these theories as stated are merely extremes, and that they can somehow be combined. But attempts to reconcile them have not been successful, or at least I find them unsuccessful and I have come to believe instead that both theories are wrong. We need a new theory of what a picture is. I will try to suggest later what * Psychology Research Laboratories, Cornell Industrial Research Park, Ithaca, N.Y. 14850, U.S.A. (Received 2 September 1970.) it might be but first let us get clear about the two opposing positions, what the force of the argument is in each case and why in the last analysis they fail. THE POINT-PROJECTION THEORY OF PICTORIAL INFORMATION By the eighteenth century the technique of perspective representation, discovered by painters in the Renaissance, had matured along with the developing science of optics (cf. Fig. 1). An English mathematician could assert in 1715 that in order to produce a perfect painting of objects, 'the Light ought to come from the Picture to the spectator's Eye in the very same manner as it would do from the Objects themselves' 1. It would be as if the light came through a window, to be sure, corresponding to the frame of the picture but if each light ray from a spot of pigment on the canvas were the same in wavelength and intensity as each light ray from a spot on the front face of the object coming to the eye through the window, then the two bundles of light rays would correspond and the representation of the object would be complete. At the time of this assertion, Isaac Newton's treatise on Optics had been published and it was widely read. This theory of the perfect picture seemed to fit