Chapter 4: Sensation + Perception Flashcards
perception
definition
the brain’s interpretation of raw sensory inputs
explain how perception occurs within the brain
the energy from the raw sensory inputs is tranduced/encoded into neural signals + transmitted along neural axons to auditory centers in the temporal lobe of the forebrain
sensation
definition
detection of physical energy by sense organs (eyes, ears, skin, nose, tongue) which then send information to the brain
sensation
example
energy in the form of vibration/sound waves activates specialized auditory receptors in the ears
all conscious experiences drived from physical/chemical information flowing through our senses are ____
perceptions or sensations?
perceptions
when you tickle my back, I get a weird ____
perception or sensation?
perception
illusion
definition
when the way we percieve a stimulus doesn’t match its physical activity
____ first allows us to pick up the signals in our environments + ____ then allows us to assemble these signals into something meaningful
perception or sensation?
sensation, perception
naive realism
definition
the belief that we see the world precisely as it is
is naive realism correct?
no
-the world isn’t precisely as we see it
-we sample only a tiny portion of the world
transduction
definition
the process of converting an external energy/substance into electrical activity wtihin neurons
transduction
example
the neural messages are interpreted as meaningful sounds by the auditory cortex + auditory association areas of the temporal lobe
sense receptor
definition
specialized cell that transduces a specific stimulus
sensory adaptation
definition
for all of our senses, activation is greatest when we first detect a stimulus
for all of our senses, when is activation the greatest?
when we first detect a stimulus
sensory adaptation
example
the initial smell of perfume in a store is super strong, but as you walk around it becomes less strong
absolute threshold
definition
the minimum intensity of a stimulus necessary for it to be detected at least 50% of the time
is absolute threshold the same for every person?
no
-differs from person to person for each sense
-may also vary with psychological conditions
absolute threshold
example
the radio isn’t super loud but goes from none to being able to sense something a little bit
just noticeable difference (JND)
definition
the smallest difference between 2 stimuli that can be detected by an appropriate sense organ
just noticeable difference
example
-when listening to the radio in the car, if you turn the volume from 5 to 7, you can already hear the difference in sound
-however, if it’s between 30 and 32 you can’t sense the difference
-therefore, you sometimes need a bigger difference to detect the distinction between the 2 volumes
weber’s law
definition
-there is a constant proportional relationship between JND + the original stimulus intensity
-therefore, the stronger the stimulus, a bigger change is needed for a change in stimulus intensity to be noticeable
signal detection theory
definition
how we detect stimuli under uncertain conditions
signal-to-noise ratio
definition
it becomes harder to detect a signal as background noise increases
response bias
definition
the tendency to guess wrong/untruthfully when in doubt + under noisy conditions
what does the frequency of false-negatives + false-positives help us measure?
how biased participants are to respond “yes” or “no” in general
true positive
definition
respond yes, stimulus present
false negative
definition
respond no, stimulus present
false positive
definition
respond yes, stimulus absent
true negative
definition
respond no, stimulus absent
even though there are many distinct stimulus energies (light, sound, touch)…
the sensation we experience is determined by the nature of the ____
stimulus or sensory receptor?
sensory receptor
phosphenes
definition
vivid sensations of light caused by pressure on your eye’s receptor cells
where do phosphenes occur in our brain?
cerebral cortex
-doesn’t matter to our brain whether light or touch activated the sensory receptor, our brains react in the same way to either case
what do phosphenes look like?
sparks or similar to the multicolored shapes in a kaleidoscope
what can phosphenes potentially explain?
certain reports of ghosts + UFOs
synesthesia
definition
a remarkable condition in which people experience cross-modal process
synesthesia
example
hearing sounds when seeing colors
why does synesthesia occur?
