Wavelength
Distance from the peak of one light or soundwave to The peak of the next. Electromagnetic wavelengths Mary from the short glimpse of cosmic rays to the long process of radio transmission
Hue
The dimension of the color that is determined by the wavelength of light what we know as the color means blue green and so forth
intensity
The amount of energy and a light or soundwave, which we perceive as brightness or loudness, as determined by the waves amplitude.
Pupil
The adjustable opening in the center of the eye through which light enters.
Iris
A ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening.
Retina
The transparent structure behind the pupil that changes shape to help focus images on the retain.
Accommodation
The process by which the eyes lens changes shape to focus near or far objects on the retina
Rods
Retinal receptors that detect black, white, and gray; Necessary for Peripheral and twiggy light bison when cones detect fine detail and given rise to color senstations.
Cones
Retinal receptor cells that are concentrated near the center of the retain year and the function in daylight or in well lit conditions. The cones detect fine detail and give rise to color sensations
Optic nerve
the nerve that carries neural impulses from the eye to the brain
Blind spot
the point at which the optic nerve leaves the eye, creating a "blind" spot because no receptor cells are located there
fovea
The central focal point in the retina, around which the eye's cones cluster.
Feature detectors
nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement
Parallel processing
The processing of several aspects of a problem simultaneously; the brain's natural mode of information processing for many functions, including vision. Contrasts with the step-by-step (serial) processing of most computers and of conscious problem solving.
Young Helmholtz trichromatic (three color) theory
The theory that the retina contains three different color receptors-one most sensitive to red, one to green, one to blue-which wen stimulated in combination can produce the percetion of any color.
Opponent process theory
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
Gestalt
an organized whole. Gestalt psychologists emphasized our tendency to integrate pieces of information into meaningful wholes.
Figure-ground
the organization of the visual field into objects (the figures) that stand out from their surroundings (the ground).
Grouping
the perceptual tendency to organize stimuli into coherent groups
Depth perception
the ability to see objects in three dimensions although the images that strike the retina are two-dimensional; allows us to judge distance
Visual cliff
a laboratory device for testing depth perception in infants and young animals
Binocular cues
depth cues, such as retinal disparity, that depend on the use of two eyes
Retinal disparity
a binocular cue for perceiving depth; by comparing images from the two eyeballs, the brain computes distance - the greater the disparity (difference) between the two images, the close the object
Monocular cues
depth cues, such as interposition and linear perspective, available to either eye alone
Phi phenomenon
an illusion of movement created when two or more adjacent lights blink on and off in quick succession
Perceptual constancy
perceiving objects as unchanging (having consistent lightness, color, shape, and size) even as illumination and retinal images change
Color constancy
perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object
Perceptual adaptation
in vision, the ability to adjust to an artificially displaced or even inverted visual field