Each question was marked on the standard departmental 10-point scale and score out of 30 resulted. These scores were then rescaled to give a mark out of 10 using the table below. The mean score was 6.
Final Mark Actual Score Number of Students
/10 /30 2011 + 2031 = 184
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2 5, 6 3
3 7, 8 2
4 10, 11 10
4.5 12, 13 21
5 14, 15 28
5.5 16, 17 34
6 18 24
6.5 19 10
7 20 13
7.5 21 16
8 22, 23 9
8.5 24 5
9 25 5
9.5 26 2
10 27 2
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The scores on each question, your mark out of 30 and your rescaled mark out of 10 are listed next to your ID number on the noticeboard. If your student ID is not listed, or you disagree with your late penalty or you have a missing value listed as your mark, please see Cheryl Roberts.
General comments on answers to each question are listed below. If the general comments are not sufficient feedback, you may make an appointment with Lisa Wise to go through individual papers.
This question required that you describe the aspect of the stimulus that gives rise to colour sensations (i.e. refelcted light of the appropriate wavelength, which will be limited by the illuminating light and by the surface pigments and opacity of the object) and that you described the neural system which receives the colour stimulus. If you described the neural system, both the trichromacy of the receptors and the colour opponency of neurons should have been described. Colour contrast effects and colour constancy were also important.
I accepted any reasonably coherent description of most of the above as passable, with higher marks going to people who actually crafted an answer to the question rather than a catalogue of everything relevant to colour coding. Although Isaac Newton made some important discoveries, his specific words in describing dispositions of things became a little tedious and could easily have been paraphrased !!
3, 4 Answers which either were factually quite wrong, or didn't
answer the question sufficiently (ie listed a subset of the
above, but without in anyway suggesting how the catalogued
information related to the question).
5, 6 Answers which merely catalogued the physics of light and
processing of colour by photoreceptors and colour
opponent cells and/or mentioned colour constancy
7, 8 Answers which drew attention to the relevance to the argument
of the information they provided
9, 10 As above, but with clear line of argument
If you were in the 7-10 range of mark but made factual errors, you lost a mark.
This question was supposed to be a "gimme", but proved extremely difficult for many students. I was genuinely surprised at the trouble students had in determining what a visual anatomy and physiology is about.
Anatomists study structure - so in the visual system this would involve the structure of the eye (which most students stated), but also the structure and connectivity of the visual pathway. Anatomists can use a range of sophisticated histological techniques to map out connections from the eye to the brain and to look at the arrangement of cells and connections within each visual area within the brain. The pattern of connections from various visual areas can suggest important things about function. Anatomy determines the constraints of a system, and can also give insights about function.
Physiologists study function - and visual physiologists tend to look at the responses of brain cells to visual stimuli (eg they plot visual receptive fields of brain cells to a variety of stimuli in a variety of contexts). They also look at neurochemical influences within the visual system, as well as functional properties of the eye and its associated structures.
It was not enough to say that anatomy and physiology are very important, and help us understand how the brain works. I was looking for some examples of what anatomy and physiology might contribute to our understanding of (visual) psychology.
A number of people interpreted the question as asking how vision per se might contribute to understanding of psychology in general - I accepted this interpretation, but it didn't change the requirement of describing anatomy and physiology - it just lead to the choice of examples being a little broader than I had envisaged. A number of people who answered the question in this way actually did not talk about visual neurobiology, but rather talked about visual psychophysics, without realising that this is psychology not anatomy/physiology.
I was a little disturbed at the lack of confidence in providing a "common-sense" answer to this question from your reading of the text and listening to lectures. Many people tried to find a section of a book or lectures that talked about anatomy (thereby generally listing each structure of the eye and what it does, but without telling me anything about how this affects psychology) and physiology (usually Herman's Grid and lateral inhibition). The information so derived did not generally form an answer to the question in any coherent way.
3, 4 Answers which either were factually quite wrong, or didn't
answer the question sufficiently
5, 6 I reluctantly accepted the statement that anatomists would
study the structure of the eye and that physiologists would
study the function of the eye, each with some details to be
sufficient given that a relationship to understanding psychology
was included.
7, 8 The basic answer I had expected became a higher level answer -
ie, it incorporated a better description of the sort of job an
anatomist or physiologist might do with the visual system.
9, 10 As above, but with serious consideration of the different focus
of each discipline and how this ties in with an understanding
of psychology.
This question allowed a description of the field of view afforded by frontal vs lateral eye locations, including the fact that the frontal eye position results in significant binocular overlap, providing a possibility for stereopsis. Lateral eye position requires use of motion parallax (which, contrary to popular opinion, is a good cue to depth and is no more absolute than stereopsis).
Many people used this question as an opportunity to tell me everything they knew about stereopsis, and I accepted answers on stereopsis as passable even when they didn't really answer the rest of the question. Marks started disappearing when people attempted to describe the disadvantages of stereopsis, rather than the disadvantages of a frontal eye position.
A number of people made a claim that frontal eye position because it was more limited in view would render you more susceptible to the loss of an eye, rather than recognising (as some others did) that loss of an eye for a lateral-eyed animal would lose them a far greater percentage of their field of view.
Much has been made of the predator/prey relationship such that stereopsis allows predators accurate depth perception without moving their heads (although you get motion parallax cues through eye movements without head movements if you so desire). Many people lost marks for flawed evolutionary arguments: the eye of the human didn't gradually migrate from the side of the head to the front in order for the human to become a better predator, and it won't migrate back again now that we don't hunt regularly !!! Nobody mentioned that stereopsis also is useful in developing tool use (which is supposed to have been important in evolutionary terms). Along the same lines, we did not develop stereopsis in order to identify counterfeit bank notes - it is a consequence of having stereopsis, not a driving force in its development.
3, 4 Answers which either were factually quite wrong, or didn't
mention disadvantages of frontal eyes or mention the
alternative arrangement.
5, 6 Answers which merely described stereopsis, and mentioned
lateral eyes and lack of depth (actually not correct)
7, 8 Answers which described the field of view of frontal vs
lateral eye placement, described stereopsis, compared it
with motion parallax and mentioned the predator/prey
comparison.
9, 10 As above, but with better clarity of argument
Marks were lost for poorly reasoned evolutionary arguments, or for claims that motion parallax is no good, or for incorrect descriptions of stereopsis.