2 reasons
-crosstalk among different brain regions
-a single brain region may serve double duty
crosstalk in synesthesia
example
-hear high tone with ligher colors + low tone with darker colors
-seeing a pat on someone’s shoulder + feeling the pat on your own shoulder
single brain region serving double duty in synesthesia
example
neurons in the auditory cortex tune to sound + also respond to touch
-if visual stimuli enhanced touch perception
mirror-touch synesthesia
definition
a person experiences the same sensation that another person experiences
-such as touch
lexical-gustatory synesthesia
definition
words are associated with specific tastes/textures
chromesthesia
definition
sounds trigger the experience of color
misophonia
definition
sounds trigger strong emotions such as anger/fear
personification
numbers, letters, or days of the week take on personality characteristics + sometimes have a characteristic appearance
personification
example
-6 might be experienced as a king
-8 might be experienced as a sorcerer
number-form synesthesia
definition
numbers are imagined as mental maps
spatial sequence synesthesia
definition
certain sequences of numbers, dates, or months are perceived as closer/farther in space
psychophysics
definition
the study of how we perceive sensory stimuli based on their physical characteristics
selective attention
definition
process of selecting 1 sensory channel + ignoring/minimizing others
cocktail party effect
definition
if you go to a party + it is loud, you are still able to continue your conversation
exception to cocktail party effect
if you are at a party talking in a group + hear your name being called by someone on the other side of the room, you can still detect that
cocktail party effect is under the category of ____
selective attention
filter theory of attention
definition
views attention as a bottleneck through which information passes
-our mental filter slows down information by enabling us to pay attention to important stimuli + ignore others
inattentional blindness
definition
failure to detect stimuli that are in plain sight when our attention is focused elsewhere
change blindness
definition
failure to detect obvious changes in one’s environment
binding problem
definition
when we percieve an apple, different regions of our brains process different aspects of it
-we don’t really know how our brains manage to combine these diverse pieces of information into a unified whole
light
definition
a form of electromagnetic energy with brightness influenced by the intesnity of the reflected light that reaches our eyes
hue
definition
the color of light
acuity
definition
sharpness of vision
pupil
definition
a circular hole through which light enters the eye
why does the pupil dilate?
to process complex information + attractive faces
cornea
definition
bends light waves to focus image on retina
lens
definition
bends light to fine-tune visual image
where is the lens located?
behind the cornea
lens accomondation
definition
flat or fat
flat lens accomodation
definition
-long, skinny
-lens for distant objects
fat lens accomodation
definition
-short, wide
-lens for nearby objects
retina
definition
has 2 types of receptor cells for seeing light + color
-rods
-cones
rods
definition
-for seeing basic shapes + forms
-long + narrow
-allows us to see in low levels of light
cones
definition
for color vision
dark adaptation
definition
time in the dark before rods regain maximum light sensitivity
photopigments
definition
chemicals that change following exposure to light
rhodopsin
definition
photopigment in rods
what vitamin improves vision + when?
vitamin A
-only improves vision when vision is impaired due to a vitamin A deficiency
fovea
definition
the central portion of the retina
optic nerve
definition
-contains the axons of ganglion cells
-travels from the retina to the rest of the brain
blind spot
definition
-a part of the visual field we can’t see
-a region of the retina containing no rods/sense receptors because axons of ganglion cells push everything else aside
what do blind spots contribute to?
our visual illusion
feature detection
definition
our ability to use certain minimal patterns to identify objects
feature detector cells
definition
detect lines + edges
-there are more complex feature detector cells at later levels of visual processing that detect lines of specific lengths, complex shapes, + moving objects
trichromatic theory
definition
we base our color vision on 3 primary colors with having 3 kinds of cones, each maximally sensitive to different wavelengths of light
what 3 colors do we base our vision on?- according to trichromatic theory
-blue
-green
-red
absence/reduced number of 1 or more types of cones due to genetic abnormalities leads to ____
color blindness
color blindness
definition
inability to see all/some colors
monochromat
definition
-people with 1 type of cone
-lose all color vision
-rare
dichromat
definition
-people with 2 types of cones
-missing only 1
-ex: red-green color blindness
trichromat
definition
having all 3 cones
tetrachromat
definition
4 types of cones
-blue, green, red, + additional cone for a color bewteen red + green
opponent process theory
definition
we perceive colors in terms of 3 pairs of opponent cells
-red or green
-blue or yellow
-black or white
afterimages
definition
-occur when we’ve stared at 1 color for a long time then look away
-we will often see a different colored replica of the same image
does trichromatic theory address afterimage?
no
what theory addresses afterimage?
oponent process theory
echolocation
definition
certain animals (bats, dolphins, + many whales) emit sounds + listen to echoes to determine their distance from a wall/barrier
blindness
definition
-the inability to see
-vision is less than/equal to 20/200
motion blindness
definition
a disorder where patients can’t seemlessly string still images processed by their brains into the perception of ongoing motion
visual agnosia
definition
a deficit in perceiving objects
visual agnosia
example
if someone can’t name something as cake, they would instead ask for the “white triangle shaped piece”
blindsight
definition
phenomenon where blind people still make correct guesses about the visual appearance of things around them
reasons why people can have blindsight
name 2
-echolocation
-they are sensitive to auditory information; this is why they have a stick
myopia
definition
nearsightedness/the inability to see close objects well coupled with an inability to see far objects well
why does myopia occur?
