selective attention
focusing of conscious awareness on a particular stimulus, as in cocktail party effect
inattentional blindness
failing to see visible objects when our attention is directed elsewhere
change blindness
after being distracted and refocusing on a particular stimulus, change in stimulus during distraction period goes undetected
change deafness
when focused on repeating a list, change in individual speaking goes unnoticed
pop-out
when distinct stimulus pops out and draws our attention
visual capture
tendancy for vision to dominate other senses
gestalt
an organized whole; tendancy to integrate pieces of information into meaningful wholes
figure-ground
organization of visual field into objects (figures) that stand out from surroundings (ground)
Grouping
perceptual tendancy to organize stimuli into coherant groups; has 5 rules
proximity
a rule for grouping; tendancy to group nearby objects figures together
similarity
rule for grouping; tendancy to group figures together that are similar
continuity
rule for grouping; tendancy to perceive smooth, continuous patterns
connectedness
rule for grouping; tendancy to perceive connected, similar figures as 1 unit
closure
rule for grouping; tendancy to fill in gaps to create complete whole objects
depth perception
the ability to see objects in 3D although the images that strike our retina are 2D; allows us to judge distance
visual cliff
labratory device for testing depth perception in infants and young animals
binocular cues
depth cues such as retinal disparity and convergence that depend on use of two eyes
retinal disparity
a binocular cue for perceiving depth; by comparing images from each eye, the brain computes distance; the greater the difference between two images the closer the object
convergence
binocular cue for perceiving depth; the estent to which the eyse converge inward when looking at an object; the greater the inward strain, the closer the object
monocular cues
depth cues such as interposition, relative size, and linear perspective available to each eye alone
relative size
a monocular cue; if we assume two objects are similar in size we perceive the one that casts the smaller retinal image as farther away
interposition
a monocular cue; if one object partially blocks the view of another, we perceive it as closer
relative clarity
a monocular cue; light from distant objects passes through more atmosphere therefore they are perceived as hazy and farther away than sharp, clear objects
texture gradient
a monocular cue; a gradual change from course, distinct texture to fine, indistinct textures signals increasing distance
relative height
a monocular cue; objects higher in our field of vision are perceived as farther away; causes the illusion that taller objects are longer than shorter objects
relative motion
a monocular cue; as we move, objects that are stationary appear to move; the closer the object, the faster it appears to move
Linear perspective
a monocular cue; parallel lines such as RR tracks, seem to converge with distance; the greater the convergence, the greater the distance perceived
light and shadow
a monocular cue; nearby objects reflect more light to our eyes, dimmer objects seem farther away (assuming light comes from above)
stroboscopic movement
brain perceives continuous movement in rapid series of slightly varying images
phi phenomenon
an illusion of movement created when two or more adjcent lights blink on and off in quick succession
motion perception of objects
shrinking objects are perceived to be retreating, enlarging objects appear to be approaching; large objects appear to move slower than small objects
perceptual constancy
perceiving objects as unchanging (in lightness, color, shape, size) as illumination and retinal images change; relating to top-down processing)
shape constancy
perceived shape can appear as staying consistant when angle is changes
size constancy
perceive objects as having constant size even as distance changes
lightness constancy
objects are perceived as having constant lightness despite illumination variations
relative luminance
amount of light an object reflects relative to surroundings
perceptual set
a mental predisposition to perceive one thing and not another; determined by our schemas and experiences
moon illusion
when the moon is closer to the horizon it looks 50 percent larger
Muller-Lyer illusion
distance determines length; lines farther away appear to be bigger than lines close to us
perceptual adaptation
in vision, the ability to adjust an artificially displaced or even inverted visual field
Human factors psychologists
psychologists who explore how people and machines interact, and how machines and physical environments can be made safe and easy to use; help design appliances, work settings to fit natural perceptions
extrasensory perception (ESP)
controvercial claim that perception can occur apart from sensory input; said to include telepathy, clairvoyance and precognition
telepathy
a type of ESP involving mind to mind communication
clairvoyance
a type of ESP involving perceiving remote events, for example sensing that your friends house is burning down
precognition
a type of ESP involving perceiving future events
psychokinesis
related to ESP; mind over matter principle; for example levitating a table, influencing a roll of dice
problems with ESP
rejects our understanding that we are creatures whose minds are tied to our physical brains, and our belief that perceptual experiences of the world are built on sensations
claims of ESP
astrological predictions, psychic healing, communication with dead, out of body experiences