Sensation+perception Flashcards
sensation
the process by which our sensory receptions and nervous system get and show stimulus energies from our environment.
perception
organizing and interpreting sensory information, allowing us to recognize meaningful objects and events
top-down vs bottom-up processing
top-down: stimulus –> perception/interp of stim, bottom up: preconcieved notions shape interpretation of stimulus
absolute threshold
the lowest amount of stimulus needed to detect a particular stimulus 50% of the time
signal detection theory
predicts how and when we detect the presence of a faint stimulus (signal) against background stimulation (noise)
subliminal
below your absolute threshold for conscious awareness
difference threshold
the minimum difference between 2 stimuli required for detection 505 of the time- we experience this as the just noticeable difference
Weber’s law
the principle that says to be perceived as different, to stimuli must differ by a constant minimum percentage
sensory adaptation
brain no longer attends to a constant stimulus, even if you think about it you can’t sense it (you hair on your head, unless you move)
sensory habituation
brain gets used to the stimulus and ignores it, but can still perceive it if given conscious thought (you stop paying attention to a fan, but you can still hear whether it is on or off if asked)
sensory accommodation
body changes to adjust to stimulus- pupils dilate to accomodats more light
transduction
conversion of one form of energy to another
energy senses
perceive energy- sight (light), hearing (sound waves), touch (pressure)
chemical senses
detect chemicals- smell and taste
feature detectors
individual neurons—or groups of neurons—in the brain which detect certain types of stimuli, like movements, shape, and angles,
parallel processing
multiple specialized cells provide a complete image by combining sensations of color, shape, shading and movement
trichromatic theory
AKA Young-Helmholtz theory. retina contains red, blue and green cones, combining cones creates other colors. based on color theory (all=white, none=black)
opponent-processing theory
visual information comes in pairs (red-green, yellow-blue, white-black), explains afterimages
cornea
protective lens covering the eye, helps focus light reflection onto retina
iris
colored muscle in eye that adjusts light intake
pupil
small adjustable opening in the eye that determines how much light is let in
lens
focuses incoming light rays in the eye
retina
multilayered tissue on inner surface of the eye
fovea
point of central focus in the eye
optic nerve
carries information from the eye to the brain
blind spot
due to a lack of receptor cells in the eye
rods
enable black+white vision, peripheral vision, perceiving motion, low light
cones
enable color vision, fine details, work best in well-lit conditions
pinna
outer lobe of ear
auditory canal
channel in outer/middle ear that channels sound waves to the eardrum
tympanic membrane
aka eardrum, vibrates with received sound waves, jostles the hammer, anvil and stirrup (bones of the inner ear)
cochlea
filled with fluid, gets jostled by the hammer, anvil, and stirrup due to incoming sound waves
cilia
fine hair inside the cochlea on the basilar membrane that sway due to the movement of fluid as the cochlea vibrates with sound waves, sending nerve impulses through the auditory nerve
amplitude
the height of each wave
hearing: loudness- tall=loud, short=soft
sight: intensity/brightness- tall=bright, short=dull
wavelength
the distance of one peak of the wave to another
hearing: pitch- short=high, long=low
sight: hue- short=blue (cinderella’s mice), long=reddish
place theory
we hear different pitches because different sound waves trigger activity at different places along the cochlea’s basilar membrane- recognizing the location of the neural signal = recognizing pitch.
explains high pitched sounds
frequency theory
the brain reads pitch by monitoring the frequency of neural impulses traveling up the auditory nerve. rate of neural impulses=frequency.
explains low pitched sounds
Nerve deafness aka sensorineural hearing loss
hearing loss caused by damage to the cochlea’s receptor cells or the auditory nerves. cochlear implants can translate sounds into electrical signals to convey sound to the brain
conduction hearing loss
hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea, sound cannot get through to the inner ear
vestibular sense
the sense of the head’s (and thus the body’s) movement and positions- sense of balance. managed by the semicircular canals and the vestibular sacs containing fluid in the inner ear.
kinesthetic sense
sensing position+movement of individual body parts
gate-control theory
spinal cord acts as a “gate” that opens or closes to feel or stop pain. the gates are opened by the activity of pain signals traveling up the small nerve fibers and is closed by activity in larger fibers or by information coming from the brain. not all pain felt equal, because gates not always same status. body focuses on current/recent, sharp, and wide pain.
bipolar cells and ganglion cells
neurons that help transmit visual info to the brain.
light enters through receptor cells, activates bipolar cells, activates ganglion cells, info carried through optic nerve to brain
synesthesia
sensory interactions- tasting color or sounds
gestalt
tendency to integrate pieces of info into meaningful wholes
figure and ground
organization of visual field into objects that stand out from their surroundings
grouping principles
tendency to organize stimuli into coherent groups
- proximity, similarity, continuity, closure, connectedness
monocular cues
only need one eye to see (relative size, interposition, relative clarity, texture gradient, relation motion, linear perspective, relative height, relative brightness)
relative size
we perceive objects that cast a smaller retinal image to be farther away
interposition
closer objects block distant objects
relative clarity
hazy=distant object
texture gradient
fine textures signals an increasing distance (lack of detail=indistinct=far)
relative motion
objects closer to a fixation point move faster and in an opposing direction to those objects that are farther away
relative height
higher up on paper= farther
linear perspective
parallel lines appear to converge in the distance, more convergence=farther away
relative brightness
nearby objects reflect more light onto our eyes than more distant objects, dimmer object seems farther.
binocular cues
require two eyes to see (retinal disparity, convergence)
retinal disparity
images from your two eyes differ in perspective, the brain puts the two images together- works better for close up objects- allows 3D perception with 2D pictures
convergence
neuromuscular cues- muscles tell brain where pupils are pointed (straight ahead=farther, inward=closer), works better with close up objects
phi phenomenon
when lights flash at a certain speed they tend to present illusions of motion.
motion perception
objects traveling towards us grow in size, vise versa
perceptual constancy
perceiving objects as unchanging even as illumination and retinal image change- we assume environment has changed, not the object
(color, shape, size, lightness)
perceive familiar objects as having consistency in different contexts
context effects
expectations based on situations, visual cues, and music- influences perception
perceptual set
a mental predisposition to perceive one thing and not another. what you perceive is based on context from your life+earlier thoughts
