Intuitively it may seem likely that orientation-modulated (OM) and frequency-modulated (FM) textures are processed utilizing the first-order channels that are most responsive to the first-order (luminance) information contained in the textures. This assumption would imply that the detection or segmentation of OM or FM textures is accomplished by second-order mechanisms that receive their first-...

Speed matches were obtained, using a spatial two-alternative forced-choice task, between a second-order motion stimulus and a first-order motion stimulus. The second-order motion stimulus was composed of contrast-modulated noise [produced by multiplying two-dimensional (2-d), static noise by a drifting, one-dimensional (1-d) sinusoid]. The first-order motion stimulus was composed of luminance-m...