analysis that begins with the sensory receptors and works up to the brain's integration of sensory information
information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations
the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment
the minimum stimulation needed to detect a particular stimulus 50 percent of the time
the minimum difference between two stimuli required for detection 50 percent of the time. We experience the difference threshold as a just noticeable difference. (Also called just noticeable difference or jnd.)
diminished sensitivity as a consequence of constant stimulation
the focusing of conscious awareness on a particular stimulus, as in the cocktail party effect
A ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening.
the adjustable opening in the center of the eye through which light enters
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.
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
conversion of one form of energy into another. In sensation, the transforming of stimulus energies, such as sights, sounds, and smells, into neural impulses our brains can interpret.
the process by which the eye's lens changes shape to focus near or far objects on the retina
the transparent structure behind the pupil that changes shape to help focus images on the retina
further images are blurry, image focused before retina, eyeball is long
closer images are blurry, image focused beyond retina, eyeball is short
retinal receptors that detect black, white, and gray; necessary for peripheral and twilight vision, when cones don't respond
the point at which the optic nerve leaves the eye creating a "blind" spot because no receptor cells are located there
the central focal point in the retina, around which the eye's cones cluster
Young-Helmholtz trichromatic theory
the theory that the retina contains three different 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. (Myers Psychology 8e p. 212)
cannot see color possess one type of cone
A person who is sensitive to only two of the three wavelengths of light- most can't distinguish RED-GREEN
A person with normal color vision
after you star at someting long enough and then stare at something that is blank you will see their opposite colors (after images)
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
the system for sensing the postion and movement of individual body parts.