ap psych ch 6

prospopagnosia

face blindness

phonagnosia

voice blindness, an inability to recognize familiar voices

sensation

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

sensory receptors

sensory nerve endings that respond to stimuli

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

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

all our senses…

• receive sensory stimulation, often using specialized receptor cells

• transform that stimulation into neural impulses

• deliver the neural information to our brain

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 brain can interpret

psychophysics

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

absolute thresholds

the minimum stimulus energy needed to detect a particular stimulus 50% of the time

signal detection theory

a theory predicting how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise). assumes there is no single absolute threshold and that detection depends partly on a person’s experience, expectations, motivation, and alertness.

subliminal

below one’s absolute threshold for conscious awareness

difference threshold

minimum difference between two stimuli required for detection 50% of the time. we experience the difference threshold as a just noticeable difference (jnd)

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)

sensory adaptation

diminished sensitivity as a consequence of constant stimulation

perceptual set

a mental predisposition to perceive one thing and not another

schemas

concepts that organize and interpret unfamiliar information through experience

wavelength

the distance from the peak of one light or sound wave to the peak of the next. electromagnetic wavelengths vary from the short blips of gamma rays to the long pulses of radio transmission. determines hue.

hue

the dimension of color that is determined by the wavelength of light. what we know was the color names blue, green, and so on forth

amplitude

• light wave’s height; determines its intensity and brightness (bright vs. dull colors)

• sound waves: determines their perceived loudness

intensity

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

frequency

the number of complete wavelengths that can pass a point in a given time, depends on the wavelength.

• shorter wavelength, higher frequency, bluish colors vs. longer wavelength, lower frequency, reddish colors

• in sound waves, determines the pitch (a tone’s experienced highness or lowness). longer waves = lower frequency = lower pitch

cornea

bends light to help provide focus, where light enters the eye. the soft, outer, protective covering of the eye

pupil

a small adjustable opening that light passes. regulates the amount of light entering the eye; full dark adaptation takes about 30 minutes and light adaptation about 1 minute

iris

surrounds the pupil and controls its size, a colored muscle that dilates or constricts in response to light intensity. the colored part of the eye

lens

the curvature and thickness changes to bring nearby or distant objects into focus on the retina. focuses light rays into an image on your retina

retina

the light-sensitive inner surface of the eye, containing the receptor rods (detect brightness contrasts) and cones (detect color) plus layers of neurons that begin the processing of visual information. a multilayered tissue on the eyeball’s sensitive inner surface

accommodation

the process by which the lens changes its curvature and thickness to focus light rays into an image on your retina

rods

retinal receptors that detect black, white, and gray, and are sensitive to movement; are necessary for peripheral and twilight vision, when cones don’t respond. located around the retina’s outer regions, combine their faint energy output and funnel it into a single bipolar cell

cones

retinal receptors that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. cones detect fine detail and give rise to color sensations. many transmit their own message to a single bipolar cell.

bipolar cells

activate ganglion cells, sparked by chemical reactions in the receptor cells

ganglion cells

their axons twine together to form the optic nerve

optic nerve

the nerve that carries neural impulses from the eye to the brain, information highway from the eye to the brain, transmits visual information to the brain

blind spot

where the optic nerve leaves to the back of the eye, creating a “blind” spot because no receptor cells are located there

fovea

the central focal point in the retina, around which the eye’s cones cluster, an area of the retina that contains all cones and no rods

young-helmholtz trichromatic theory

the theory that the retina contains three different types of 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

color-deficient vision

lack functioning red- or green-sensitive cones, monochromatic or dichromatic instead of trichromatic

afterimages

stare at a green square for a while and then look at a white sheet of paper, you will see red, green’s opponent color

opponent-process theory

the theory that opposing retinal processes (red-green, yellow-blue, white-blac) enable color vision. for ex: some cells are stimulated by green and inhibited by red; others vice versa. proposed by ewald hering

feature detectors

nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement, activated to determine lines, curves, motion and other features of the object. receive information from ganglion cells

supercell clusters

teams of cells respond to complex patterns

fusiform face area

enables you to perceive faces and recognize them from varied viewpoints in the right temporal lobe

binding

integrating the separate but parallel work of different visual teams (motion,form,depth,color)

grandmother cell

hypothetical neuron that responds only to a highly specific stimulus

blindsight

patients with damaged visual cortex who report seeing nothing but their visual intuition typically offers the correct response

gestalt

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

figure-ground

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

grouping

the perceptual tendency to organize stimuli into coherent groups

proximity

grouping nearby figures together

continuity

perceiving smooth, continuous patterns rather than discontinuous ones

closure

filling in gaps to create a complete, whole object

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

a model of a cliff with a “drop-off” area that was actually covered by sturdy glass, used for testing depth perception in infants and young animals

binocular cues

a depth cue, such as retinal disparity, that depends on the use of two eyes, used to judge the distance of nearby objects

