Perception Flashcards
Definition of sensation
Physical stimulus of 5 senses processed by sense receptors
Definition of perception
Interpretation and organisation of sensory information
Difference between sensation and perception
S-detection of stimulus
P-interpretation of stimulus
Visual Cue
Information about distance, movement etc
Visual Constancies
Seeing the object the same from different angles and distances
Binocular depth cues are with
Two eyes
Retinal disparity definition and what type of cue
Binocular depth cue
View from right and left eye are different. The larger the difference the closer the object
Convergence definition and what type of depth cue
Binocular depth cue
The eyes point together when an object is closer causing strain on the eye muscles. The more the strain, the closer the object.
Monocular depth cue definition
One eye
Height in Plane is what type of depth cue and definition
Monocular depth cue
Objects higher up in a visual field are perceived as being further away
Relative size definition and what type of depth cue
Monocular depth cue
Smaller objects in a visual field are perceived as being further away
Occlusion definition and what type of depth cue
Monocular depth cue
If an object is obscured then the obscured object is perceived as being further away
Linear Perspective definition and what type of depth cue
Monocular depth cue
Parallel lines in the distance appear to get closer together and eventually join
Size Constancy explains visual illlusion because
Objects are perceived as a constant size although the size on the retina changes with distance
Misinterpreted depth cues explains visual illlusion because
Objects in the distance are scaled up by the brain to look normal size
How does the Alonzo illusion and Mueller - Lyer Illusion support misinterpreted depth cues
Ponzo illusion - converging lines give illusion of distance. We mentally enlarged the top line.
Mueller - Lyer illusion - ingoing fins shape the outside building so it appears closer and scaled down .
Ambiguous Figure explains visual illlusion because
It means that there are two possible interpretations and the brain can not decide which is correct so alternates
How does the Necker Cube and Rubin’s Vase supports Rubin’s vase
Necker cube -cube can be seen as pointing to the right or downward to the left
Rubin’s Vase - faces and vase
Fiction explains visual illlusion because
Seeing something that’s not there
How does the Kanizsa triangle support fiction
Illusion creates and impression of a second triangle
Gibson’s direct theory of perception
Sensation is perception
Our eyes are highly developed so we do not need to use past experiences to infer from
Motion parallax is another monocular depth cue helping us judge distance in everyday life
Nature not nurture
One strength of Gibson’s theory is that it was developed using research with pilots in the real worl
This means his explanation of movement and depth were very detailed.
Has real world relevance so successfully explains how we perceive the world daily
One weakness of Gibson’s direct theory is that doesn’t explain perceptual errors clearly
According to Gibson all we need to perceive the world is the rich information received at our retina however visual illusions are good examples of perceptual errors which draws our brain to the wrong conclusions. Not as helpful as Gregory’s theory
Another strength is that research with young infants supports Gibson’s direct theory
A visual cliff experiment in which infant were asked to crawl across a fake cliff found that even when their mothers encouraged them they had an innate ability to perceive depth. Some parts of perception are probably innate
Gregory’s constructivist theory
Perception is a construction
We infer most of the world as most of it is ambiguous and incomplete
Visual cues from the brain help is perceive depth and distance
Past experiences influence the sophistication of our perceptive skills
Nurture not nature
On strength from Gregory’s constructivist theory is that studies show cultural differences in perception
Hudson’s study shows that different experiences have affected the participants perception and that nurture plays a key role in helping us understand the world around us
Cultural differences are better explained by Gregory than Gibson
One weakness of Gregory’s constructivist theory is that, even though it is supported by our understanding of visual illusions it is an unusual example of perception
Gregory’s idea is that illusions rely on misinterpreted depth cues and size constancy. However these artificial 2D images are deliberately designed to fool us and may not tell us much about perception in the real world
Gibson’s theory is better in this aspect
Another weakness of Gregory’s theory is that it can not explain how perception gets started in the first palace
Many studies show evidence of at least some perceptual ability in babies so not all perception is a result of nurture
Also the variety of differences in perception due to culture are not very large so Gregory’s theory struggles to explain examples of innate perception.
