Sensation and Perception Review

absolute threshold

The minimal amount of energy required to produce any sensation, 50 percent of the time.

binocular cues

visual messages/cues that require two eyes

blind spot

Place on the retina out where the optic nerve leaves the eye, no receptors (rods/cones) are located here

cones

Visual receptor cells; located in retina; works best in bright light; responsible for viewing color; greatest density in the fovea.

difference threshold

Just Noticeable Difference (JND); the smallest change in stimulation that you can detect 50% of the time; differs from one person to the other (and from moment to moment); tells us the flexibility of sensory systems - Basis of Weber's Law

bottom-up processing

Starts with basic sensory information to construct a perception - not based on any experience.

top-down processing

Constructing perceptions based on our experiences and expectations

selective attention

The focusing of conscious awareness on a particular stimulus, like the cocktail effect (notice your name in a crowd)

inattentional blindness

failing to see visible objects when our attention is directed elsewhere

Priming

Refers to the unconscious influence of exposure to a stimulus (the "prime") on a person's thoughts or behaviors. 

change blindness

failing to notice changes in the environment.

hue

color, or aspects of colors

Iris

the color part of the eye; made of muscle that contracts/relaxes to control the size of the people allowing light to enter the eye

Lens

transparent part of the eye behind the iris; focuses light on the retina (accommodation); change shape to focus on objects

psychophysics

The study of relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience of them.

signal detection theory

States that circumstances, experiences, expectations affect our thresholds. Example- hearing the faint sound of the new born while sleeping but not noticing the loud thunder outside.

subliminal perception

Sensory information that is detected without our conscious knowledge

sensory adaptation

Diminished sensitivity as a consequence of constant stimulation.

habituation

decreasing responsiveness with repeated stimulation. As infants gain familiarity with repeated exposure to a visual stimulus, their interest wanes and they look away sooner

transduction

Conversion of one form of energy into another. In sensation, the transforming of stimulus energies into neural impulses.

opponent-process theory

created by Edward Hering; alternative theory used to explain after images; suggest that the retina contains three pairs color receptors or cones-yellow-blue, red-green, black-white; pairs work in opposition (thalamus)

wavelength

The distance from the peak of one light or sound wave to the peak of the next. Determines the hue we see. longer waves/red, shorter waves/blue

optic nerve

bundle of axons from ganglion cells that carries messages from the eye to the brain

bipolar cells of retina

Bipolar cells compose an intermediate layer of connecting neurons in the retina.

myopia

nearsightedness - unable to see things that are far away

hyperopia

farsightedness - unable to see things that are up close

Intensity

The amount of energy in a light or sound wave, which we perceive as brightness or loudness, as determined by the wave's amplitude.

feature detectors

nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement.

Gestalt grouping principles

We tend to group objects according to the following: proximity, similarity, closure, continuity and connectedness

proximity

group nearby figures together

similarity

group similar figures together

closure

we fill in gaps to create a complete, whole object

monocular cues

depth cues, such as interposition and linear perspective, available to either eye alone. Only need one eye to perceive it.

linear perspective

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

interposition cue

if one object partially blocks our view of another, we perceive it as closer

relative size

a monocular cue for perceiving depth; the smaller retinal image is farther away

texture gradient (monocular cue)

a gradual change from a coarse, distinct texture to a fine, indistinct texture signals increasing distance. Objects far away appear smaller and more densely packed

relative clarity (monocular cue)

hazy object seen as more distant

light and shadow (monocular cue)

brighter objects are perceived as being closer than darker objects

perception

the mental process of sorting, identifying, and arranging raw sensory data into meaningful patterns

parallel processing

The processing of several aspects of a problem simultaneously; form, depth, color and motion

pupil

small opening in the center of the iris - the hole in the eye to allow light to enter.

retina

the light-sensitive inner lining of the back of the eyeball; contains receptor cells (rods/cones) Allows you to see - it's the "brain" of the eye.

retinal disparity

binocular distance cue; based on the overlay of two retinal fields when both eyes focus on one object

rods

visual receptor cell; located in retina; respond to varying degrees of light and dark; responsible for night vision and peripheral vision

color blindness

Inability to distinguish some or all colors due to a damaged cone.

perceptual accommodation

in perception, the ability to adjust to an idea or mind set

sensation

the raw data of experience; sensory stimulation; example are eyes only register light energy and ears only register wave energy

synesthesia

describing one kind of sensation in terms of another ("a loud color", "a sweet sound")

fovea

The central focal point in the retina, around which the eye's cones cluster.

size constancy

the perception of an object as the same size regardless of the distance from which it is viewed.

