Distance Perception in an Optical Tunnel: An Ecological Perspective

An optical tunnel, a device that allows manipulation of surface layout in which to-be-perceived targets can be embedded, was used to examine distance perception against the backdrop of predictions from two influential computational approaches. Contrary to expectations of the ground dominance hypothesis, Experiment 1 showed that objects on the ground surface were not perceived more accurately than objects attached to the ceiling. Contrary to expectations from the sequential surface integration process hypothesis (SSIP), Experiment 2 showed that the reliability of distance perception did not differ whether the surface density was continuous or discontinuous and that, for continuous density, reliability did not differ whether it was dense or sparse. Also contrary to SSIP, Experiment 3 showed that manipulation of the surface layout beyond the range of sequential integration mattered to the accuracy of distance perception. Results were discussed within an ecological reframing of the problem of distance perception. To the extent that perception is dependent on detecting an optical invariant, global surface layout should matter and distance perception should not be procedurally different for differences in discontinuity or density. Recasting the notion of distance perception in terms of affordances, behavioral possibilities of objects and surfaces, will provide constraints on identifying the relevant optical invariants