front 1 wavelength | back 1 the distance from the peak of one light or sound wave to the peak of the next. Electromagnetic wavelengths vary from the short blips of gamma rays to the long pulses of radio transmission |
front 2 hue | back 2 the dimension of color that is determined by the wavelength of light; what we know as the color names blue, green, and so forth |
front 3 intensity | back 3 the amount of energy in a light wave or sound waves, which influences what we perceive as brightness or loudness. Intensity is determined by the wave's amplitude (height) |
front 4 retina | back 4 the light-sensitive inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual information |
front 5 accomodation | back 5 the process by which the eye's lens changes shape to focus near or far objects on the retina |
front 6 rods | back 6 retinal receptors that detect black, white, and gray, and are sensitive to movement; necessary for peripheral and twilight vision, when cones don't respond |
front 7 cones | back 7 retinal receptors that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. Cones detect fine detail and give rise to color sensations |
front 8 optic nerve | back 8 the nerve that carries nerve impulses from the eye to the brain |
front 9 blind spot | back 9 the point at which the optic nerve leaves the eye, creating a "blind" spot because no receptor cells are located there |
front 10 fovea | back 10 the central focal point in the retina, around which the eye's cones cluster |
front 11 Young-Helmholtz trichromatic (three-color) theory | back 11 the theory that the retina contains three different types of color receptors- one most sensitive to red, one to green, one to blue- which, when stimulated in combination, can produce the perception of any color |
front 12 opponent-process theory | back 12 the theory that opposing retinal processes (red-green, yellow-blue, white-black) enable color vision. For example, some cells are stimulated by green and inhibited by red; others are stimulated by red and inhibited by green |
front 13 feature detectors | back 13 nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement |
front 14 parallel processing | back 14 processing many aspects of a problem simultaneously; the brain's natural mode of information processing for many functions |
front 15 gestalt | back 15 an organized whole. Gestalt psychologists emphasized our tendency to integrate pieces of information into meaningful wholes |
front 16 figure-ground | back 16 the organization of the visual field into objects (the figures) that stand out from their surroundings (the ground) |
front 17 grouping | back 17 the perceptual tendency to organize stimuli into coherent groups |
front 18 depth perception | back 18 the ability to see objects in three dimensions although the images that strike the retina are two-dimensional; allows us to judge distance |
front 19 visual cliff | back 19 a laboratory device for testing depth perception in infants and young animals |
front 20 binocular cue | back 20 a depth cue, such as retinal disparity, that depends on the use of two eyes |
front 21 retinal disparity | back 21 a binocular cue for perceiving depth. By comparing retinal images from the two eyes, the brain computes distance- the greater the disparity (difference) between the two images, the closer the object |
front 22 monocular cue | back 22 a depth cue, such as interposition or linear perspective, available to either eye alone |
front 23 phi phenomenon | back 23 an illusion of movement created when two or more adjacent lights blink on and off in quick succession |
front 24 perceptual constancy | back 24 perceiving objects as unchanging (having consistent color, brightness, shape, and size) even as illumination and retinal images change |
front 25 perceptual adaptation | back 25 the ability to adjust to changed sensory input, including an artificially displaced or even inverted visual field |