First 756 words of the document:
`Discuss the nature nurture debate in relation to perception' (25 marks)
The nature nurture debate in relation to perception falls in between both Gregory's and
Gibson's theories of perception and how we perceive objects.
Gregory's theory of perception falls on the nurture side of the perception debate. Which he
emphasises the idea that perception is based on three things. The first is sensory data, this is
what we see on the back of the retina, and Gregory argued that this isn't a complete view as
we then have to use our previous knowledge to know what the expectations and previous
ideas are, lastly we have to form a hypothesis based upon the two so the association
between the two causes you to form an image.
Gregory's theory is on the side of nurture as we instinctively do not know what we are
seeing until we put it to previous knowledge this depends upon upbringing and the
surroundings that you see. This was shown through the MullerLyer illusion by which we
appear to see a shorter line as it looks like a corner of a house as we are used to seeing thus
showing us some depth. When in face both of the lines are the same size thus the image we
actually see is the same size as the other line however due to previous depth knowledge
what we actually see is the application the line has to houses and buildings thus we see the
line relative to the context.
Khorasani (2007) found that once the person knew the illusion then it didn't work as well
thus could be used in support of the argument as our role of previous knowledge would
change as we know that that is not the case and that it is an illusion.
Bruner and Minturn (1955) showed that the digits 1 and 3 will be perceived as the letter B if
displayed within a set of letters but as 13 when in a set of numbers.
Visual illusions offer main support for this theory. Segall et al (1963) found that people who
do not live in carpentered environments (i.e. they live in round huts) are less likely to
perceive differences in the lengths of the lines of the illusion as they are not used to seeing the
edges of buildings or the corners of rooms thus showing the idea once again it is based
upon the idea of nurture and not nature otherwise all people would see the illusion in the
The indirect approach does explain the way our perceptual system deals with ambiguous
situations where the retinal image is poor. However most of studies are done in an artificial
set up therefore fails to explain our own realworld perception.
Countering Khorasani the theory fails to explain why we continue to see visual illusions even
though we know that they are illusions and that our brain is misleading us.
Lack of precision regarding key concepts, the notion of perceptual hypotheses may appear
to make sense, but there are unanswered questions, i.e. Marr (1982) asked what
determines information is selected from the retinal image?
Gibson theory of perception works on an opposite premise to Gregory's by which he
explains that we have enough information innately to work out what an image presents to us.
Gibson believed that we must study our perception in a real environment in order to work
out how it works e.g. we have to incorporate texture in working out the object thus coming
up with the texture gradient by which the further away you move from an object the less
gradient and more smooth the object appears to be by which we see through optic arrays.
Also to fully work out what is within the environment, the idea of invariant perception by
which the perceiver has to move around the environment as the head and vision is moving all
of the time thus need to see the variants within that in order to work out how it works.
The fact that we can perceive depth and size etc according to Gibson is down to the horizon
ratio this is the idea that there is a measure by which we look at proportions of other people
Other pages in this set
Here's a taster:
Gibson uses optic flow as objects that are directly closer to us appear to be moving at a
slower rate than objects in the background appear to be thus giving allowances for objects
that could only be moving alongside the natural head movements that a person may make
rather than the more exaggerated movements towards the background.…read more