title: Symmetry perception and spatial-frequency channels.
abstract: 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.
mesh_terms: D003867:Depth Perception; D005556:Form Perception; D006801:Humans; D009949:Orientation; D010364:Pattern Recognition, Visual; D010470:Perceptual Masking; D013028:Space Perception