PS1061: Sensation and Perception 2010

Alternative Assessment Instructions

" Describe and evaluate the two main theories of colour vision. "

(deadline: 09/12/2010)

Course co-ordinator: Johannes M. Zanker, j.zanker@rhul.ac.uk, (Room 214)


How do we perceive colour?

Isaac Newton's radical statement: “the rays, to speak properly, are not coloured. In them there is nothing else than a certain power and disposition to stir up a sensation of this or that colour” suggests a very interesting and most important relationship between the physics and perception of light - a property (colour) is constructed from light projected on the eyes which is not immedeately visible when just looking at the beam of light (rays).

When a beam of white light is split by a prism into a set of light beams of different monochromatic colours (see image), these colours are only visible if they are projected on a surface (or particles in the air, such as smoke).

Aims:

Context

The topic relates to a very old, and a most exciting, discussion about perception – how do we perceive colours – which attracted some of the brightest scholars, incuding Newton and Goethe, and many artists such as Albers. It also is connected to a number of practical applications, such as colour mixing, or colour illusions. Two 'classical' theories, trichromatic colour vision and opponent colour vision have been long discussed as mutually exclusive, but our current physiological knowledge of the visual system suggests ythat they coexist, by describing processing mechanisms at differnt levels of the visual processing stream. As such, the topic is an opportunity, also to get an idea how scientific progress has been achieved.

And here you can download your coursework essay standard information sheet...

What to do

Don’t worry, you don’t need to answer all questions related to this area of visual perception, and don't need to read all of the material mentioned in textbooks or listed below. All of the basic facts have been covered in lecture 3, and can be found in preception textbooks (see below). In particular, chapter 7 of Goldstein (2007) contains specific sections on trichromatic theory and opponent-process theory. The additional reading listed below is not compulsory but can be used to demonstrate that you expanded your understanding in depth in selected aspects. A 1500 word essay certainly can only scratch the surface, and therefore is meant to focus on a description of the two main theories, the perceptual evidence that supports each of them, and related neural processing. At the end of your essay, you should write a summary paragraph to evaluate the question whether any of these theories provides a unified and complete theory of colour vision, and you may also want to consider whether there are aspects of colour vision which are not captured by either of the theories. You will discuss more details of how you can approach this task in the coursework tutorial.

Have fun !

Sources

Please note that there currently is no textbook chapter or single review paper that has a focus on this topic, but the basic phenomena and some of the contexts are covered in the third lecture, and can be found on the lecture webpage (where you can also find further links to other webpages):

Starting from the lecture material, the best way forward is to browse chapter 7 of Goldstein’s ‘Sensation and Perception’ for more specific information about icolour vision, and/or the draft book chapter from Zanker (2010). Specific questions (but not general questions like 'what do i need to write in the essay?) can be raised with the course coordinator, and may be discussed on the student intranet forum. A deeper understanding of some of the topics can be derived from reading some of the texts listed below.

Some additional reading (available from virtual resources room, library or internet):

A note on Plagiarism

Plagiarism consists of a person presenting another person’s ideas, findings or work as their own by copying or reproducing the work without due acknowledgement of the source. The University regards plagiarism as a very serious offence. At the very least, it is a misuse of academic conventions or the result of poor referencing practice. Where it is deliberate and systematic, plagiarism is cheating.

By completing a declaration with the submission of your coursework, you are confirming in written form that the work you are submitting is original and does not contain any plagiarised material.

When plagiarism is suspected in any work, it will be scrutinized further in line with college policy. Furthermore, to assist with plagiarism detection the Department is implementing random checks of all coursework. We routinely check from the electronically submitted copies of coursework essays approx.10% of all submissions, selected at random.

back to course outline
last update 29-10-2010
Johannes M. Zanker