Unit 8 - Sensation and Perception Flashcards
synesthesia
increased communication between sensory regions that results in synesthetes experiencing the world differently
sensation
occurs when receptors in sense organs are activated allowing stimuli to become neural signals in brain
transduction
process of converting outside stimuli into neural impulse
sensory receptors
eyes - light
ears - vibrations
touch - pressure/temperature
taste/smell - chemical substances
Ernst Weber
- study to determine smallest difference between two weights
- Weber’s Law of Just Noticeable Difference
Just Noticeable Difference
smallest difference between two stimuli that’s detectable 50% of the time
Weber’s Law
as stimulus increases, the JND increases
Gustav Fechner
created absolute threshold
absolute threshold
lowest level of stimulation a person can consciously detect 50% of the time stimulation is present
- ## low threshold means person has high detection
subliminal stimuli
stimuli below level of conscious awareness –> just strong enough to activate sensory receptors
subliminal perception
subliminal stimuli act on unconscious mind –> influencing behavior
Vicary
man who did fake subliminal perception ad in movie theater
habituation
brain filters sensory stimulation and “ignores”/prevents conscious attention to stimuli that doesn’t change
- pay less attention to constant stimulus
- brain decides it isn’t important so stops paying attention
- can “snap out of it” instantly
sensory adaptation
process by which constant/unchanging information from sensory receptors is ignored
- pay less attention to constant stimulus
- physical change to sensory receptors
- body adapts physically
- there’s a delay in “snapping out of it”
microsaccades
tiny eye vibrations that keep eyes from adapting to what they see
coding
changing each impulse into the right impulse and sending it to correct place
change blindness
don’t notice changes in environment; selective environment causes this
3 aspects to our perception of light
brightness - determined by amplitude of wave (higher = brighter)
color/hue - determined by length of wave (long wavelengths red, short wavelengths blue)
saturation - purity of color people perceive (highly saturated red has only red wavelengths and less saturated red can have mixture of wavelengths)
refraction
light bends as it passes through substances of different densities
cornea
covers surface of eye; protects eye; focuses light coming into eye
aqueous humor
continually replenished and supplies nourishment to eye
pupil
light enter interior of eye through pupil
iris
changes size of pupil, depending on how much light should be let in; helps focus image with pupil size
lens
using visual accommodation it changes its shape from thick to thin, focusing on close/far objects
presbyopia
lose ability to change lens thickness because of age
myopia
shape of eye causes focal point to fall short of retina (nearsighted)
hyperopia
focus point behind retina (farsighted)
vitreous humor
nourishes eye and gives its shape
retina
light-sensitive area containing layers: ganglion cells, bipolar cells, rods and cones
cones
- center
- color
rods
- light, dark
- black, white, gray
- periphery
- brightness
- motion
blindspot/optic disk
axons of ganglion cells leave retina to become optic nerve; no rods/cones; if stare at one spot with one eye long enough objects that slowly cross visual field may disappear because “hole” in retina
temporal retinas
retina halves toward temples of head; axons project to visual cortex on same side of brain
nasal retinas
retina halves toward nose; axons project to visual cortex on opposite side of brain
left visual field
information goes to right visual cortex
right visual field
information goes to left visual cortex
dark adaptation
occurs as eye recovers its ability to see when going from brightly lit to dark; brighter lights take longer to adapt; rods allow eyes to adapt to low light (takes a while to completely adapt)
night blindness
person has difficulty seeing well enough to drive at night/get around in darkened area
light adaptation
cones adapt to increased level of light (adapts completely almost immediately)
trichromatic theory
Thomas Young
- red, blue, green
- mixing direct light results in lighter colors and creates white when mixing red, blue, green
- mixing reflected light results in darker colors
- different shades of colors correspond to different amounts of light received by the cones (rate at which combination of cones fire determines color that’s seen
red/green = yellow red/blue = magenta blue/green = cyan
Brown and Wald
- found that wavelengths correspond to color
short (420 nm) blue/violet
medium (530 nm) green
long (560 nm) green/yellow
afterimage
occurs when visible sensation persists for brief time even after OG stimulus is removed
opponent-process theory
Hering
- 4 primary colors {red, green} {blue, yellow}
- if one member of pair is strongly stimulated, other is inhibited can’t work
