It is known that the sum of a random-dot array with vertical bilateral symmetry and one with horizontal bilateral symmetry appears as a random array. Here we show that if the vertically and horizontally symmetrical arrays are spatially filtered, so that their respective spectra are 2 octaves apart, then their superposition does not appear random, but both symmetries can be simultaneously perceived. The low-band array has a stronger perceptual weight than the high-band array. These demonstrations give further evidence that frequency channels are before symmetry perception.
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References
1.
BlakemoreCCampbellF W, 1969“On the existence of neurones in the visual system selectively sensitive to the orientation and size of retinal images”Journal of Physiology (London)203237–260
2.
GinsburgA P, 1975“Is the illusory triangle physical or imaginary?”Nature (London)257219–220.
3.
HarmonL DJuleszB, 1973“Masking in visual recognition: Effects of two-dimensional filtered noise”Science1801194–1197.
4.
JuleszB, 1966“Binocular disappearance of monocular symmetry”Science153657–658.
5.
JuleszB, 1971Foundations of Cyclopean Perception (Chicago: University of Chicago Press).
6.
JuleszB, 1975“Experiments in the visual perception of texture”Scientific American232(4) 34–43.
7.
JuleszBMillerJ E, 1975“Independent spatial-frequency-tuned channels in binocular fusion and rivalry”Perception4125–143.
8.
MayhewJ E WFrisbyJ P, 1978“Contrast summation effects and stereopsis”Perception7537–550.
9.
PantleASekulerR, 1968“Size-detecting mechanisms in human vision”Science1621146–1148.
