Sensation/Perception Flashcards
Place Theory
auditory
the closer to the oval window in the ear (base) the higher the frequency (pitch)
the closer to the apex the lower the frequency
Weber’s Law
the just noticeable difference -> smallest difference you can detect 50% of the time
ex: think of comparison of 2 different weights
delta I/I = K
absolute threshold
lowest intensity value a person can detect a stimulus 50% of the time
experimentally found by seeing percentage of time a person accurately detects the stimulus
ex: Sam could hear a fly from across the room, so she has a higher absolute threshold than quinn who is practically deaf
also think of the hearing tests in kindergarten
Sensory Adaptation
adapting to the sensations around you to the point that you don’t notice them anymore
ex: not feeling your watch after a few minutes of wearing it; not being able to detect a weird smell after being there for a while
Mechanoreceptors
detect movement
stimuli: sound waves and touch
ex: hair cells in the ear
chemoreceptors
detect chemicals
stimuli: molecules, solutes
ex: taste buds
Thermoreceptor
detects temperature
stimuli: heat, cold
ex: skin
Photoreceptors
light waves
stimuli: visible light
ex: rods, cones (retina)
Signal Detection Theory
the more stimuli distractions (visual, cognitive, auditory) you add, the lower a person’s correct results to stimuli
external noise: auditory distraction
internal noise: cognitive processing
ex: when I’m studying for MCAT and watson is yelling outside, I become distracted and don’t do as well on thinking through the exam. When you add Kenzie talking and the tv playing, it becomes harder to focus with the extra distractions and the more I get incorrect on my exam.
PET scans
Positron Emission Tomography
uses radioactively labeled glucose to measure brain activity
produces 3D image of the brain showing hypermetabolic and hypometabolic regions
fMRI scans
look at oxygenation levels of the brain
the more oxygen to a specific area means more brain activity
scanner detects the differential properties of oxyhemoglobin and deoxyhemoglobin
feature detection
process by which nervous system sorts through/filters natural stimuli to only pick up on the most relevant stimuli and ignore the others
want to pick up behaviorally relevant cues
feature detector neurons only fire for specific movement, shapes, colors, angles etc
parallel processing
taking in multiple components and applying it to visualize an object
ex: seeing an object containing both movement and color
top-down processing
taking information we already know and applying it to a more generalized situation
ex: when seeing a picture with amino acids, you will automatically think you see all of them even if they aren’t all present because your brain already has that information
bottom-up processing
using sensory information to guide our perception; usually applied to novel experiences
ex: blind taste test
EEG
electroencephalogram
electrodes placed on scalp and connected to an amplifier
measures voltage fluctuations in the brain over time
cannot localize activity to a specific brain area
used to visually see seizures
CT
computerized tomography
computer combines multiple x-rays taken at different angles
measures detailed structure of internal organs and tissues at a single point in time
motion parallax
relative motion
monocular cue (one eye)
objects closer to the observer appear to be moving faster than the background
can perceive depth and motion
retinal disparity
each eye transmits a slightly different picture to the brain
helps infer distance
convergence
the amount the eye turns inward to focus on an object
the closer the object, the more convergence
helps infer distance
phi phenomenon
motion picture effect
optical illusion were still photos are flipped in rapid succession so it appears to be moving
taste aversion
a specific and powerful classical conditioning that occurs when an organism becomes ill after consuming something
only requires one pairing and has a long duration
most likely the organism will never eat the thing again
Gestalt principles
describes how human’s holistically perceive sensory stimuli
similarity
gestalt’s principle
tendency to group together objects that share similar features
- shape, color
common fate
perception that things moving together are grouped together
ex: flock of birds flying in V-formation is perceived as a unit
proximity
gestalt’s principle
perceive things that are physically closer to one another as a group
continuity
gestalt’s principle
tendency to perceive elements as continuing on a smooth path
closure
gestalt’s principle
tendency to see lines that are close together as closed and forming part of a picture
perceptual constancy
perception that an object’s characteristics remain stable even when the object seems to change because the environment was altered
applies to shape, color, brightness, and size
subjective contours
gestalt’s principle
illusions
our mind will fill in gaps to create images based on top-down processing
invariance
gestalt’s principle
objects can be recognized despite slight alterations
can be recognized in different spatial orientations or when it is depicted with dotted rather than solid lines
kinesthetic sense
proprioceptors in muscles, joints, tendons, and skin detect movement and position of body/limbs
kinesthetic input provides awareness of location of parts of the body in space and how they are moving
vestibular sense
maintains balance and orientation
motion sickness arises from conflict between vestibular system and visual input
organs within the inner ear
Otolithic organs
vestibular sense
located within the cochlea of the inner ear
contains utricle and saccule
detect gravity/acceleration
has crystals that attach to hair cells that are pulled when change head position, causing AP to fire
semicircular canals
vestibular sense
senses head rotation
contains anterior, posterior, and lateral semi-circular canals
maintenance of spatial orientation and balance relies on
visual input (provides input on orientation of body)
vestibular input (provides info on motion, equilibrium, and spatial orientation)
somatosensory input (proprioceptors, provide info on location and movement of body in space)
cochlea
located within inner ear
sound processing and transmission of auditory information to the temporal lobe of the brain
Monocular cues
depth cues that can be perceived using one eye only and often rely on comparisons between objects
include: interposition light and shadow texture gradient relative size relative height linear perspective
interposition
type of monocular cue
closer objects will overlap in front of object that are further away
create a sense of depth
light and shadow
monocular cue
highlights and shadows help to give objects the appearance of depth
texture gradient
monocular cue
closer objects are more fine detailed than objects that are further away
relative size
monocular cue
further objects appear smaller than closer objects of the same size
relative height
monocular cue
further objects are perceived at being higher in our line of sight
linear perspective
monocular cue
distances between parallel lines appear narrower as they become further away
stereopsis
perception of depth that arises from having retinas in 2 different locations that create one picture for your brain to process
binocular
convergence
the closer the object is to the observer, the more the eye turns inward to focus on the object
that angle indicated distance from the observer
sensory accommodation - eye
ciliary muscles of the eye alter the shape of the lens
this helps with depth perception - monocular cue
circadian rhythms
cycles in physiological activity that occur over 24 hour interval
align with synthesis and secretion of melatonin from pineal gland -> light dependent process
Ruffinian Endings
respond to pressure on the skin
What influences Absolute Threshold?
