AP Psych Unit 1B (sensation)

sensation

process of attending to and taking in stimuli from the environment

perception

interpretation and organization of incoming stimuli

top down processing

brain already has an expectation of what it’s going to see, hear, smell, touch, or taste (uses context)

bottom up processing

no prior expectations

absolute threshold

minimum amount of a stimulus a person can detect 50% of the time

is there a positive or negative correlation between absolute threshold and a person’s ability to detec stimuli?

negative

difference threshold/just noticeable difference (JND)

smallest difference between two stimuli that a person can detect at least 50% of the time

weber’s law

states that stimuli have to differ by a constant proportion rather than amount (the greater the initial stimulus, the more you have to change it for the difference to be noticeable)

signal detection thory

explores likelihood of detecting a weak signal and provides 4 possible outcomes: hit, miss, false alarm, correct rejection

hit

person detects stimulus (correct)

miss

person does not detect stimulus (wrong)

false alarm

person reports stimulus when there was none (wrong)

correct rejection

person reports that there was no stimulus when there was none (correct)

sensory adaptation

receptors become less responsive in the presence of prolonged and continuous stimulation (if you try to pay attention to the stimulus again, you STILL WONT DETECT IT)

habituation

when person is no longer bothered by a stimulus or no longer notices it (brain stop paying attention to things that don’t change) if you try to pay attention to it again, YOU WILL DETECT IT AGAIN

subliminal messaging

the registration of stimuli below the level of awareness (brain receives info that’s below your absolute threshold so you don’t notice it but your brain does process it)

cornea

eye’s clear, protective outer layer of tissue covering the pupil and iris (light enters cornea first, and it helps focus light)

astigmatism

cornea is misshapen, so lights are not focused properly

pupil

opening in the center of iris through which light passes

iris

ring of muscle tissue that forms colored portion of eye (color affects light sensitivity, but not vision quality)

lens

transparent structure behind the pupil that changes shape to focus images on the retina

accomodation

the curvature of the lens of your eyes changes in response to changes in distance

retina

back wall of eye containing receptors (rods and cones) plus layers of neurons that begin the processing of visual info

transduction

sensory process that converts physical energy, like sound or light waves, into the form of neural messages

transduction process for vision

light waves are transduced into neural impulses by the rods and cones, then passed to bipolar cells and ganglion cells, and then the optic nerve

fovea centralis

central focal point of the retina, with the highest visual acuity due to highest concentration of cones

optic nerve

leaves through back of eye and carries the neural impulses from the eye to the brain

blind spot

head of optic nerve creates a blindspot because no receptor cells (rods or cones) are located there

rods

photoreceptors that detect BLACK, WHITE, and GRAY. Are necessary for PERIPHERAL VISION and twilight vision where cones don’t respond. There are many more rods than cones in the eye

cones

photoreceptors that are concentrated near the CENTER of the retina (fovea) and function in daylight or well lit conditions. specialized in COLOR VISION

trichromatic theory

states that there’s 3 types of cones (red, green, and blue) which combine to form 7.5 million hues

opponent process theory

humans are equipped with red/green cones and blue/yellow cells. when one in the pair is excited, the other is inhibited

color blindness

can see some colors, just can’t differentiate between some hues. more common in males because they are more likely to inherit the recessive gene since they have only one X chromosome

visual capture/McGurk effect

the tendency for vision to dominate other senses, causing a person to perceive and event based on what they see, even if other sensory input conflicts with it

