s and p psychology

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

lens

the transparent structure behind the pupil that changes shape to help focus images on the retina

Retina

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

accomodation

the process by which the eye's 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 twilight vision, when cones don't respond

Cones

retinal receptor cells that are concentrated near the center of the retina and that 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 many 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 theory

3 corresponding color receptors

(RGB)

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

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

binocular cues

depth cues, such as retinal disparity and convergence, that depend on the use of two eyes

retinal disparity

a binocular cue for perceiving depth

monocular cues

depth cues available to either eye alone