PY101 CH.4
Terms
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- the stimula- tion of sense organs
- sensation
- the selection, organization, and interpretation of sensory input.
- perception
- —the study of how physi- cal stimuli are translated into psychological ex- perience
- psychophysics
- the minimum stimulus intensity that an organism can detect
- absolute threshold
- the smallest difference in stimu- lus intensity that a specifi c sense can detect
- just noticeable difference
- proposes that the detection of stimuli involves decision processes as well as sensory processes, which are both infl uenced by a variety of factors besides stimulus intensity
- signal detection theory
- the registration of sensory input without conscious awareness
- subliminal perception
- a gradual decline in sensi- tivity to prolonged stimulation
- sensory adaptation
- the opening in the center of the iris that permits light to pass into the rear cham- ber of the eye.
- pupil
- pecialized visual receptors that play a key role in daylight vision and color vision
- cones
- a tiny spot in the center of the retina that contains only cones; visual acuity is greatest at this spot.
- fovea
- specialized visual receptors that play a key role in night vision and peripheral vision.
- rods
- the process in which the eyes become more sensitive to light in low illumination.
- dark adaptation
- the process whereby the eyes become less sensitive to light in high il- lumination.
- light adaptation
- when neural activity in a cell opposes activity in surrounding cells.
- lateral antagonism
- the point at which the optic nerves from the in- side half of each eye cross over and then project to the opposite half of the brain
- optic chiasm
- involves simultane- ously extracting different kinds of information from the same input
- parallel processing
- neurons that respond selectively to very specifi c features of more complex stimuli
- feature detectors
- works by removing some wavelengths of light, leaving less light than was originally there
- subtractive color mixing
- works by superimposing lights, putting more light in the mixture than exists in any one light by itself
- additive color mixing
- holds that the human eye has three types of receptors with differing sensitivities to different light wave- lengths
- trichomatic theory
- pairs of colors that pro- duce gray tones when mixed together.
- complementary colors
- a visual image that per- sists after a stimulus is removed
- after image
- holds that color perception depends on receptors that make antagonistic responses to three pairs of colors
- opponent process of theory
- which involves the failure to see visible objects or events because one’s attention is focused elsewhere
- inattentional blindness
- the pro- cess of detecting specifi c elements in visual input and assembling them into a more complex form
- feature analysis
- a progression from individual elements to the whole
- bottom up processing
- a progression from the whole to the elements
- top down processing
- the perception of contours where none actually exis
- subjective contours
-
the illusion of move- ment created by presenting visual stimuli in rapid succession
- phi phenomenon
- stimuli that lie in the distance (that is, in the world outside the body
- distal stimuli
- stimulus energies that im- pinge directly on sensory receptors
- proximal stimuli
- an inference about which distal stimuli could be responsible for the proxi- mal stimuli sensed.
- perceptual hypothesis
- clues about distance based on the differ- ing views of the two eyes.
- binocular depth cues
- refers to the fact that objects within 25 feet project images to slightly different loca- tions on the right and left retinas, so the right and left eyes see slightly different views of the object
- retinal disparity
-
involves sensing the eyes converging toward each other as they focus on closer objects.
- convergence
- cues are clues about distance based on the image in either eye alone
- monocular depth
- involves images of objects at different distances moving across the retina at different rate
- motion parallax
- clues about distance that can be given in a flat picture
- pictorial depth cues
- a tendency to experience a stable perception in the face of continually changing sensory input
- perceptual constancy
- objects that can be repre- sented in two-dimensional pictures but cannot exist in three-dimensional space
- imposible figures
- which runs the length of the spiraled cochlea, holds the auditory receptors
- basilar membrane
- holds that perception of pitch corresponds to the vibration of different portions, or places, along the basilar membrane
- place theory
-
that perception of pitch corresponds to the rate, or frequency, at which the entire basilar membrane vibrates.
- frequency theory
- locating the source of a sound in space.
- auditory localization
- the sen- sory system for taste
- gustatory system
- holds that incoming pain sensations must pass through a “gate†in the spinal cord that can be closed, thus blocking ascending pain signals
- gate control theory