Sensation and Perception Review- UNIT 3

sensory adaptation

tendency of sensory receptor cells to become less responsive to a stimulus that is unchanging

Habituation

tendency of the brain to stop attending to constant, unchanging information

absolute threshold

the minimum stimulation needed to detect a particular stimulus 50 percent of the time

difference threshold

the minimum difference between two stimuli required for detection 50 percent of the time

Weber's Law

the principle that, to be perceived as different, two stimuli must differ by a constant minimum percentage (rather than a constant amount)

Sensation

the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment

Perception

the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events

Transduction

the transforming of stimulus energies, such as sights, sounds, and smells, into neural impulses our brains can interpret.

Thalamus

the brain's sensory switchboard, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla

cochlea

a coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses

optic nerve

the nerve that carries neural impulses from the eye to the brain

bipolar cells

eye neurons that receive information from the retinal cells and distribute information to the ganglion cells

ganglion cells

In the retina, the specialized neurons that connect to the bipolar cells; the bundled axons of the ganglion cells form the optic nerve.

Fovea

the central focal point in the retina, around which the eye's cones cluster (clearest point of vision)

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.

fusiform gyrus

region of the temporal lobe that responds when faces are present in the visual field

Prosopagnosia

inability to recognize faces

Cornea

the transparent layer forming the front of the eye.

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

trichromatic theory

Visual theory, stated by Young and Helmholtz that all colors can be made by mixing the three basic colors: red, green, and blue; a.k.a the Young-Helmholtz theory.

opponent process theory of color vision

The theory that color vision is the product of opposing pairs of color receptors, red-green, blue-yellow, and black-white; when one member of a color pair is stimulated, the other member is inhibited.

Afterimages

the sensation left over after an image is removed

sensorineural deafness

deafness that usually results from damage to the inner ear or to the auditory nerve

vestibular sense

the sense of body movement and position, including the sense of balance

semicircular canals

three canals within the inner ear that contain specialized receptor cells that generate nerve impulses with body movement

vestibular system

three semicircular canals that provide the sense of balance, located in the inner ear and connected to the brain by a nerve

gate-control theory

the theory that the spinal cord contains a neurological "gate" that blocks pain signals or allows them to pass on to the brain. The "gate" is opened by the activity of pain signals traveling up small nerve fibers and is closed by activity in larger fibers or by information coming from the brain.

chemical senses

Our ability to process the environmental stimuli of smell and taste.

olfactory nerve

the nerve that carries smell impulses from the nose to the brain

conductive deafness (middle-ear deafness)

hearing loss that occurs if the bones of the middle ear fail to transmit sound waves properly to the cochlea

hammer, anvil, stirrup

the three small bones in the middle ear that relay vibrations of the eardrum to the inner ear

basilar membrane

A structure that runs the length of the cochlea in the inner ear and holds the auditory receptors, called hair cells

Intensity (loudness)

Amount of energy in a wave; determined by the amplitude, relates to perceived loudness

high amplitude

bright colors

low amplitude

dull colors

pitch

a tone's experienced highness or lowness; depends on frequency

frequency theory of hearing

the entire basilar membrane acts like a microphone, vibrating as a whole in response to a sound

place theory

in hearing, the theory that links the pitch we hear with the place where the cochlea's membrane is stimulated

cochlear implant

a device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea

kinesthesis

the system for sensing the position and movement of individual body parts

taste

gustation

top-down processing

information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations

bottom-up processing

analysis that begins with the sense receptors and works up to the brain's integration of sensory information

Pheromones

Chemical signals released by an animal that communicate information and affect the behavior of other animals of the same species.

sensory interaction

the principle that one sense may influence another, as when the smell of food influences its taste

Proprioception

our sense of body position

optic chiasm

point at which optic nerve fibers cross in the brain

trichromatic theory of color vision

The theory that there are three kinds of cones in the retina, each of which responds primarily to a specific range of wavelengths

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

Afterimages refer to

the sensation left over after an image is removed.

pitch theory

The theory that links the pitch we hear with the pitch and frequency where the cochlea's membrane is stimulated.

frequency theory

in hearing, the theory that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch

Supertasters

people with heightened sensitivity to all tastes and mouth sensations

nontasters

Not so sensitive to taste, seek out relatively sweeter or fattier foods to maximize taste

Cerebellum

Balance and coordination

blind spot

the point at which the optic nerve leaves the eye, creating a "blind" spot because no receptor cells are located there

figure-ground

the organization of the visual field into objects (the figures) that stand out from their surroundings (the ground).

Gestalt

an organized whole. Gestalt psychologists emphasized our tendency to integrate pieces of information into meaningful wholes.

Continuity

we perceive smooth, continuous patterns rather than discontinuous ones

proximity principle

Gestalt principle of perception that states that parts of a visual stimulus that are close together are perceived as belonging together

convergence

A binocular cue for perceiving depth; the extent to which the eyes converge inward when looking at an object

retinal disparity

a binocular cue for perceiving depth by comparing images from the retinas in the two eyes, the brain computes distance—the greater the disparity (difference) between the two images, the closer the object.

binocular cues

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

monocular cues

depth cues, such as interposition and linear perspective, available to either eye alone

shape constancy

the tendency to interpret the shape of an object as being constant, even when its shape changes on the retina

perceptual set

a predisposition or readiness to perceive something in a particular way

phi phenomenon

an illusion of movement created when two or more adjacent lights blink on and off in quick succession

visual cliff

a laboratory device for testing depth perception in infants and young animals

color constancy

perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object

Perception

the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events

linear perspective

A monocular cue for perceiving depth; the more parallel lines converge, the greater their perceived distance.