Weber's law

Ernst Weber; the principle that accounts for how one notices the difference threshold (JND) for any change must be proportional.

Sensory interaction

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

perceptual consistancy

perceiving objects as unchanging (having consistent shapes, size, lightness, and color) even as illumination and retinal images change.

Herman von Helmholtz

Theorist who both aided in the development of the trichromatic theory of color perception and Place theory of pitch perception.

depth perception

Ability to see objects in three dimension although the image that strike the retina are two-dimensional; allows us to judge distance

Visual cliff

Laboratory device for testing depth perception in infants and young animals. Study done by Eleanor Gibson

Phi Phenomenon

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

Color constancy

Perceiving familiar objects as having consistent color, even if changing illumination alters the wave-lengths reflected by the object

Perceptual adaptation

In vision, the ability to adjust to an artificially displaced or even inverted visual field

Perceptual set

A mental predisposition to perceive one thing and not another

Accommodation

Process by which the eye lens changes shape to focus near or far objects on the retina

Figure Ground

The organization of the visual field into objects that stand out from their surroundings.

Cornea

the transparent outer covering of the eye

papillae

taste buds

audition

the sense of hearing

frequency

the number of complete wavelengths that pass a point in a given time - determines the pitch of a sound

relative motion

As we move, objects that are actually stable may appear to move

relative luminance (brightness)

the amount of light an object reflects relative to its surroundings

shape constancy

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

Ames room illusion

A perceptual misinterpretation involving a trapezium shaped room which appears rectangular when viewed through a peephole using only one eye and people appear small or large, depending on where they stand in the room.

perceptual adaptation

in vision, the ability to adjust to an artificially displaced or even inverted visual field

middle ear

the chamber between the eardrum and cochlea containing three tiny bones (hammer, anvil, and stirrup) that concentrate the vibrations of the eardrum on the cochlea's oval window

Ossicles

three tiny bones in the middle ear

(malleus, incus, stapes)

Pinna

the visible part of the ear

cochlea

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

oval window

membrane at the entrance to the cochlea through which the ossicles transmit vibrations

decibles

A unit used to measure the loudness of a sound.

basilar membrane

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

auditory nerve

the nerve that carries impulses from the inner ear to the brain, resulting in the perception of sound

auditory cortex

the area of the temporal lobe responsible for processing sound information

sensorineural hearing loss

hearing loss caused by damage to the cochlea's receptor cells or to the auditory nerves; also called nerve deafness - Only corrected with a cochlear implant

cochelar implant

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

conduction hearing impairment

refers to problems with the mechanics of the outer or middle ear and means that sound vibrations cannot be passed from the eardrum to the cochlea - corrected with a hearing aid

place theory

in hearing, the theory that links the pitch we hear with the place 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

volley principle for hearing

clusters of neurons take turns firing in a sequence of rhythmic volleys, and that pitch depends on the frequency of these volleys.

sound shadow effect

The amount of sound reflected also depends on the size of the object it encounters

tactile sense

sense of touch

phantom limb sensation

patients who have had a limb amputated may still experience sensations such as itching, pressure, tingling, or pain as if the limb were still there

touch sensations

pressure, warmth, cold, pain

Endorphins

natural, opiate-like neurotransmitters linked to pain control

pain

an unpleasant sensory experience associated with actual or potential tissue damage

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.

Placebos

Inactive substances, not real medications, that are used to test the effectiveness of drugs.

Gustation

sense of taste

taste sensations

sweet, sour, salty, bitter, umami, oleogustus

sweet

energy source

salty

sodium essential to physiological processes