|Anisotropy in the chromatic channel: A horizontal-vertical effect.
Compared the patterns of luminance and chromatic contrast thresholds for drifting gratings at 4 orientations and 3 spatial frequencies. The authors and 2 other Ss served as observers. They had normal or corrected-to-normal acuity and no measurable astigmatism or color vision defects. The stimuli were sine-wave gratings modulated in color (red-green) or luminance (yellow-black). Results show a significant difference between the horizontal and vertical thresholds (H-V Effect) that was present only for chromatic thresholds. The classic oblique effect was found for high spatial frequency luminance and chromatic stimuli. (PsycINFO Database Record (c) 2007 APA, all rights reserved)