2. Colour Vision: A Biological Lens

About this Lecture

Lecture

In this lecture, we think about the biological approach to understanding colour vision, focusing in particular on: (i) the three different types of cone cells, each with their own colour spectrum to which they respond; (ii) why men are far more likely to be colour blind than women, due to them only having one X chromosome (the holder of the ‘colour gene’); (iii) the Ishihara test as a measure of colour blindness; (iv) people with ‘super’ colour vision, called tetrachromats, who have a fourth type of cone cell; (v) newly developed tests being performed in laboratory conditions to test for tetrachromacy.

Course

In this course, Dr Alex Mitchell (University of Edinburgh) explores visual perception from both a biological and a cognitive perspective. In the first lecture, we think about what perception psychology is and how the biological structure of our eyes and visual systems in the brain enable us to see. In the second lecture, we think about the biological approach to understanding colour vision and tetrachromacy. In the third lecture, we think about the cognitive approach to understanding colour vision, with a specific focus on the role of language in impacting our visual experiences and expression. Next, we think about brain damage, with specific focus on the role of lesion studies and the double dissociation method for establishing causation. In the fifth and final lecture, we think about the nature nurture debate in vision, looking at Morton and Johnson’s research on infant facial recognition and Pettigrew’s research into new-born kitten visual stimuli exposure.

Lecturer

Dr Alex Mitchell is a teaching fellow in the Department of Psychology at the University of Edinburgh. Dr Mitchell specialises in understanding human vision, specifically how what we see, as well as how changes in the brain caused by damage or neurodegeneration, affects how we interact with our world, using numerous brain-scanning technologies to complete her research, including fMRI and MEG. Some of Dr Mitchell's recent publications include 'Pseudoneglect is reliable across time but not task’' (2020), 'Assessment of visually guided reaching in prodromal Alzheimer’s disease: a cross-sectional study protocol' (2020), and 'Peripheral reaching in Alzheimer’s disease and mild cognitive impairment' (2022).