An inverse oblique effect in human vision.
In the classic oblique effect contrast detection thresholds, orientation discrimination thresholds, and other psychophysical measures are found to be smallest for vertical or horizontal stimuli and significantly higher for stimuli near the +/-45 degrees obliques. Here we report a novel inverse oblique effect in which thresholds for detecting translational structure in random dot patterns [Glass, L. (1969). Moiré effect from random dots. Nature, 223, 578-580] are lowest for obliquely oriented structure and higher for either horizontal or vertical structure. Area summation experiments provide evidence that this results from larger pooling areas for oblique orientations in these patterns. The results can be explained quantitatively by a model for complex cells in which the final filtering stage in a filter-rectify-filter sequence is of significantly larger area for oblique orientations.
Wilson
H R
HR
Centre for Vision Research, York University, 103 Farquharson, 4700 Keele Street, Toronto, Ont., Canada M3J 1P3. hrwilson@yorku.ca
Loffler
G
G
Wilkinson
F
F
Thistlethwaite
W A
WA
D015350:Contrast Sensitivity / Q000502:physiology*; D004056:Differential Threshold / Q000502:physiology; D004192:Discrimination, Psychological / Q000502:physiology; D005583:Fourier Analysis; D006801:Humans; D008959:Models, Neurological; D009010:Monte Carlo Method; D016011:Normal Distribution; D009949:Orientation / Q000502:physiology*; D017603:Signal Detection, Psychological / Q000502:physiology