1. Visual Information Processing October 30, 2014

2. Feature Detectors Certain cells in the visual cortex (occipital lobe) respond to specific features of a scene They then pass information to supercell clusters on other areas of the cerebral cortex and are perceived The supercell clusters do “instant analysis” that helps us act

3. Parallel processing Brain divides scenes into subdimensions and processes them at the same time (Different brain areas become active in response to the same retinal stimulation) This makes up for the “slowness” of individual neural impulses E.g. face recognition requires many different processes, but they occur simultaneously and information is then integrated

4. Color Vision Young-Helmholtz Trichromatic Theory Retina has three types of cones, each sensitive to a color (red, green, blue) Color deficiency = one type of cones doesn’t function Opponent-process theory Some neurons are turned “on” by one color and “off” by an opposing color We can’t see both colors at once This explains afterimages Red/green; blue/yellow; black/white

5. Color Constancy The color we see is based on an object’s surroundings Familiar objects seem to remain the same color even when the wavelength actually changes Top-down processing