Orientation selectivities of tilt illusion for chromatic and luminance stimuli
Simultaneous orientation contrast, or tilt illusion (TI), is known as misperception of orientation of a stimulus when it is juxtaposed with another stimulus of a different orientation. Using isoluminant chromatic and isochromatic luminance gratings, magnitude of TI was measured as a function of orientation difference between the test and the inducing gratings. The results showed that TI occurred for the chromatic as well as the luminance gratings, and that the TI vs. orientation difference functions for the chromatic gratings were broader than that for the luminance gratings. These results suggest that chromatic information on its own contributes to the processing of stimulus orientation, and the orientation selective mechanisms sensitive to chromatic contrast are more broadly-tuned than those sensitive to luminance contrast.
富山県立大学紀要 4, 32-43, 1994-03