David Peat

The End of Representation 93Scientific studies tell us that the ability to see the world involvesthe integration of a variety of different strategies operating betweenthe eye and brain. The most basic of these are “hardwired” within variousareas of the brain. By the term “hardwired” I mean that all humanbeings, and many animals, have the same genetic instructions that allowfor the development of similar sets of neural pathways responsiblefor vision. In other words, the first steps in seeing turn out to be thesame for all humans. Signals from the optic nerve enter the brain,where they are routed to three separate centers: the midbrain, the cerebellum,and the visual cortex. The latter is itself divided into a varietyof centers; in each of which vision is doing something quite different.Midbrain vision, for example, is also present in much simpler organismssuch as the frog. At this level it is probably true to say that wedon’t actually “see” anything, in the sense of registering a visual scenein our conscious awareness. The more primitive functions of the midbrainare instinctual. When a fly enters a frog’s visual field, the frog’stongue darts out as a reflex action. In human terms the frog could notreally be said to have “seen” the fly just before shooting out its tongue.Vision, in the sense of actually seeing things, begins with processesin the various areas of the visual cortex. One of these processes involvesseeking out edges. Discerning the edge of an object is importantin trying to determine its outline. Other strategies are used to pick outmoving bars, fields of color, areas of movement, and so on. (Whenresearchers design robots to recognize objects they exploit similar strategiesin their computer programs.)These first stages of vision therefore involve the simultaneous, butseparate, processing of information received from the eye. At this pointthe brain does not yet “see,” for example, a red and yellow box fallingfrom a window, but rather a series of edges, a field of movement, someareas of color, and so on. Next the various outputs of visual materialare integrated to form a visual whole. It is only at this point that we“see” a falling red and yellow box, or a blue car driving away from us,or a man waving.The description above approached vision from one side only, forseeing is also very much about the act of doubting. As the brain attemptsto integrate the visual clues it has collected, it rapidly makes a