ABSTRACT
It comes as a surprise to discover that the foveal area in which one has high resolution and high acuity vision is minute; it encompasses a mere 2° of visual angle-roughly, the area of the thumbnail at arm's length. The introspective guess concerning acuity in depth likewise errs on the side of extravagance; the region of crisp, fused perception is, at arm's length, only a few centimeters deep; closer in, the area of fused perception is even narrower. The eyes make a small movement-a saccade-about every 200-300 milliseconds, sampling the scene by shifting continuously the location of the fovea. Presumably interpolation across intervals of time to yield an integrated spatiotemporal representation is a major component of what brains do. Interpolation in perception probably enables generation of an internal representation of the world that is useful in the animal's struggle for survival.
