perception Flashcards
sensation
physical stimulation of the five senses detected by sense receptors
perception
brain interpreting and organising sensory info
difference between sensation and perception
sensation is detection of stimulus
perception is interpretation of what stimulus means
ponzo illusion
misinterpreted depth cue
perceived horizontal line in longer than bottom line
muller lyer illusion
misinterpreted depth cue
two vertical lines same length
line with outgoing fins seen longer
rubin’s vase
ambiguous figure
face and vase
ames room
misinterpreted depth cue
trapezoid room
people seen as different sizes
binocular depth cues
need both eyes to judge distance size depth etc.
retinal disparity
eyes six cm apart so diff view of world
retina receives visual info
different between info gives info on distance
closer object more disparity
convergence
object coming towards us causes eyes to come together
muscles work harder when eyes come together
muscle info tells ur distance and depth
monocular depth cues
need only on eye to judge distance depth size etc.
height in plane
objects higher up in the visual field = further away
relative size
objects appear smaller in the visual field than known objects of similar size so they are perceived as further away
occlusion obscured objects look further away
linear perspective
parallel lines appear closer together and come to a point in distance
size constancy
objects perceived as constant size despite size on retina changing with distance
misinterpreted depth cue
brain perceives distance
objects in the distance are scaled up to look normal
ponzo illusion explanation
converging lines appear illusion of distance
mentally enlarges top line.
muller lyer explanation
ingoing fins appear as shape of outside building do scaled down
outgoing fins appear as outside of building so scaled up
ambiguous figures
two possible interpretations
brain can’t decide which one is correct
necker cube explanation
cube upwards to the right or downwards to left
fiction
seeing something that isn’t there
kanizsa triangle explanation
illusory contours create image of second triangle
gregory’s constructivist theory
make sense of the world by building our perceptions based on info we know and past cues
inference
what we perceive is ambiguous and incomplete
brain fill in gaps in our sensory info using inference / interpretation
visual cues (gregory’s theory)
brain has help when making interpretations using visual cues
sometimes what we interpret can turn out wrong
role of nurture in gregory’s theory
understanding of visual cues learnt from experience
perception more sophisticated as we grow up
strength of gregory’s theory
support from studies that show cultural differences in perception
different experiences have affected perception
nurture plays key role
weakness of gregory’s theory
supported by visual illusions which are unusual examples of perception
idea of mistake hypotheses has been useful to explain visual illusions
but these are artificial 2D images designed to fool us
doesn’t explain daily perception
weakness of gregory’s theory
cannot explain how perception works in first place
babies have perceptual abilities
not all perception is role of nurture
struggles to explain innate perception
gibson direct theory
perception doesn’t draw on past experiences
sufficient info for perception
sensation and perception are same
eyes detect everything we need without making inferences
optic flow partterns
when moving, things in distance appear stationary and everything else rushes past
perceptual info about speed and distance
motion parallax
monocular depth cue
when moving past them closer objects appear to move faster than objects that are further away
info about speed and distance
influence of nature
perception is innate not learnt
strength of gibsons theory
developed using research with pilots
his work meant his theory was good at explaining how everyday perception of things like movement and depth occur
real world relevance
weakness of gibson theory
difficult to explain perceptual errors
apparently all we need to perceive is the rich info at retina
our brain makes perceptual errors and draws wrong conclusion
gregory’s theory is better at explaining illusions
strength of gibsons theory
research with young infants provided support
gibson and walk 1960 showed infants were reluctant to go over the visual cliff
unlikely that their reluctance was from something they learnt as they were very young
some parts of human perception is innate supporting his theory
culture affecting perception
different cultures use depth cues differently so have diff perceptual set
emotion affecting perception
emotion affects perceptual set eg perceptual defence where our brain blocks out upsetting or embarrassing things
gilchrist and nesbergs aim
find out if food deprivation affects perception of food
if motivation is a factor that’s affects perception
gilchrist and nesbergs method
participants either deprived of food for 20 hours or not as a control group
shown 4 slides of meal
15 mins each
the same switched off and on again and asked to adjust lighting
gilchrist and nesbergs results
food deprived people perceived food as brighter the longer the deprived of food
gilchrist and nesbergs conclusion
sensitivity greater when food deprived
hunger motivating factor of perception of food
participants saw food as brighter and more appealing
strength of gilchrist and nesbergs study
support from other studies
sanford deprived participants of food for varying lengths of time
showed ambiguous figures
more food deprived more likely to perceive pictures as food
increased validity
weakness of gilchrist and nesbergs study
unethical to deprive people of food
although with consent participants may have not understood how hard it was and felt uncomfortable to withdraw as it would spoil the study
unfair for participants to go hungry for an experiment
weakness of gilchrist and nesbergs study
aspects of study were not like everyday life
asked to judge pictures of food rather than real food
judging pictures for brightness is not something we do daily
decreases generalisability
bruner and minturns study’s aim
if interpretation of an ambiguous figure was affected by context it was shown
bruner and minturns method
ambiguous figure either B or 13
independent groups design
either shown sequence of letters or numbers
participants report and draw what they saw
bruner and minturns results
more likely to see ambiguous figure as letter if corresponding sequence was letters vice versa
bruner and minturns conclusion
expectation is an important influence of perceptual set
changing context in which visual information presented can change the way it’s perceived
weakness of bruner and minturns study
ambiguous figure was used to test expectation which isn’t something we come across in daily life
designed to trick participants
on some occasions we may come across these kind of situations eg misreading spelling mistake but rare
weakness of bruner and minturns study
independent groups design used
individual differences between groups design eg more peoples name started with B in one group than other
participants variables may have affected so it’s weak
strength of bruner and minturns study
can explain errors people make in real world
US navy cruiser shot down civilian plane thinking it was military
he was in a military area therefore raised expectations that it was military plane
importance of expectation helps to avoid errors of judgement
