Spatio-temporally averaged positions of moving objects

This study investigated the case where a spatial offset was periodically and momentarily introduced between two vernier components during their excursion, to determine how such an offset affects the relative localization of the components. If the object in motion is perceived at a position averaged over a limited spatio-temporal range, spatial offsets in a moving vernier should be perceived accordingly. This prediction was confirmed by the outcome of the first experiment. A second experiment was performed to inquire into the relationship between vernier threshold and the averaging of spatial offset, and also the spatio-temporal limit of the integrative process. The upper temporal limit of the averaging was estimated to be about 50 ms, and the spatial extent of positional modulation was shown to have a significant effect on the detection of vernier offset. It was found that the larger the extent over which the vernier positions were distributed, the smaller the offset detected between them. It is suggested that spatial offset can be detected directly, perhaps by some mechanism sensitive to the phase relationship of the components of visual patterns.