Sensation and Perception 5 Flashcards
perception
method by which brain takes all sensations person experiences at any given moment and allows them to be interpreted in some meaningful fashion
some individually to it
cocktail party effect
ability to focus attention on a specific stimulus while filtering out a myriad of other stimuli
hear what is important to you and filter out (innate) what perceive as less important stimulus
size constancy
form of perceptual constancy
tendency to interpret object as always being the same size, regardless of distance from viewer or size of image casts on retina
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
gestalt principles of perception
tendency to group objects and perceive whole shapes
following
prox, sim, clos, contin, contig, common region (later)
necker cube
problem = conflicting sets of depth cues, so viewer never sure which plane or edge in back and which in front
figure-ground relationships
tendency to perceive objects or figures as existing on a background
reversible figures
reversible figures
figure and ground seem to switch back and forth
proximity
tendency to perceive objects that are close to one another as part of same grouping
nearness
similarity
tendency to perceive things that look similar 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
first event seen as causing second
ventriloquy
common region
not one of original principles
palmer
tendency to perceive objects that are in a common area or region as being in a group
depth perception
capability to see world in three dimensions
present in infants at young age
cues for perceiving depth = monocular cues and binocular cues
visual cliff study
babies on table with pattern on half of top and bottom of other half, babies don’t want to go where pattern is on bottom, have some depth perception
gibson and walk
monocular cues
depth cue
use of only one eye
aka pictorial depth cues bc artists can use cues to give illusion of depth to paintings and drawings
linear perspective, relative size, overlap, aerial perspective, texture gradient, motion parallax, accommodation
binocular cues
depth cue
need both eye visual fields
convergene, binocular disparity
linear perspective
tendency for lines that are actually parallel to seem to converge on each other
people assume converging lines indicate ends of lines are great distance away from where people are
m
relative size
size constancy
objects that people expect to be of a certain size appear to be small and are, therefore, assumed to be much farther away
m
overlap
aka interposition
if one object seems to be blocking another object, people assume blocked object is behind first one and, therefore, farther away
m
aerial (atmospheric) perspective
farther away object is, hazier the object will appear to be due to tiny particles of dust, dirt, and other pollutants in the air
m
texture gradient
used by artists to give illusion of depth in painting
close things distinctly textured, but farther things = texture smaller and finer
m
motion parallax
discrepancy in motion of near and far objects
in car, trees go by quickly but mountain move slower
m
accommodation
monocular but not pictorial
muscular cue
brain uses info about visual accommodation (lens changes shape or thickness in response to objects near or far away) as a cue for distance
convergence
muscular cue
rotation of two eyes in sockets to focus on single object
object close = large convergence (almost crossing eyes)
object far = less convergence
b
binocular disparity
bc eyes few inches apart, don’t see exact same image
brain interprets images on retina to determine distance from the eyes
if two images diff, object close, if two images similar, object farther away
illusion
perception that doesn’t correspond to reality
distorted perception of something really there
sometimes based on early sensory processes, subsequent processing, or higher level assumptions made by visual system
color afterimages due to opponent processing in retina or lateral geniculate nucleus
hermann grid
black squares, white lines, see gray blobs where white lines converge
one ex = responses of neurons in primary visual cortex that respond best to bars of light of specific orientation (simple cells)
feature detectors
huber and wiesel
simple cells = respond best to bars of light of specific orientation
complex cells = respond to orientation and movement
end-stopped cells = respond best to corners, culture, or sudden edges
all three kinds collectively = feature detectors bc respond to specific features of stimulus
need straight edges for illusion to occur
muller lyer illusion
try to determine if two lines same length
identical but one line looks longer than other (one w angles on end facing out)
people pull inward facing angles toward them like outside corners of building, and make outward facing angles stretch away
western cultures more susceptible to illusion
zulu not susceptible bc few straight lines in culture
moon illusion
moon on horizon appears larger than moon in sky
ex = moon in sky alone, no depth cues, but on horizon, moon behind stuff, make horizon seem far away, moon farther away, magnify moon in mind (misapplication of size constancy
apparent distance hypothesis
bc people know object farther away from them yet still appear large are large, magnify moon in mind
autokinetic effect
small stationary light in dark room appear to move or drift bc no surrounding cues to indicate not moving
stroboscopic motion
in movies
rapid series of still pictures seem to be in motion
phi phenomenon
lights turned on in sequence appear to move
ex open signs, strings of light
rotating snakes illusion
kitaoka
increase in brain activity in visual area sensitive to motion, greatest when w accompanied by guided eye movements
enigma
levant
eye movements primary cause for illusory motion in enigma
microsaccades (tiny eye movements) directly linked to perception of motion