expectation
experience (how familiar you are with sound)
motivation
alertness
subliminal stimuli
stimuli below the absolute threshold
signal detection
how we make decisions under conditions of uncertainty - discern between actual presence or absence of stimuli
Hit = present and said yes
miss = present and said no
false alarm = not present and said yes
correct rejection = not present and said no
conservation strategy - signal detection
always say no unless 100% positive signal is present
will risk getting misses
liberal strategy - signal detection
always say yes
risk getting false alarms
Pragnanz
Gestalt’s principle
reality is often organized and reduced to simplest form possible
ex: olympic rings are 5 circles instead of lots of little shapes
conjunctiva
first layer light hits in the eye
cornea
transparent thick sheet of tissue in eye
anterior chamber - eye
space filled with aqueous humor, provides pressure to maintain shape of eyeball
located between cornea and pupil
pupil
hole that manipulates the amount of light that can enter the retina
lens
bends light so it goes to back of eyeball
suspensory ligaments
attached to ciliary muscle
secretes aqueous humor
also shapes eye to help see when objects change position in distance
posterior chamber
area behind ciliary muscle also filled with aqueous humor
vitreous chamber
filled with vitreous humor, jelly-like substance to provide pressure to eyeballs
retina
filled with photoreceptors
macula
special part of retina rich in cones
fovea
completely covered in cones, no rods
choroid
pigmented black in humans, network of blood vessels
sclera
whites of the eye, thick fibrous tissue that covers posterior of eyeball
attachment points for muscles
What is light
electromagnetic waves part of a large spectrum violet light = 400 nm red light = 700 nm
how does light enter eye
enters pupil and goes to retina which contains rods and cones
rods become turned off when light hits
when rod off, turns on bipolar cell which turns on a retinal ganglion cells which goes to optic nerve and enters brain
Phototransduction cascade
light hits rods and cones in retina
retina converts light into neural impulse
rods contain discs with proteins called rhodopsin
- rhodopsin contains molecule retinal which causes change from bent to straight
- once retinal changes shape, rhodopsin changes shape which causes transducin to break from rhodopsin and send its alpha particle to Phosphodiesterase
-Phosphodiesterase breaks down cGMP –> GMP which shuts off Na+ channels (because sodium channels are activated by cGMP)
- the cell becomes hyperpolarized and shuts off
when the rod shuts off - the bipolar cell is turned on which activates the retinal ganglion cell which sends information through axons to the optic nerve which tells the brain there is light entering the eye
transducin
made of 3 parts - alpha, beta, and gamma
breaks from rhodopsin when changes shape due to light
alpha becomes disk and binds to PDE
PDE takes cGMP and converts to GMP
Na+ channel which requires cGMP becomes closed
rods hyperpolarize and shut off
no longer inhbits ON bipolar cells
active bipolar cells activate retinal ganglion cells to send neural impulse to optic nerve and then to brain
Photoreceptors
takes light and converts to neural impulse
rods
low light - really sensitive to light
contain optic discs which proteins that fire AP -> become turned off when light present (bc of rhodopsin change of shape)
Black and white vision
slow recovery time - takes a while to adjust in the dark
mostly found in periphery
cones
specialized nerves that show color and clear images in full light
concentrated in the fovea
fat recovery time
blind spot
no cones or rods
the optic disc is the blind spot
parallel processing
seeing all at the same time and simultaneously process incoming stimuli that differs in quality
see both shape and color and motion to process that a basketball is coming toward you
sound waves
pressurized
think of putting hands together and having bunch of air molecules all wanting to escape
how close peaks are = frequency
different amplitudes = different loudness
How is sound processed?
