Opponent model for line interval discrimination: interval and vernier performance compared.
Vernier and spatial interval thresholds were determined as a function of contrast, using thin bars with a Gaussian luminance profile. The previously reported contrast dependence of vernier acuity was confirmed, but contrast had a much smaller effect upon interval acuity. A subsidiary experiment showed that the relative contrast of the two bars in an interval discrimination could be randomly perturbed over trials without substantially reducing acuity. A model of interval discrimination is developed, including an opponent stage between hypothetical spatial coincidence detectors.
D004192:Discrimination, Psychological / Q000502:physiology; D005556:Form Perception / Q000502:physiology*; D006801:Humans; D008959:Models, Neurological; D010364:Pattern Recognition, Visual / Q000502:physiology*; D012684:Sensory Thresholds / Q000502:physiology; D014792:Visual Acuity