Psyc201 Chapter 5: Sensation And Perception

Front 1

absolute threshold

Back 1

The lowest intensity at which a stimulus can be detected 50 percent of the time.

Front 2

amplitude

Back 2

The vertical size of the sound wave, which gives rise to the perception of loudness and is measured in terms of decibels.

Front 3

basilar membrane

Back 3

A membrane that runs the length of the cochlea and contains the organ of Corti and its sound receptor hair cells.

Front 4

binocular depth cues

Back 4

Depth cues that require the use of both eyes.

Front 5

binocular disparity

Back 5

The binocular depth cue produced by the projection of slightly different images of an object on the retinas of the two eyes.

Front 6

bottom-up processing

Back 6

Perceptual processes that begin with the analysis of individual elements of the stimulus and work up to the brain’s integration of them into a unified perception.

Front 7

cochlea

Back 7

A small coil-shaped structure of the inner ear that contains the receptors for sound.

Front 8

conduction deafness

Back 8

Hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea.

Front 9

cones

Back 9

Photoreceptors in the retina that function best in bright light and are differentially sensitive to red, green, or blue wavelengths.

Front 10

convergence

Back 10

A binocular depth cue produced by the muscles that rotate the eyes as they focus on nearby objects.

Front 11

critical periods

Back 11

Limited time periods during which plasticity can occur as a result of experience or in response to injury; in development, a time period in which exposure to particular kinds of stimulation is required for normal growth to occur.

Front 12

dark adaptation

Back 12

The progressive increase in brightness sensitivity that occurs over time as photopigments regenerate themselves during exposure to low levels of illumination.

Front 13

decibel (dB)

Back 13

A logarithmic measure of sound intensity.

Front 14

decision criterion

Back 14

In signal detection theory, the potentially changing standard of how certain a person must be that a stimulus is present in order to report its presence.

Front 15

difference threshold

Back 15

The smallest difference between two similar stimuli that people can detect; also called the just noticeable difference (jnd).

Front 16

dual-process theory

Back 16

A modern theory of color vision that combines the trichromatic and opponent-process theories. Light waves are coded by red-, blue-, and green-sensitive cones in the retina and by opponent processes thereafter in the visual system.

Front 17

endorphins

Back 17

Natural opiate-like substances that are involved in pain reduction.

Front 18

feature detectors

Back 18

Sensory neurons that respond to particular features of a stimulus, such as its shape, angle, or color.

Front 19

figure-ground relations

Back 19

Perceptual organization in which a focal stimulus is perceived as a figure against a background of other stimuli.

Front 20

fovea

Back 20

A small area in the center of the retina that contains only cones and where visual acuity is greatest.

Front 21

frequency

Back 21

In audition, the number of cycles per second in a sound wave that is responsible for the pitch of the sound; the measure of frequency is the hertz (Hz), which equals one cycle per second.

Front 22

frequency theory of pitch perception

Back 22

Maintains that the number of nerve impulses sent to the brain by the hair cells of the cochlea corresponds to the frequency of the sound wave; this theory is accurate at low frequencies.

Front 23

gate control theory

Back 23

A theory of pain that postulates the existence of gating mechanisms in the spinal cord and brain that can increase or decrease the experience of pain by regulating the flow of pain impulses to the brain.

Front 24

Gestalt laws of perceptual organization

Back 24

The notion that people group and interpret stimuli in accordance with similarity, proximity, closure, and continuity.

Front 25

gustation

Back 25

The sense of taste.

Front 26

Hering’s opponent-process theory

Back 26

The color vision theory stating that the retina contains three sets of color receptors that respond differentially to red-green, blue-yellow, and black-white; the opponent processes that result can produce a perception of any hue.

Front 27

hertz (Hz)

Back 27

The measure of sound-wave frequency as cycles per second.

Front 28

illusions

Back 28

Incorrect perceptions based on false perceptual hypotheses that often result from constancies that do not apply to the stimuli in question.

Front 29

inattentional blindness

Back 29

The failure of unattended stimuli to register in consciousness.

Front 30

kinesthesis

Back 30

The body sense that provides feedback on the position and movements of our body parts.