when images are focused in front of the rear of the eye due to our cornea being too steep or our eyes being too long
parallel processing
definition
phenomenon of attending many sense modalities simultaneously
parallel processing
example
when you sense weight, feel, etc. when holding an object
bottom-up processing
definition
from raw input to concept
-like a detective; come up with a decision based on little information
bottom-up processing
example
I smell something very good + I hear a popping sound in the oven- I decide the perception of mom’s cooking
top-down processing
definition
from expectation to raw
-we already have expectations/theories that we use to apply to raw evidence
top-down processing
example
someone texts me “idk” but since I already have this concept, I can use it for processing
perceptual constancy
definition
the process by which we perceive stimuli consistently across varied conditions
shape constancy
definition
our ability to perceive objects as the same shape no matter what position they are in
size constancy
definition
our ability to perceive objects as the same size no matter how far away they are from us
color constancy
definition
our ability to perceive color consistently across different levels of lighting
different/same parts of the brain process different aspects of visual perception
different
humans have an innate tendency to perceive meaningfullness out of…
inherently meaningless or fragmented sensory impressions
original laws of Gestalt perceptual grouping
name 6
-proximity
-similarity
-closure
-continuity
-symmetry
-figure-ground
Gestalt perceptual grouping
proximity
definition
objects physically close to each other tend to be perceived as unified wholes
Gestalt perceptual grouping
similarity
definition
all things being equal, we see similar objects as comprising a whole, much more so than dissimilar objects
Gestalt perceptual grouping
closure
definition
if there is a gap in the image of a familiar object, we will mentally fill in the missing portion to form a meaningful whole
Gestalt perceptual grouping
continuity
definition
any visual elements that suggest a continued line will be grouped together
Gestalt perceptual grouping
symmetry
definition
we perceive objects that are symmetrically arranged as wholes more often than those that aren’t
Gestalt perceptual grouping
figure-ground
definition
we make instantaneous decisions to focus attention on what we believe to be the central figure
-we largely ignore what we believe to be the background
subjective contours
definition
the phenomenon where our brains often provide missing information about outlines
bistable image
definition
an image that can be perceived in 2 ways
emergence
definition
a perceptual Gestalt that almost jumps out from the page + hits us all at once
-related to bistable image
phi phenomenon
definition
the illusory preception of movement produced by the successive flashing of images
-the flashing lights that seem to circle around a movie sign
-these lights are actually jumping from 1 spot to another, but appear continuous
-shows that our perceptions of what’s moving + what’s not is based only on partial information, with our brains taking their best guesses about what’s missing
depth perception
definition
the ability to see spatial relations in 3 dimensions
depth perception
example
enables us to reach for a glass + grasp it rather than knock it over + spill its contents
monocular cues
definition
perceiving 3 dimensions using only 1 eye with pictoral cues
monocular cues
name 7
-relative size
-texture gradients
-interposition
-linear perspective
-height in plane
-light + shadow
-motion parallax
relative size
definition
all things being equal, more distant objects look smaller than closer objects
texture gradients
definition
the texture of objects become less apparent as objects move farther away
interposition
definition
if 1 object that is closer blocks our view of another objects behind it + we know this, we know which object is closer + which is farther away
linear perspective
definition
the outlines of rooms/buildings converge as distance increases to a vanishing point
-in reality, lines in parallel never meet but they appear to do so at a great distance
height in plane
definition
in a scene, distant objects tend to appear higher + nearer objects tend to appear lower
light + shadow
definition
objects cast shadows that give us a sense of their 3D form
motion parallax
definition
the ability to judge the distance of moving objects from their speed
is motion parallax pictoral?
no
binocular cues
definition
view of 2 visual fields with both eyes
binocular disparity
definition
left + right eyes transmit quite different information for near objects but see distant objects similarly
binocular convergence
definition
when we look at nearby objects, we focus on them reflexively by using our eye muscles to turn our eyes inward
audition
definition
our sense of hearing
biaural cue
definition
localizes sound sources heard by both ears
monaural cue
definition
localizes sound sources heard by 1 ear
subliminal perception
definition
processing of sensory information that occurs below the level of conscious awareness
extrasensory perception (ESP)
definition
perception for events outside the known channels of sensation
precognition
definition
acquiring knowledge of future events before they occur through paranormal means
telepathy
definition
reading other people’s minds
clairvoyance
definition
detecting the presence of objects/people hidden from view
sound
definition
mechanical vibration
what does pitch correspond to?
