Derrington and Henning (1981)¹⁾ reported that orientation discrimination performance has a low-pass spatial frequency characteristic, and argued that a mechanism for spatial pattern processing functions at fairly low spatial frequencies. To test their claim, we measured spatial frequency characteristics for orientation discrimination using vertical and horizontal Gabor patches with either counter-phasing or on-off temporal modulation. The results showed that the orientation discrimination sensitivity for counter-phasing stimuli was about twice that for on-off patterns at low spatial frequencies. These results indicate that orientation discriminations in these conditions are based on the directional components contained in the temporally modulated patterns instead of pattern information that is related to total depth of modulation.

It has been said that the static or dynamic tilt of large-visual-stimulus produces the perception of observer’s tilt, and that this misperception would cause the postural sway. But it has been shown that the reaction time of postural control was shorter than that of vection. The present study compared the effects of large-visual-stimulus on postural control and perceptual responses. A photo slide was projected onto a large hemispheric screen and tilted. Participants responded the perceived self and stimulus tilts in degree, and their body sways were measured. The results showed that the large-visual-stimulus tilt affected postural control and the effect changed with time, however, on the perceived self and stimulus tilts, it didn’t show clear effects or differences between timings of responses. It was suggested that the misperception wouldn’t always cause the biases of motor control, and that visual information pathways might be different according to what people do.