ABSTRACT
Under size constancy the perceived size of an object docs not change as we approach it, despite large changes in the size of that object's retinal image. The experiments in this chapter demonstrate a breakdown of size constancy under stroboscopic illumination. This effect is a tuned function of strobe frequency. In the vicinity of 8 Hz, objects appear to loom dramatically as we approach them and shrink as we back away. The magnitude of the effect also depends on the spatial frequency of the target, and perhaps more important, on whether the pattern stimulates the peripheral retina. If only the central retina is stimulated by the pattern, or if there is no relative motion between the observer and the pattern, the looming effect disappears and size constancy is regained.
