Psychology Unit 3

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

Bottom-Up Processing

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

Top-Down Processing

the use of preexisting knowledge to organize individual features into a unified whole

Selective Attention

the focusing of conscious awareness on a particular stimulus

Cocktail party effect

Ability to concentrate on one voice amongst a crowd

Stroop Effect

delay in reaction time when color of words on a test and their meaning differ

Selective Inattention

what we are not focused on, what we do not notice

Inattentional Blindness

failing to see visible objects when our attention is directed elsewhere

Change Blindness

failing to notice changes in the environment

Transduction

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.

Psychophysics

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

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)

Signal Detection Theory

the response to a stimulus depends both on a person's sensitivity to the stimulus in the presence of noise and on a person's response criterion

Subliminal Perception

the processing of information by sensory systems without conscious awareness

Sensory Adaption

diminished sensitivity as a consequence of constant stimulation

Perceptual Set

a mental predisposition to perceive one thing and not another

ESP

the controversial claim that perception can occur apart from sensory input; includes telepathy, clairvoyance, and precognition

Parapsychology

the study of paranormal phenomena, including ESP and psychokinesis

Wavelength

the distance from the peak of one light or sound wave to the peak of the next

Hue

color

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

Cornea

The clear tissue that covers the front of the eye

Pupil

the adjustable opening in the center of the eye through which light enters

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

Aqueous Humor

fluid in the eye, found between the cornea and the lens

Vitreous Humor

jellylike substance found behind the lens in the posterior cavity of the eye that maintains its shape

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

Accomodation

When the lens flips the image before passing through the retina

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.

Fovea

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

Optic Nerve

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

Peripheral Vision

ability to see objects as they come into the outer edges of the visual field

Tunnel Vision

loss of peripheral vision

Blind Spot

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

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.

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

Afterimage

A visual image that persists after a stimulus is removed.

Myopia

nearsightedness

Presbyopia

farsightedness

Astigmatism

a condition in which the eye does not focus properly because of uneven curvatures of the cornea

Glaucoma

increased intraocular pressure results in damage to the retina and optic nerve with loss of vision

feature detectors

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

parallel processing

feature detectors can react to visual stimuli simultaneously

gestalt

an organized whole

figure-ground

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

proximity

when the distance between things make us see them in groups

similarity

the tendency to perceive things that look similar to each other as being part of the same group

continuity

the tendency to perceive things as simply as possible with a continuous pattern rather than with a complex, broken-up pattern

connectedness

spots, lines, and areas are seen as unit when connected

closure

the tendency to complete figures that are incomplete

depth perception

the ability to see objects in three dimensions although the images that strike the retina are two-dimensional; allows us to judge distance

visual cliff

process to tell if a baby has a sense of depth

binocular cues

depth cues that depend on the use of two eyes

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.

convergence

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

monocular cues

depth cues available to either eye alone

linear convergence

when staring at parallel lines like railroad tracks, they appear to converge in the distance even though they go straight

interposition

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

relative size

perception that occurs when objects that a person expects to be of a certain size appear to be small and are, therefore, assumed to be much farther away

relative height

we perceive objects higher in our field of vision as farther away

relative clarity

hazy object seen as more distant

light and shadow

shading produces a sense of depth consistent with our assumption that light comes from above

motion parallax

a depth cue in which the relative movement of elements in a scene gives depth information when the observer moves relative to the scene

phi phenomenon

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

perceptual constancy

perceiving objects as unchanging even as illumination and retinal images change

color constancy

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

brightness constancy

the tendency to perceive the apparent brightness of an object as the same even when the light conditions change

shape constancy

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

size constancy

the tendency to interpret an object as always being the same actual size, regardless of its distance

audition

the sense or act of hearing

sound waves

Successive pressure variations in the air that vary in amplitude and wavelength.

amplitude

Height of a wave

frequency

the number of complete wavelengths that pass a point in a given time

pitch

How high or low a sound is

pinna

outer ear

tympanic membrane

a membrane forming part of the organ of hearing, which vibrates in response to sound waves. In humans and other higher vertebrates it forms the eardrum, between the outer and middle ear.

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

inner ear

the innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs

cochlea

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

auditory nerve

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

sensorineural hearing loss

hearing loss caused by damage to the cochlea's receptor cells or to the auditory nerves

conduction hearing loss

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

cochlear implant

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

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

touch

sensed by pressure, warmth, cold, and pain

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.

sweet

energy source

salty

sodium essential to physiological processes

sour

potentially toxic acid

bitter

potential poisons

umami

proteins to grow and repair tissue

olfaction

sense of smell

kinesthesia

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

vestibular sense

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