retinal disparity

a binocular cue for perceiving depth. by comparing retinal images from the two eyes, the brain computes distance-the greater the disparity between the two images, the closer the object

monocular cues

depth cues available to each eye separately. incl. relative height/size, interposition, linear perspective, light and shadow, and relative motion

stroboscopic movement

when our brain perceives a rapid series of slightly varying images as continuos movement (flipbook)

phi phenomenon

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

perceptual constancy

perceiving objects as unchanging (having consistent color, brightness, shape, and size) even as illumination and retinal images change

color constancy

when a familiar object may be perceived as having a consistent color regardless of the changing wavelengths reflecting off its surface

brightness/lightness constancy

perceiving an object as having a constant brightness even as its illumination varies. depends on relative luminance

relative luminance

the amount of light an object reflects relative to its surroundings

shape constancy

perceiving the form of familiar objects as constant even while our retinas receive changing images of them

size constancy

perceiving an object as having a constant size even while our distance from it varies

moon illusion

the moon looks up to 50% larger when near the horizon than when high in the sky. monocular cues to an object’s distance make the horizon moon seem farther away, and our brain assumes it must be larger than the sky moon

immanuel kant

maintained that knowledge comes from our inborn ways of organizing sensory experiences; we come equipped to process sensory information

john locke

argued that through our experiences we also learn to perceive the world

critical period

an optimal period when exposure to certain stimuli or experiences is required. once passed, sensory restrictions later in life do no permanent harm

perceptual adaptation

the ability to adjust to changed sensory input, including an artificially displaced or even inverted visual field

audition

the sense or act of hearing

decibels

unit of measurement for sounds; 0 decibels represent the absolute threshold for hearing, prolonged exposure to sounds above 8 decibels can produce hearing loss

eardrum

sound waves cause this tight membrane to vibrate

outer ear

funnels sound waves to the eardrum

middle ear’s bones (hammer, anvil, stirrup)

amplifies and relays the eardrum’s vibrations through the oval window into the fluid-filled cochlea

cochlea’s membrane

(inner ear) vibrates when incoming vibrations pass through from the cochlea, causes ripples in the basilar membrane

basilar membrane

(inner ear) lined with hair cells, ripples from the cochlea’s membrane’s vibration

hair cells in the basilar membrane

triggers adjacent nerve fibers that send neural messages through the thalamus to the auditory cortex of the temporal lobe

cochlea

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

middle ear

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

inner ear

contains the cochlea, semicircular canals, and vestibular sacs

oval window

the cochlea’s membrane-covered opening

auditory nerve

made up of axons of nerve cells adjacent to the hair cells

cilia

proteins on the tip of a hair cell that trigger a neural response

sensorineural hearing loss (nerve deafness)

hearing loss caused by damage to the cochlea’s receptor cells or to the auditory nerves; the most common form of hearing loss. w/ auditory nerve damage, people may hear sound but have trouble discerning what someone is saying

conduction hearing loss

less common form of hearing loss; caused bu damage to the mechanical system that conducts sound waves to the cochlea

cochlear implant

only way to restore hearing from nerve deafness; a device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threated into the cochlea

number of activated hair cells

how your brain interprets loudness

place theory

the theory that links the pitch we hear with the place where the cochlea’s membrane is stimulated; explains how we hear high-pitched but not low-pitched

frequency/temporal theory

the theory that the rate of nerve impulses travelling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch. ex: if a sound wave has a frequency of 100 waves/second, then 100 pulses/second travel up the auditory nerve. best explains low pitches.

volley principle

related to the frequency/temporal theory: an individual neuron can’t fire faster than 1000 times/second. so, neural cells can alternate firing & by firing in rapid succession they can achieve a combined frequency above 1000 waves/second.

four basic and distinct skin senses

pressure, warmth, cold, pain; our sense of touch is a mix of these

nociceptors

sensory receptors that detect hurtful temperatures, pressure, or chemicals in your skin, muscles, and organs. sends an impulse to the spinal cord, which passes the message to the brain, which interprets the signal as 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

phantom limb sensations

7 in 10 people feel pain or movement in nonexistent limbs

tinnitus

the phantom sound of ringing in the ears that’s accompanied by auditory brain activity, people with hearing loss often experience the sound of silence

endorphins

our brain releases this natural painkiller in response to severe pain or even vigorous exercise

hypnosis

social interaction in which one person (the hypnotist) suggests to another (the subject) that certain perceptions, feelings, thoughts, or behaviors will spontaneously occur

social influence theory

hypnosis is a by-product of normal social and mental processes. hypnotized people begin to feel and behave in ways appropriate for “good hypnotic subjects”

dissociation theory

hypnosis is a special dual-processing state of dissociation-a split between different levels of consciousness. explains posthypnotic suggestions and why people hypnotized for pain relief may show brain activity in areas that receive sensory information but not in areas that normally process pain-related information