unit 2 - perception Flashcards
sensation
physical stimulation of the sensory receptors is processed by sense receptors which our brain interprets to lead to perception
perception
the organisation and interpretation of sensory information
what is the difference between sensation and perception
sensation is the detection of a stimulus in the environment
perception is the brain interpreting and understanding these sensations
visual cues
features of the environment that give us information about movement, distance etc.
visual constancies
seeing objects as the same despite seeing them from different angles and distances
give two examples of binocular depth cues
retinal disparity
convergence
what is retinal disparity
each eyes sees things differently as they are positioned about 6cm apart on the face
retinal disparity is the difference between the left and right eye’s view which the brain receives to give information about depth and distance
what is convergence
our eyes converge/become closer together when objects get closer to us
muscles around our eyes work harder when objects are close and this information is sent to the brain to give information depth and distance
give four examples of monocular depth cues
height in plane
relative size
occlusion
linear perspective
what is height in plane
objects that are higher up in the visual field appear to be further away
what is relative size
smaller objects in the visual field appear further away
what is occlusion
objects that are in front of other appear closer to us whilst objects behind other objects seem further away
what is linear perspective
when parallel lines converge in the distance, the point at which they come together is perceived to be further away
what are the 4 main explanations for visual illusions
size constancy
misinterpreted depth cues
ambiguous figures
fiction
describe size constancy as an explanation for visual illusions
the brain perceives familiar objects as a constant size despite the size of the image they produce on a our retina changing with distance
describe misinterpreted depth cues as an explanation for visual illusions
objects in the distance that appears smaller are scaled up by our brain so that they look normal size
sometimes the brain perceives distance where there isn’t any which creates a visual illusion
describe ambiguous figures as an explanation for visual illusions
a type of visual illusion where there are two possible interpretations of the same image, and the brain cannot decide which one to choose
describe fiction as an explanation for visual illusions
a type of visual illusion that causes the brain to perceive something that is not there
give 6 examples of visual illusions
Ponzo illusion Müller-Lyer illusion Necker cube Kanizsa triangle Ames room Rubin's vase
explain Ponzo’s illusion
MISINTERPRETED DEPTH CUES
converging lines creates the illusion of distance - the brain uses SIZE CONSTANCY and mentally scales up the more distant line and scales down the closer line
explain Müller-Lyer illusion
MISINTERPRETED DEPTH CUES
ingoing fins are shaped like the outside of a building and outgoing fins are shaped like the corner of a room stretching away from us
this gives the illusion of distance and so we mentally scale up the line that appears further away (outgoing fins) so it appears longer
explain Necker cube
AMBIGUOUS FIGURES
the same image of the cube can be perceived as pointing upwards to the right or downwards to the left
explain Kanizsa triangle
FICTION
illusory contours create the impression that a second triangle is overlapping the first one
explain Ames room
MISINTERPRETED DEPTH CUE
explain Rubin’s vase
AMBIGUOUS FIGURE
the image can either be perceived as a vase or two faces staring at each other
describe Gregory’s constructivist theory of perception and the 4 main parts
proposes that we use past experience to make sense of the world around us
perception is a construction - the brain uses incoming information from our eyes as well as using information that we already know about the world
inference - the brain uses sensory information that is available and then fills in the gaps, past experience allows us to infer what should be there
visual cues - when making inferences, features of the environment gives the brain information about depth, distance etc.
