Movement detection by cats: Invariance with direction and target configuration.

Abstract
Absolute thresholds for movement detection were measured in 3 cats and 2 human subjects under similar conditions. A 2-alternative spatial forced-choice procedure was used with the method of constant stimuli. When targets were moving random-dot patterns, cat thresholds ranged from 0.6.degree.-2.3.degree./s, while human thresholds were approximately 0.05.degree./s. Similar thresholds were found for cats tested with square wave gratings ranging ins spatial frequency from 0.18-1 cycle/degree. Neither cats nor humans showed any directional asymmetry for motion detection.