sound enters outer ear through pinna –> external auditory meatus –> tympanic membrane (eardrum)
pressurized waves cause malleus, incus, and stapes to vibrate
stapes
part of the inner eardrum that is attached to the oval window
as it is pushed, fluid is condensed and enters cochlea where it moves to the round window and pushes it out
continues pushing fluid until sound wave is dissipated
Why doesn’t fluid that enters cochlea through oval window to the round window go back to oval window?
organ of Corti is a membrane that doesn’t allow fluid ot move backwards
organ of Corti includes basilar membrane and tectorial membrane
Basilar tuning
hair cells as base of cochlea activated by high frequency
near apex with low frequency sounds
primary auditory cortex
receives all information from the cochlea
sensitive to various frequencies in different locations
proprioception
sense of balance/position
cognitive awareness of body in space
kinaesthesia
movement of our body
behavioral
a-beta fibers
fast
thick and covered in myelin
less resistance, high conductance
a-delta fibers
smaller diameter, less myelin
c fibers
small diameter, unmyelinated (lingering sense of pain)
olfactory bulb
bundle of nerves that sends little projections through cribriform plate into olfactory epithelium
pheremones
chemical signal released by one member of the species and sense by another species to trigger an innate response
linked to mating, fighting, and communication
sweet, umami, and bitter cells rely on what type of receptor
GPCR
sour and salty cells rely on what type of receptor
ion channels
sour (hydrogen ion channels)
salty (sodium channels)
psychophysics
physiological study of relationship between physical stimuli and mental response
how much stimuli can we detect and how we detect differences between stimuli in the environment with out sensory systems
ex: can I hear the sound being played, and then can I detect a difference when a different pitch is played
goes in line with absolute threshold -> what can you accurately hear or taste or see
baroreceptor
receptors for pressure
nociceptor
receptor for pain
mechanoreceptor
receptor for touch and sound
Meissner’s corpuscle
sensitive to light touch
located in dermis
Pacinian corpuscle
sensitive to vibration and pressure
located in dermis
Merkel’s disk
sensitive to light touch
located in epidermis
Ruffini corpuscle
sensitive to stretching
located in dermis
layers of the skin
epidermis
dermis
pathway of light
cornea (focuses light) –> iris –> choroid & ciliary body (produces aqueous humor) –> lens (controls refraction of incoming light) –> ciliary muscle pulls on suspensory ligaments and changes shape of lens (accomodation) –> retina
muscles of iris
dilator pupillae –> opens pupil under sympathetic stimulation
constrictor pupillae –> constricts pupil under parasympathetic stimulation
basilar membrane
small organ within the cochlea that contains hair cells and serves as auditory system’s sensory receptors
cochlea
converts sound waves into electrical impulses
passage of sound through the inner ear
sound moves through the auditory canal to the tympanic membrane to the malleus, incus, and then stapes (ossicles). Goes to the round/oval window –> fluid inside cochlea begins to move –> fluid stimulates hair cells which stimulate generation of neural impulses that travel through auditory nerve to the brain
somatosensation
process that conveys information from body’s surface to the nervous system.
includes pain, pressure, temperature, proprioception, position, and muscle contraction
5 tastes
sweet, salty, bitter, sour, and umami
What sense is most closely tied to memory?
olfactory
kinesthesia
perception of the position of the body
kinesthetic learner wants to touch things. So kinesthesia is focusing on positioning
Ex: I use kinesthesia when I am walking or running because I need to know that my legs are underneath me
muscle spindle
receptors found in muscles that detect changes in the length of the muscle
golgi tendon organ
sensory receptor organ that can sense change in muscle tension. Found between tendons and muscles
optic disc
region of the retina where the optic nerve exits and the artery that supplies blood to the retina enters
known as the blind spot because has no photoreceptors
parvo pathway
travels from retina to ventral (lower) layers of the LGN –> ventral brain regions
the “what” pathway
perception of finer detail
form and color
magno pathway
travels from retina to dorsal (upper) layer of the LGN –> dorsal brain regions
the “where” pathway
perception of courser detail
depth and motion
stereocilia
component of hair cells that play role in auditory system
magnocellular cells
component of visual system, detect motion
distal stimuli
located outside the body
ex: you see a campfire, but seeing this campfire far away won’t affect you
proximal stimuli
directly interacts and affects the sensory receptors, informs the observer about the presence of distal stimuli
ex: that campfire won’t directly impact you, but the photons from the light will enter your retina and reach the cones and rods, and the observer will feel the heat from the combustion of the fire
psychophysicial discrimination testing
participant is presented with stimulus that are faried slightly and asked to identify if there is a difference. The original is increased until the participant notices a change
partial report
When the participant is asked to only report on particular information - they tend to remember that information way better than if they were to report on all the information
operational span testing
test to see the general capacity of working memory tasks, patients are asked to read and verify a simple math problem (is 4/2 -1 = 1?) then read a word after such as SNOW, after doing a series of problems and words they are asked to recall the word that followed each operation.
Predicts verbal abilities and reading comprehension even though the subject is solving a math problem. Argues that it implies a general pool of resources that is used in every type of working memory situation
word association testing
when given a word, you say the first word that pops into your head
Freud thought this told something about your personality
