Contrast sensitivity near borders: Significance of test stimulus form, size and duration

摘要: Abstract The foveal increment threshold is known to be raised at the boundary between dark and light fields, but there are large differences in magnitude of effect reported. In present paper influence test stimulus size, form duration on this has been investigated. When was a small, 2′ arc, spot, presented for 10 msec, its by only 0.1 log units or even less. bar, parallel boundary, elevated about 0.3 units. raise positively related length bar non-monotonic function diameter circular spot width bar. Increasing small increased slightly no significance. results show that use different stimuli might account discrepancy data reported literature. selective lowering sensitivity bars linear result adaptation masking level receptive fields prolonged spatial frequency filters same orientation as boundary.