- this pairing causes afterimage b/c neurons are stimulated from specific part of visual spectrum and inhibited from somewhere else so area that stimulates becomes fatigued and then fatigued cell responds less than OG baseline
color blindness/color-deficient vision
caused by defective cones in retina
monochrome color blindness
people either have no cones or have cones that don’t work; everything is shades of gray
dichromatic vision
caused by one cone that doesn’t work properly so see everything in combos of 2 cones/colors
- red green color deficiency
- blue yellow color deficiency
red-green color deficiency
lack of functioning red or green cones; person confuses reds and greens; sees in blues, yellows, shades of gray
blue-yellow color deficiency
lack of functioning blue cones (rare); sees in reds, greens, grays
wavelength
pitch (how high/low sound is)
amplitude
volume
saturation/purity
timbre (richness)
pinna
visible, external part of ear that serves as concentrator, funneling sound waves from outside into ear; entrance to auditory canal/ear canal
auditory/ear canal
short tunnel that runs down to tympanic membrane/eardrum (when sound waves hit eardrum it causes 3 tiny bones in middle ear to vibrate)
ossicles
hammer (malleus)
anvil (incus)
stirrup (stapes)
- vibrations amplify vibrations from eardrum
oval window
membrane covering opening of inner ear; its vibrations set off chain reaction within inner ear
cochlea
filled with fluid; snail-shaped structure; when oval window vibrates, fluid in cochlea vibrates
basilar membrane
membrane running through middle of cochlea; when basilar membrane vibrates, the organ of Corti vibrates
organ of Corti
contains receptor cells for sense of hearing; is in basilar membrane; when organ of Corti vibrates it brushes against membrane above it
hair cells
located on organ of Corti; receptors for sound; when they’re bent up against other membrane they send neural message through auditory nerve into brain to auditory cortex, and cortex interprets sounds (louder sound –> stronger vibrations –> more hair cells stimulated)
auditory nerve
contains axons of all receptor neurons
place theory
pitch person hears depends on where hair cells that are stimulated are located on organ of Corti
- high pitched sounds –> hair cells located near oval window are stimulated
- low pitched sounds –> hair cells located far away on organ of Corti are stimulated
frequency theory
pitch is related to how fast basilar membrane vibrates (faster vibrations = higher pitch)
all auditory neurons fire at same time
correct pitch theory
frequency theory works for low pitches and place theory works for moderate/high pitches
volley principle
groups of auditory neurons take turns firing
conduction hearing impairment/loss
problems with mechanics of outer or middle ear and sound vibrations can’t be passed from eardrum to cochlea
nerve hearing impairment/sensorineural hearing loss
problem with inner ear or in auditory pathways and cortical areas of brain
tinnitus
ringing in one’s ear
cochlear implant
sends signals from microphone worn behind ear to sound processor which translates signals into electrical stimuli that are sent to electrodes implanted in cochlea, allowing transduction to occur and stimulate auditory nerve; brain processes electrode information as sound
taste buds/taste receptor cells
special neurons found in mouth that are responsible for taste
papillae
bumps on tongue; taste buds line walls of papillae
5 basic tastes
sweet sour salty bitter umami
olfaction/olfactory sense
ability to smell odors
olfactory receptor cells
each have cilia that project into cavity; receptor sites on cilia that send signals to brain when stimulated by molecules of substances in air around them
olfactory bulbs
located on top of sinus cavity beneath frontal lobes
somesthetic senses
skin senses
kinesthetic senses
vestibular senses
skin senses
has to do with touch, pressure, temperature, pain
kinesthetic senses
has to do with location of body parts in relation to each other
vestibular senses
has to do with movement and body position
pacinian corpuscles
receptors that respond to changes in pressure
nerve ending wrapped around ends of hair follicles
sensitive to pain and touch
free nerve endings
respond to changes in temperature, pressure, pain
visceral pain
receptors that detect pain and pressure in organs
primary somatic pain
pain sensations in skin, muscles, tendons, and joints are carried on large nerve fibers; pain is sharp and fast
secondary somatic pain
carried on small nerve fibers and pain is slower and more general ache
CIPA
disorder that makes people unable to feel pain; can’t cool off body by sweating; affect neural pathways that carry pain, heat, and cold sensations
congenital analgesia
disorder that makes people unable to feel pain; affect neural pathways that carry pain, heat, and cold sensations
phantom limb pain