What is a perceptual set
The force that makes our brain to notice certain aspects of the sensory environment
Hudson’s study aim
Do people in different cultures interpret information differently through depth cues
Hudson’s study method
Showed 2D drawings to native black South Africans who were schooled and unschooled and to white Europeans who were schooled and unschooled . They were asked to what do they see? What is the man doing? And which is nearer tha man, elephant or antelope
Hudson’s study results
Both black and white schooled participants were more likely to perceive depth than unschooled participants,
White schooled participants were more likely to perceive depth than black schooled participants,
Hudson’s study conclusion
People from different cultures (schooling and race) perceive depth cues differently - shows that some aspects of perception are learned and this supports Gregory’s constructivist theory
One weakness with Hudson’s study is that cross cultural research is that the task and instruction may not make sense to them
Language barriers means translators may be used and that can skew a question differently. Affects the validity
Another weakness with Hudson’s study is that some participants may have been confused by seeing 2D drawings
Many African participants hadn’t seen paper before so this affects the validity of the results
Another weakness with Hudson’s study is that it is very old so may be poorly designed
Less sophisticated and well recorded so may affect the quality of the results
McGinnies study aim
Whether things that cause anxiety are less likely to be noticed than things are emotionally neutral. In particular does it take us longer to recognise words that may cause us embarrassment
McGinnies method
Eight male and eight female participants and were shown a series of words that flashed on a screen. As soon as they saw the word they had to recognise it and and say it. At the same time their GSR which records their emotional response
McGinnies Results
McGinnies noticed that participants took longer to recognise the offensive words and that the taboo words caused s higher elevation in GSR.
McGinnies Conclusion
Suggests that emotion is a factor in perceptual set. Higher anxiety levels associated with taboo words s,odd down recognition which McGinnies refers to perceptual defence. Which blocks the information that causes anxiety or embarrassment for even just a moment
One strength of McGinnies study is that it used an objective measurement
Many studies of perceptual studies are limited because they are based on self report methods however McGinnies uses a GSR so it is not biased
One weakness of McGinnies is that delayed recognition may be more to with embarrassment than defence
Th Elon get time taken to identify taboo words is that it could be hesitation from participants due to embarrassment than defence.
Awkwardness is an extraneous variable which affects the validity of the results
Another weakness of McGinnies kx that studies are emotion and perceptual set is that the restarts are contradictory
Sometimes they suggest we are more likely to notice emotional material and sometimes we are less likely to notice it
It doesn’t tell us why we sometimes us perceptual defence and other times don’t
Makes it difficult for psychologist to predict behaviour
Bruner and Minturns study aim
Whether expectation is an important factor is perceptual set
Bruner and Minturns method
An independent design where participants were presented with a sequence of letters and numbers. The ambiguous figure B could be seen as 13 or B.
Bruner and Minturns study results
Those who saw the sequence of letters, they were likely to figure as being of the letter B
If they saw the sequence of numbers they said it was 13
Bruners and Minturns conclusion
Shows that expectation off why the figure was represented was affected by the context that figure was presented in.
One weakness of Bruner and Minturns study was that an artificial task was used
An ambiguous figure is designed to trick our perceptional abilities hence lacks validity .
Another weakness of Bruner and Minturns study is that it used an independent design
Mean participant differences could have acted as an extraneous variable that skewed the results and their validity
One strength of Bruner and Minturns study is that it can be applied to real life
It can explain errors such as mistaking an commercial aircraft as an enemy aircraft because of expectations. Hence this explains why serious mistakes may be made in the real world
Gilchrist and Newburgh aim
If food deprivation affects the perception of food pictures
Gilchrist and Nesburgh method
Two groups of student one deprived for 20hrs of food the other a control group. They were shown four slides of meal. They were then showed the pictures again but dimmer and the participants had to adjust the brightness
Gilchrist and nesberg results
Participants perceived the food as brighter if they were deprived of food
Gilchrist and nesberg cmonclusion
Being deprived of food increases perceptual sensitivity
Shows hunger is a motivating factor affecting the perception of food
One strength of gilchrist and nesberg is that similar studies support this
Sanford deprived participants and showed them ambiguous pics. The longer they were deprived of food the more likely they perceive the ambiguous pictures as food
Increases validity
One weakness of gilchrist and nesberg is that many feel this type of studies are unethical
Because depriving participants of food and water causes distress and is partially a violation of human rights.
Another weakness with gilchrist and nesberg is that it doesn’t apply to everyday life
Participants were asked to judge pictures of food rather than actual food which makes it harder to apply the results to other situations.