the frequency of the sound wave
higher frequency = ____ pitch
higher
unit for pitch
hertz
place theory
definition
a specific place along the basilar membrane matches a tone with a specific pitch
place theory is for high/low pitched sound?
high (5,000-20,000 Hz)
-hair cells located at the base of the basilar membrane are most excited by high-pitched tones
frequency theory
definition
rate at which neurons fire the acction potential reproduces the pitch
frequency theory is for high/low pitched sound?
low (up to 100 Hz)
volley theory
definition
sets of neurons fire at their highest rate, slightly out of sync with each other, to reach overall rates up to 5,000 Hz
volley theory is for high/low pitched sound?
low (100-5,000 Hz)
amplitude
definition
corresponds to loudness
for amplitude,
loud noise = ____ amplitude
increased
unit for amplitude
decibels
timbre
definition
the quality + complexity of a sound
why do different musical instruments + human voices sound different?
because they differ in timbre
outer ear
definition
-consists of pinna + ear cannel
-funnels sound waves onto the eardrum
pinna
definition
the part of the ear that we see
-skin + cartilage flap
middle ear
definition
contains the ossicles
ossicles
definition
the 3 tiniest bones in the body (hammer, anvil, + stirrup)
-vibrate at the frequency of the sound wave, transmitting it from the eardrum to the inner ear
inner ear
definition
where the cochlea converts vibration into neural activity
-contains organ of Corti, basilar membrane, + semicircular canals
cochlea
definition
bony, spinal-shaped sense organ used for hearing
organ of Corti
definition
tissue containing the hair cells necesary for hearing
basilar membrane
definition
membrane supporting the organ of Corti + hair cells in the cochlea
auditory nerve
definition
sends information into the brain through the thalamus
thalamus
definition
sensory relay station
semicircular canals
definition
in the inner ear, responsible for balance
conductive deafness
definition
deafness due to malfunctioning of the ear
nerve deafness
definition
deafness due to damage to the auditory nerve
noise-induced hearing loss
definition
hearing loss due to damage to our hair cells from loud sounds
age-related hearing loss
definition
byproduct of the loss of sensory cells
-degeneration of the auditory nerve
olfaction
definition
smell
where are olfactory receptors located?
in the nasal passages
gustation
definition
taste
where are taste buds located?
in papillae
tongue taste map
definition
-a myth
-describes the tongue’s sensitivity to different flavors
when olfactor receptors come into contact with odor molecules (airborne chemicals), what happens?
action potentials in olfactory neurons are triggered
-smiilar for gustatory perception
pheromones
definition
odorless chemicals that serve as a social signal to members of one’s species
body senses
definition
touch, body position, + balance
somatosensory system
definition
senses touch, temperature, + pain
what does the somatosensory system sense with specialized nerve endings?
-light touch
-deep pressure
-temperature
what does the somatosensory system sense with free nerve endings?
-touch
-temperature
-ESPECIALLY pain
are nerve endings evenly distributed?
NO
-nerve endings are mostly in the fingertips
-followed by lips, face, hands, + feet
where are the fewest free nerve endings found?
middle back
describe how touch + pain information create perception
-first they activate local spinal reflexes
-then travel to brain sites dedicated to perception
gate control model
definition
idea that pain is blocked/gated from consciousness by neural mechanisms in the spinal cord
-accounts for how pain varies from situation to situation, depending on our psychological state
phantom pain
definition
pain or discomfort felt in an amputated limb
proprioception
definition
-sense of body position
-keeps track of where we are + helps to move efficiently
what is the “kinesthetic sense”?
proprioception
proprioceptors
definition
-stretch receptors in muscles
-force detectors in muscle tendons
describe how proprioceptive information creates perception
proprioceptive info ->
spinal cord ->
brain stem + thalamus ->
somatosensory + motor cortexes + intention ->
perception of location
vestibular sense
definition
sense of balance + equilibrium
-enables us to sense + maintain our balanace as we move about
what senses equilibrium + maintain balanace?
the 3 semicircular canals in the inner ear filled with fluid
describe how vestibular information travels to cause reflexes
vestibular info ->
brain stem ->
reflexes that coordinate eye/head movements
describe how vestibular information travels to create balance
vestibular info ->
cerebellum ->
catch balance when falling