occurs when person who has limb removed sometimes “feels” pain in missing limb
gate-control theory
pain signals pass through “gate” located in spinal cord; gate represents relative balance in neural activity of cells in spinal cord that receive information from body and them send information to brain
endorphins
body’s natural morphine; psychological aspects can influence its release; can inhibit transmission of pain signals and substance P
substance P
neuromodulator released from stimulation of pain receptor cells
proprioceptors
joint movement and muscles stretching/contracting
vestibular sense
balance
otolith organs
- tiny fluid sacs above cochlea with crystals
- head moves and crystals make fluid vibrate, setting off cilia on inner surface of sac, which tells person which direction they’re going
semicircular canals
- 3 tubes filled with fluid that stimulate cilia when rotated
- each tube is in a plane of motion
motion sickness
caused by disagreement between what eyes and body are saying
sensory conflict theory
normally vestibular sense coordinates with other senses but for some people the eyes conflict too much and it causes motion sickness
retinal disparity
each eye has own perspective on world (farther objects have similar image)
retinal convergence
eyes cross to focus on object coming closer
bottom-up processing
sensation first then perception
top-down processing
perception first then sensation
perceptual set
expectations prior knowledge situation age culture emotion
stroop color
name of color in a different color
cocktail party effect
ability to focus attention on specific stimulus while filtering out other stimuli
seize constancy
tendency to interpret objects as always being same size regardless of its distance from the viewer
shape constancy
tendency to interpret shape of object as constant, even when changes on retina
brightness constancy
tendency to perceive apparent brightness of object as same even when light conditions change
figure-grounds relationships
tendency to perceive objects/figures as existing on background
reversible figures
figure and ground switch back and forth
proximity/nearness
tendency to perceive objects that are close together as part of same grouping
similarity
tendency to perceive things that look alike as being part of same group
closure
tendency to complete figures that are incomplete
continuity
tendency to perceive things as simply as possible with a continuous pattern rather than with a complex broken up pattern
contiguity
tendency to perceive two things that happen close together in time as being related (seen as first event caused the second)
common region
tendency to perceive objects that are in same region as being in a group
depth perception
capability to see the world in 3-D
visual cliff
used table with big drop on one side to test if babies have depth perception –> they do
monocular cues
cues using one eye for perceiving depth in the world
binocular cues
cues using both eyes for perceiving depth in the world
linear perspective
tendency for parallel lines to seem to converge on each other
relative size
objects that people expect to be of certain size appear smaller and are assumed to be farther away
overlap/interposition
when 1 object seems to block another object, people assume that blocked object is behind first object and is farther away
aerial/atmospheric perspective
farther away object is, hazier it appears because particles of dust/dirt/pollutants in air
texture gradient
objects that are closer look very distinctly textured, and objects father away look blurry/not detailed
motion parallax
when in moving vehicle, objects close to vehicle seem to be moving very fast and objects far from vehicle seem to move very slowly
accommodation/muscular cue
tendency of lens to change shape/thickness in response to objects near of far away
Hubel and Wiesel
discovered simple cells (neurons), complex cells (orientation/movements), end-stopped cells (corners/curvatures/sudden edges)
hermann grid
matrix of squares where gray blobs are at intersections until you focus on intersection and they disappear
feature detectors
simple cells, complex cells, end-stopped cells
muller-lyer illusion
line are same length but with arrows pointing in different directions on the ends of the lines
horizontal-vertical illusion
vertical line is perceived to be larger than horizontal line
moon illusion
moon on horizontal appears to be much larger than moon in sky
apparent distance hypothesis
cues for depth allow people to know when objects are far away
autokinetic effect
small/stationary light in dark room appears to move because there’s no cues to indicate light isn’t moving
stroboscopic motion
rapid series of still pictures seem to be in motion
phi phenomenon
lights turned on in sequence appear to move
rotating snakes illusion
eye movements play significant role in perceiving the snakes rotating in circles
enigma painting
rings sparkle or rotate
