Prolonged viewing of a high-contrast pattern (the adapter) makes similar patterns harder to detect. This threshold-elevation effect was measured as a function of the contrast of the adapter, with use of sinusoidal grating patterns. Increases in the spatial frequency, temporal frequency, or eccentricity of the stimuli had two major consequences. First, the minimum contrast required for detection...

We studied differences in the development of sensitivity to first-versus second-order global motion by comparing the motion coherence thresholds of 5-year-olds and adults tested at three speeds (1.5, 6, and 9 degrees s(-1)). We used Random Gabor Kinematograms (RGKs) formed with luminance-modulated (first-order) or contrast-modulated (second-order) concentric Gabor patterns with a sinusoidal spa...

The brain may combine information from different sense modalities to enhance the speed and accuracy of detection of objects and events, and the choice of appropriate responses. There is mounting evidence that perceptual experiences that appear to be modality-specific are also influenced by activity from other sensory modalities, even in the absence of awareness of this interaction. In a series ...

Four experiments examined how differences in the properties of the target and surround affect the time required for perceptual filling-in. They examined differences in luminance, orientation, spatial frequency, and color. A larger target/surround difference delayed filling-in ('feature difference effect'). Interestingly, exchanging the target and surround properties significantly varied the tim...

The purpose of the experiments described here was to investigate global image processing using methods that require global processing while eliminating or compensating for low level abnormalities: visibility, shape perception and positional uncertainty. In order to accomplish this we used a closed figure made up of Gabor patches either in noise or on a blank field. The stimuli were circular or ...

We examine the mechanism that subserves visual contour detection and particularly its tuning for the spatial frequency of contour components. We measured the detection of contours composed of Gabor micropatterns within a field of randomly oriented distractor elements. Distractors were randomly assigned one of two spatial frequencies, and elements lying along the contour alternated between these...