past experience - perception depends on experience which is learned, the more we interact with the world, the more sophisticated our perception becomes
give 3 evaluation points of Gregory’s constructivist theory of perception
STRENGTH - supported by research in other cultures
WEAKNESS - explains visual illusions but may not tell us much about wider world
WEAKNESS - doesn’t explain how perception begins
describe a strength of Gregory’s constructivist theory of perception
- the theory has good support from studies that show cultural differences in perception
- research is different parts of the world has found that people interrpet visual cues differently
- this suggests that their different experiences have affected their perception and perception is learned
describe two weakness of Gregory’s constructivist theory of perception
- Gregory’s use of visual illusions to support his theory is a weakness
- they are artificial 2D images that are deliberately designed to fool us so his theory may not tell us much about perception in the real world
- Gregory’s theory can’t explain how perception begins in the first place
- research (Fantz) showed that babies have some perceptual abilities at birth, preferring human faces over random patterns
- this suggests that perception is not all the result of our experience
describe Gibson’s direct theory of perception and the 4 main parts
suggests that the environment gives us all the information we need for perception
direct perception - sensation and perception are the same thing, we don’t need past experience to interpret what we see
optic flow patterns - when moving, the point which we are moving towards remains stationary and everything else moves away from it, this is detected by our eyes and tells our brain that we are moving so we know our speed and direction of travel
motion parallax - a monocular depth cue which tells the brain the speed at which we are moving - objects closer in our visual field appear to move faster than objects further away
influence of nature - our ability to perceive is innate
give 3 brief evaluation points of Gibson’s direct theory of perception
STRENGTH - the theory has real world meaning
STRENGTH - scientific evidence from studies of babies
WEAKNESS - struggles to explain visual illusions
describe two strengths of Gibson’s direct theory of perception
- the study has real world meaning as the research was based on the experience of pilots from the second world war
- this makes it more relevant to explain how we perceive the world on a daily basis
- the theory is supported by scientific evidence in terms of the role of natures
Gibson and Walk’s study found that very few infants would crawl off a visual cliff suggesting that they were born with an ability to perceive depth which shows that some perception is innate
describe one weakness of Gibson’s direct theory of perception
- the theory struggles to explain visual illusions
- Gibson proposed that we will always perceive accurately but illusions trick the brain into misperceptions which suggests that there is more to perception than his theory suggested.
what are the 4 factors that can affect perception
expectation
motivation
culture
emotion
perceptual set
the tendency of our brain to notice certain aspects of the sensory environment more than others
culture
the social world that surrounds you
who investigated the effect of culture on perceptual set
Hudson
aim of Hudson’s study
to find out whether people from different cultural/education backgrounds perceived depth cues in 2D images differently
method of Hudson’s study
- showed 2D drawings to South African participants (native black people who were either schooled or unschooled and white people of European descent who were either schooled or unschooled)
- participants had to say which animal the man was trying to spear
- the spear pointed to an elephant and an antelope by depth cues suggested that he was really pointing at the antelop
results of Hudson’s study
despite the picture using height in the visual field and relative size, many believed the spear to be pointing towards the elephant
schooled participants were more likely to perceive depth than unschooled participants
white schooled participants were more likely to perceive depth than black schooled participants
conclusions of Hudson’s study
people from different educational/cultural backgrounds use depth cues differently and have a different perceptual set supporting Gregory’s theory that perception (depth cues in this case) is learned
give three brief evaluation points of Hudson’s study
- WEAKNESS the instructions may not make sense
- WEAKNESS some of the participants may have been confused by seeing drawings on paper
- WEAKNESS the research is from a long time ago and may be poorly designed
explain the 3 weaknesses of Hudson’s study
- instructions may not have made sense due to a language barrier meaning translations of the methods may have been unclear which affects the validity of the results
- some of the participants may have been confused seeing drawings on paper because when they were shown images on familiar materials such as cloth, they gave different answers ; showing that representation affects results
- the research is from a long time ago and may be poorly designed as early cross cultural studies of perception often did not include proper control group which causes the results of cross cultural differences in perception to lack validity
who investigated the effect of emotion on perceptual set
McGinnies
aim of McGinnies’ study
