Spatiotemporal Characteristics of Human Visual Localization
Final rept. 1 Oct 1990-31 Dec 1991,
NORTH CAROLINA UNIV AT CHAPEL HILL
Pagination or Media Count:
Psychophysical studies of the processes underlying relative localization in human vision were conducted. Specifically, the focus of this granting period was characterizing the spatial characteristics of the units that encode spatial location. Evidence was found for a higher-order scaled representation of position in which the size of position integration areas scales with the distance being encoded. This scaling of the position integration areas was found to account well for the increase in separation discrimination thresholds with increasing separation. The position integration areas were shown not to integrate luminance, but were shown to depend on an initial spatial organization of the scene. The time course of the position integration was also investigated. Additional studies investigated the relationship between position integration and the Muller-Lyer illusion, and the effect of the spatial frequency of a masking stimulus presented at termination of the separation discrimination stimulus on separation discrimination thresholds.