The waggon-wheel effect.

The waggon-wheel effect was studied by use of three wheels with different numbers of spokes (4, 8, 16) and a wide range of strobe temporal frequencies. The results obtained are discussed in terms of a model in which: (i) nearest-neighbour relationships predict the direction and speed of movement, (ii) persistence and masking occur over ranges consistent with values reported in the literature, (iii) apparent motion is generated between currently illuminated spokes and persisting images of spokes, (iv) duration of spoke illumination (sweep) is a determining factor and, (v) a top-down process finds the best fit (a sort of 'simple structure') for the complex spatiotemporal display.