perception

selective attention

selective attention

you’re only consciously paying attention to a small portion of sensory stimuli

cocktail party effect

you are unconsciously processing all of the stimuli

hear everything but your brain is a filter

change blindness

you are unaware of even significant changes b/c your attention is a spotlight (focuses on one thing and ignores everything else)

gestalt

• there’s a pattern we unknowingly follow to make order out of chaos

1) figure ground

2) grouping

figure ground

pulls an image forward and its background back

proximity

groups things that are near each other

similarity

things that are similar get grouped together

continuity

things that overlap/are continuous are interrupted

connectedness

things that are touching are grouped together

closure

brain fills in missing gaps

depth perception

ability to see objects in 3 dimensions although the images that strike the retina are 2 dimensional; allows us to judge distance

binocular cues

depth cues, such as retinal disparity and convergence, that depend on the use of 2 eyes

retinal disparity

getting 2 slightly different messages on 2 slightly different retina to send depth info to brain

convergence

eye muscles turn in (converge) as smth gets closer, sending depth info to the brain

monocular depth cues

distance cues, such as linear perspective and overlap, available to either eye alone

-relative size, interposition, relative clarity, texture gradient, relative height, relative motion, linear perspective, light and shadow

relative size

if we assume that 2 objects are similar in size, we perceive the one that casts the smaller retinal image as farther away

interposition

if one object partially blocks our view of another, we perceive it as closer

relative clarity

hazy objects= far, while sharp and clear objects= close

texture gradient

coarse, distinct texture to a fine, indistinct texture = increasing distance

relative height

the higher the object, the farther we perceive it

relative motion/motion parallax

as we move, objects may appear to move

objects beyond our eyes’s fixation pnt appear to move w/you —> farther= lower apparent speed

linear perspective

parallel lines appear to converge with distance

increase convergence= increase distance

light and shadow

dimmer objects seem farther away b/c nearby objects reflect more light to our eyes

motion perception

stroboscopic movement and phi phenomenon

stroboscopic movement

brain interprets a rapid series of slightly varying images as continuous movement

phi phenomenon

an illusion of movement created when 2+ adjacent lights blink on and off in succession

shape constancy

we perceive the form of familiar objects as constant even while our retinal images of them change

e.g: shadow of a door becomes more trapezoidal as we open it, but we still perceive it as rectangular (like the door)

size constancy

objects size = constant, even while our distance from them varies

e.g: car 10 blocks away is still large

lightness constancy

we perceive an object as having a constant lightness, even when its illumination varies

e.g: white paper is still white in the dark

relative luminescence

amnt of light an object reflects relative to its surroundings

even though the retina is interpreting varying shapes/sizes of an object based on its shadows/reflections, we perceive familiar objects as constant

perceptual adaptation

in vision, the ability to adjust to an artificially displaced or even inverted visual field

e.g: getting used to new glasses

perceptual set

context influences perception

depends on the order in which info is presented to you

human factors psychology

explores how ppl and machines interact and how machines and physical environments can be adapted to human behaviors

Eleanor Gibson

discovered that depth perception is partially innate based on the visual cliff experiment results

visual cliff experiment

placing a glass covered table w/ a cliff edge, creating the illusion of a drop off, and observing whether subjects avoid stepping off the edge or not

showed that infants could perceive depth using visual clues even before they were able to crawl (around 6 months)