Perception

Perception

process of understanding and interpreting sensations

psychophysics

study of interaction between sensation we receive and our experience of them

absolute threshold

minimum stimulus we can detect 50% of the time, individual variation is taken into account

sublimal

stimuli below our absolute threshold

just noticeable difference

smallest amount of change needed in a stimulus before we notice diff

webers law

change needed is proportional to intensity of stimulus, more intense=need more change before we notice

pheromones

chemical signals secreted by an organism that triggers a social response by other members of the same species

webers law volume

5%

perceptual theories

doesn’t compete with each other

perceptual theories examples

signal detection theory, top down processing, bottom up processing

signal detection theory

what will we perceive among competing stimuli

response criteria

how motivated we are to detect certain stimuli, what we expect to perceive

top down processing

perceive by filling in gaps for what we sense

schema

mental representations of how we expect the world to be

perceptual set

predisposition to perceive something in certain way

bottom up processing

longer, more accurate, use features to build compete perception

figure ground relationship

what part is image and what is background

Gestalt rules

we perceive images as groups, not isolated images

gestalt principle: proximity

close together is more likely to be perceived in group

gestalt principle: similarity

similar shapes are usually perceived in same group

gestalt principle: continuity

geometric figure more likely to be perceived in group

gestal principle: closure

recognizable images, top down processing

constancy

our able to maintain constant perception even with object changing in lighting

size constancy

we keep constant size in mind even when farther or nearer

shape constancy

familiarity with shape of object

brightness constancy

we see brick wall as red eve when grey and dark

perceived motion

detects how fast images move across our retina and take account our own movement then we perceive

stroboscopic effect

flip book, certain speed appears to move

phi phenomenon

light on and off at certain speed appears to stay on

auto kinetic effect

light projected onto one place appears to be moving if we stare

when does visual cliff develop

3 months

monocular depth cues

not depend on having two eyes, linear perspective, relative size, texture gradient

binocular depth cues

depends on having two eyes, retinal disparity and convergence

retinal disparity

brain receives info from both eyes and closer the object, more disparity between images coming form each

convergence

closer an object, more our eyes converge

does culture have effect on perception

yes, muller lyer illusion

extrasensory perception

claiming to have more than 5 senses and vestibular