Bipolar and ganglion cells

bipolar cells neurons in retina that receive signals from rods and cones and send them to ganglion cells which are neurons that summarize the info and send it to the brain via the optic nerve

dark adaptation

process by which rods become fully functional in the dark (takes 20 minutes)

afterimage

when you look at a picture for a certain period of time, you see and opposing colored image afterwards (opponent processing theory)

auditory canal

cone shaped part of inner ear that gathers sound waves from the environemnt and sends them toward the middle ear

eardrum/tympanic membrane

division between outer and middle ear (tightly stretched across auditory canal)—vibrates when sound comes in

ossicles

activated by eardrum vibration (comprised of hammer, anvil, and stirrup, the 3 smallest bones in the body)

hammer scientific name

malleus

anvil scientific name

incus

stirrup scientific name

stapes

order of tiny ear bones

Malleus (hammer), incus (anvil), stapes (stirrup)

oval window

stirrup (stapes) vibrates againt it which allows sound waves to enter the cochlea

cochlea

contains auditory receptors called cilia

basilar membrane

located on the interior of the fluid filled cochlea

cilia

like rods and cones of ear (fluid in cochlea transmits auditory vibrations to hair cells which transduce physical sound waves into electrical impulses, and the auditory nerve carries the messages to the brain)

where does auditory info go?

through thalamus into primary auditory cortex in temporal lobe

place theory

suggests that we identify the pitch of sounds according to the location of the vibrations on basilar membrane

if you unroll the cochlea, where is each type of receptor located?

high pitches on the left and low pitches on the right

frequency theory

brain identifies the pitch of sounds according to how rapidly the nerve impulses fire (cells fire at same frequency as sound wave) WORKS TOGETHER WITH VALLEY PRINCIPLE

valley principle

at very high frequencies, neurons fire in teams (they cannot fire as fast as the sound wave)

hertz

impulses per second

conduction deafness

associated with problems in carrying sound waves from middle to inner ear (could be due to problems with the ossicles or eardrums). common as a person ages

sensorineural (nerve) deafness

caused by damage to the hair cells in the basilar membrane of the auditory nerve (receptors don’t fire at max capacity). most common in people who are born deaf

sound localization

ability to determine the origin of a sound in terms of distance and direction

harder when sound is behind us because pinna is facin forward so sound is not directed as well

pinna

outer part of ear, directs sound waves

cochlear implants

help people with sensorineural deafness if the HAIR CELLS are damaged (NOT if auditory nerve is damaged)

sound wave properties

loudness/volume is determined by amplitude, pitch is determined by frequency. volume is in decibels, pitch in hertz

olfaction

smell (DOES NOT GO THROUGH THALAMUS)

olfactory cells

located in olfactory bulb of nasal cavity (cilia)

olfactory bulb

sends neural messages to brain

olfactory cortex

in temporal lobes, wired closely to the amygdala and hippocampus (thats why smells can trigger memories!)

anosmia

loss of smell

gustation

taste

papillae

small bumps on tounge surface that have taste buds (sensitivity declines with age)

taste buds

specialized cells that detect bitter, sour, sweet, salty, and umami tasted (5 different types of taste buds)

what type of taste buds decline most as we age?

bitter and sour

supertasters

the 25% of people born with especially high numbers of taste buds

non-tasters

fewer taste buds than normal

synesthesia

interaction of different senses (ex. hearing colors)

by age 20, what percentage of taste buds have we lost?

50%

sensory interaction

when senses influence each other (ex. flavor is a combo of smell and taste)

sense of touch

consists of 4 types of receptors that respond to pain, warmth, cold, and pressure

homunculus

figure depicting how much surface area each body part takes up on somatosensory cortex

somatosensory cortex

located in parietal lobe, processes incoming sensory messages

gate control theory of pain

states that there is a sort of neurological gate inthe spinal chord that opens to allow pain messages into the brain and closes to stop the signal (suggests that smaller nerve fibers carry pain, while large fibers carry other senses so stimulating the large fibers will distract from the pain carried by small fibers)

phantom limb syndrome

7/10 people experience a phenomenon where they feel pain or sensation in a limb they no longer have. happens because corresponding part in the somatosensory cortex is still intact

kinesthetic sense

helps move body parts in a very precise manner (relies on proprioceptors)

proprioceptors

specialized neurons found in joints, tendons, and muscles that give info about the position and movement of individual body parts

vestibular sense

sense of balance and whole body positioning (communicates with cerebellum)

semicircular canals

fluid filled tubes located near cochlea in inner ear, associate with balance (when fluid moves, you feel off balance)