Spatiotemporal Characteristics of Visual Localization. Phase 2
Abstract
We have conducted psychophysical experiments to determine (1) the contribution of local spatial filters to separation discrimination and(2) the properties of mechanisms that enter into subsequent stages of spatial processing i.e., separation discriminators. The separation, eccentricity, spatial extent, exposure duration, and proximity of the targets to other objects were manipulated. The extent of the target was more important for discrimination of relatively small (rather than large) separations at any given eccentricity, supporting the idea that an additional stage beyond the local spatial filters is necessary to explain performance of separation discrimination. The proximity of other spatial features was found to affect thresholds only for briefly exposed targets, implying that subsequent mechanisms can select the frequency content of the information carried by the local spatial filters. Separation discrimination appeared to be performed by two different types of separation discriminators one largely separation-dependent, and the other separation-independent but strongly eccentricity-dependent. Unlike the local spatial filters the separation discriminator processes information serially, with each separation taking at least 100 ms to encode. Keywords: Human vision; Visual psychophysics; Visual spatial localization.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1989
- Accession Number
- ADA212934
Entities
People
- Christina A. Burbeck
- Duane K. Bowman
- Yen L. Yap
Organizations
- SRI International