to see whether things that cause anxiety are less likely to be noticed than things that are emotionally neutral
method of McGinnies’ study
8 male and 8 female students were shown neutral and offensive ‘taboo’ words which flashed on a screen
after each word was shown, participants had to say it aloud
the amount of emotional arousal was measured through galvanic skin response (GSR) which records the electrical changes in the skin
results of McGinnies’ study
participants took longer to say offensive words like ‘bitch’ and ‘penis’ than neutral words such as ‘apple’ or ‘dance’
taboo words also produced bigger changes in the GSR than neutral words
conclusion of McGinnies’ study
emotion affects perceptual set
perceptual defence is used by the brain when confronted with words that are offensive or cause anxiety
give 3 brief evaluation points of McGinnies’ study
STRENGTH - used an objective measurement of emotion
WEAKNESS - delayed recognition may be more to do with embarassment than defence
WEAKNESS - studies in this area are contradictory
describe one strength of McGinnies’ study
the study used an objective measurement of emotion
they used a scientific method, the galvanic skin response to test biological anxiety responses which produces results that are less open to bias than rating scales, for example
describe two weakness of McGinnies’ study
delayed recognition may be more to do with embarrassment than defence
participants may have hesitated in giving their response as they were uncomfortable repeating rude words in a study suggesting that awkwardness may have been an EV
studies in this area have contradictory results because sometimes they suggest we are more likely to notice emotional material and sometimes we are less likely
what they do not tell us is why perceptual defence occurs in some situations and why perceptual sensitisation occurs in others
this makes it difficult for psychologists to draw firm conclusions
who investigated the effect of motivation on perceptual set
Gilchrist and Nesburg
aim of Gilchrist and Nesburg’s study
to find out if food deprivation affects the perception of pictures of food
method of Gilchrist and Nesburg’s study
two groups of students (independent groups) ; one deprived of food for 20 hours and a control group who were not hungry
students were shown four slides each showing a meal, each for 15 secs
the picture was shown again but dimmer and participants had to adjust the lighting to make it look the same as it did before
results of Gilchrist and Nesburg’s study
participants perceived the food as brighter the longer they were deprived of food for
the control group didn’t perceive the food as brighter
conclusion of Gilchrist and Nesburg’s study
being deprived of food increases perceptual sensitivity
shows that hunger is motivating factor that affects the way in which food related imaged are perceived
give three brief evaluation points of Gilchrist and Nesburg’s study
STRENGTH - similar studies have found similar results
WEAKNESS - studies in this area are unethical
WEAKNESS - not like everyday life
describe one strength of Gilchrist and Nesburg’s study
similar studies have found similar results
Sanford deprived participants of food and showed them ambiguous pictures ; the longer they were deprived of food, the more likely they were to see food
this increases the validity of this study’s results
describe two weaknesses of Gilchrist and Nesburg’s study
studies in this area are unethical because depriving participants of food and water could cause them to feel uncomfortable.
you should not do this in psychological research
this study was unlike everyday life because participants were asked to judge pictures of good rather than real food making it harder to apply the results to situations in the real world
who investigated the effect of expectation on perceptual set
Bruner and Minturn
aim of Bruner and Minturn’s study
to find out whether an ambiguous figure was seen differently if the context of the figure was changed
method of Bruner and Minturn’s study
an independent groups design was used where participants were either presented with a sequence of letters or a sequence of numbers with the same ambiguous figure in the middle
this figure could be perceived as the letter B or the number 13
participants had to report and also draw what they saw
results of Bruner and Minturn’s study
those who saw a sequence of letter were more likely to report the figure as being the letter B and were also more likely to draw a ‘B’
if shown numbers, they were more likely to say it was the number 13 and drew ‘13’
conclusions of Bruner and Minturn’s study
expectation of what the figure represented was affected by the context that the figure was presented in
give 3 brief evaluation points of Bruner and Minturn’s study
STRENGTH - the study has real life application
WEAKNESS - used an artificial task
WEAKNESS - there were individual difference between groups
describe one strength of Bruner and Minturn’s study
the study has real life application
it can explain errors that people make as the results suggest that expectations can influence perception, which helps to explain why people make sometimes serious mistakes on tasks in the real world
describe two weakness of Bruner and Minturn’s study
the study used an artificial task
ambiguous figures are designed to specifically trick perception which causes the results to lack validity
there were individual difference between groups because an independent groups design was used
this is an issue as differences in perception between the groups may have been due to participants variables rather their expectations
