Antagonistic effects of adjacency and apparent speed in induced movement.

Two experiments concerning induced movement are reported. The hypothesis was that when outline inducing frames were used, object-relative displacement was modified by two variables, adjacency and apparent speed. Adjacency is directly related to the magnitude of induced movement. Small outline frames are high in adjacency, and so small frames should be powerful generators of induced movement. On the other hand, several investigators have found the speed of the inducing frame to be inversely related to the magnitude of induced movement. It is hypothesized here that this effect of speed was determined by apparent speed (not real speed), and if so, since small objects appeared to move faster than large ones, a small outline frame should be a relatively weak generator of induced movement. In the first experiment, this hypothesis was tested using single inducing frames. In the second experiment, this hypothesis was tested using two inducing frames presented simultaneously. The implications of these experiments were discussed with regard to other theories of induced movement.