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10 Cards in this Set
- Front
- Back
Depth Perception and Visual Constancy |
Depth Perception (DP) is our ability to assess how far objects are from ourselves. Both monocular cues (e.g. motion parallax and occlusion) and binocular cues (e.g. retinal disparity) combine in helping achieve DP. |
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Depth Perception |
36 infants (6-14 months) were placed on the centre board of the visual cliff. All the infants were able to crawl (independent locomotion). Each child was then observed to see if it would crawl to the mother (cross onto the deep side) or if it would crawl onto the shallow side (away from the mother). 3/36 crossed onto the deep side, 27/36 moved onto the shallow side, 6/36 remained on the centreboard. G&W concluded infants had DP by the time they had independent locomotion. |
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Visual Constancy |
BOWER (1966) found that two month old infants were capable of shape constancy. Using operant conditioning, the infants were postively reinforced whenever they were shown a rectangle at 45 degree angle. When tested they still showed a preference for the rectangle (now presented at a different angle) over that of a trapezoid which cast the same retinal image of the original rectangle. |
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Depth Perception & Visual Constancy |
- Infants are unable to report what they can and can't see, therefore the development of techniques such as the visual cliff and habituation may be ingenious ways of getting around this issue, but they still rely on the researchers observing and interpreting the infants behaviour, which may be affected by researcher expectation and bias. |
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Depth Perception & Visual Constancy |
When using Infant studies to assess if perception is a feature of nature or nurture, most research tends to indicate many perceptual skills like DP and VC are present from birth. This therefore supports a more bottom-up way of processing and that indeed perception is innate. HOWEVER the visual acuity of an infant is incredibly poor and so it is unclear if any perceptual skills are purely the product of maturation or are a combination of both nature and nurture. Campos, for example, found two month olds could detect depth when placed on the deep side of the visual cliff (nature), but that they only developed a fear reaction of the deep side it when they were 9 months. Infant research suggests that nature may give us perceptual abilities, but that nurture is required for us to make best use of them. |
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Depth Perception |
HUDSON (1960) showed pictures of a man pointing a spear at an elephant and antelope to European and Bantu children in South Africa. The pictures used visual cues, such as linear perspective and occlusion. At the start of Primary school, all the children had problems using the depth cues, however by the end of Primary School, nearly all of the European children were able to assess the pictures correctly, but many of the Bantu were unable to interpret the depth cues. |
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Visual Constancy |
SEGALL (1963) exposed American, European and Zulu individuals to the muller-lyer illusion. Segall found that the Zulu were much less likely to be affected by the illusion. He explained this because at the time the Zulu lived in circular huts and had therefore not had the experience of a 'carpentered world'. |
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Depth Perception & Visual Constancy |
- The use of pictures and illusions e.g.the trapezoid window illusion may be an example of an 'imposed etic'. The Zulus' lack of ability to see the illusion may just mean that the illusion makes no sense to them NOT that they don't have shape constancy. |
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Depth Perception & Visual Constancy |
Most early CCR in the 1950s and 1960s suggested that experience affected perceptual abilities, supporting a more environmental explanation and nurture position. However, more recent research has found fewer cultural differences, possibly because more modern research does not have as many of the methodological flaws seen in earlier research. |
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Depth Perception & Visual Constancy |
Although NHAs have been used in perception research for some time, such as G&W's research. The use of NHAs has now really superseded both using infants and cross-cultural studies in assessing the development of perceptual abilities. Research such as Blakemore & Cooper and Hubel & Wiesel have concluded that innate visual mechanisms are shaped by experience, suggesting nature and nurture. |