title: Binocular contrast summation--II. Quadratic summation.
abstract: Quadratic summation is presented as a rule that describes binocular contrast summation. The rule asserts that for left-eye and right-eye contrasts CL and CR, there is an effective binocular contrast C given by the formula: (formula; see text) Pairs of left-eye and right-eye stimuli that produce equal values of C are equivalent. Quadratic summation is applied to the results of experiments in which stimuli presented to the two eyes differ only in contrast. It provides a good, first-order account of binocular summation in contrast detection, contrast discrimination, dichoptic masking, contrast matching and reaction time studies. A binocular energy-detector model is presented as a basis for quadratic summation.
mesh_terms: D005556:Form Perception / Q000502:physiology*; D006801:Humans; D008027:Light; D008954:Models, Biological; D010364:Pattern Recognition, Visual / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D012684:Sensory Thresholds; D014785:Vision, Ocular / Q000502:physiology*