Front 31

lens

Back 31

The transparent structure behind the pupil that changes its shape to focus images on the retina.

Front 32

menstrual synchrony

Back 32

The tendency for some women who live together or are close friends to become more similar to one another in the timing of their menstrual cycles over time.

Front 33

monocular depth cues

Back 33

Depth cues that require only one eye; include linear perspective, decreasing size, height in the horizontal plane, texture, clarity, light and shadow, motion parallax, and interposition.

Front 34

nerve deafness

Back 34

Hearing loss caused by damage to the cochlear receptor cells or to the auditory nerve.

Front 35

olfaction

Back 35

The sense of smell

Front 36

olfactory bulb

Back 36

A forebrain structure that receives input from the receptors for the sense of smell.

Front 37

optic nerve

Back 37

The bundle of ganglion cell axons that carries information from the visual receptors to the visual area of the thalamus.

Front 38

organ of Corti

Back 38

Structures embedded in the basilar membrane that contain the hair cell receptors for sound.

Front 39

perception

Back 39

The process of organizing stimulus input and giving it meaning.

Front 40

perceptual constancies

Back 40

The ability to recognize stimulus characteristics—size, color, and so on—under varying conditions.

Front 41

perceptual schema

Back 41

Internal representations that contain the essential features of an object of perception.

Front 42

perceptual set

Back 42

A readiness to perceive a stimulus in a particular way based on expectations, motives, emotions, or beliefs.

Front 43

pheromones

Back 43

Chemical signals found in natural body scents.

Front 44

photopigments

Back 44

Protein molecules within the rods and cones whose chemical reactions when absorbing light result in the generation of nerve impulses.

Front 45

place theory of pitch perception

Back 45

States that sound frequencies are coded in terms of the portion of the basilar membrane where the fluid wave in the cochlea peaks; this theory accounts for perception of frequencies above 4,000 hertz.

Front 46

psychophysics

Back 46

The study of relations between the physical characteristics of stimuli and the sensory experiences they evoke.

Front 47

retina

Back 47

The light-sensitive tissue at the back of the eye that contains the visual receptors.

Front 48

rods

Back 48

Photoreceptors in the retina that function under low levels of illumination and do not give rise to color sensations.

Front 49

sensation

Back 49

The process by which stimuli are detected, transduced into nerve impulses, and sent to the brain.

Front 50

sensory adaptation

Back 50

Diminishing sensitivity to an unchanging stimulus with the passage of time as sensory neurons habituate to the stimulation.

Front 51

sensory prosthetic devices

Back 51

A device for providing sensory input that can, to some extent, substitute for what cannot be supplied by the person’s own sensory receptors.

Front 52

signal-detection theory

Back 52

A theory that assumes that stimulus detection is not based on a fixed absolute threshold but rather is affected by rewards, punishments, expectations, and motivational factors.

Front 53

stroboscopic movement

Back 53

The illusory movement produced when adjacent lights are illuminated and extinguished at specific time intervals.

Front 54

subliminal stimulus

Back 54

Weak stimuli below the perceptual threshold that are not consciously perceived.

Front 55

synesthesia

Back 55

A condition in which stimuli are experienced not only in the normal sensory modality but in others as well.

Front 56

taste buds

Back 56

Chemical receptors for taste in the tongue and in the roof and back of the mouth that are sensitive to the qualities of sweet, sour, salty, and bitter.

Front 57

top-down processing

Back 57

Perceptual processing in which existing knowledge, concepts, ideas, or expectations are applied in order to make sense of incoming stimulation.

Front 58

transduction

Back 58

The conversion of one form of energy into another; in sensation, the process whereby physical stimuli are translated into nerve impulses.

Front 59

vestibular sense

Back 59

he sense of body orientation, or equilibrium.

Front 60

visual acuity

Back 60

he ability to see fine detail.

Front 61

Weber’s law

Back 61

States that to perceive a difference between two stimuli, the stimuli must differ by a constant percentage or ratio.

Front 62

Young-Helmholtz trichromatic theory

Back 62

The color vision theory stating that there are three types of color receptors in the retina— one for red, one for blue, and one for green— and that combinations of activation of these receptors can produce perception of any hue in the visible spectrum.