Understanding the rules of life

Category: Standard Studentships

Individual Differences in Human Colour Processing

Project No. 2482


Primary Supervisor

Dr Christoph Witzel – University of Southampton


Dr Jenny Bosten- University of Sussex

Dr Nick Kelley – University of Southampton


A major problem in colour research has been that we do not understand what determines perceived colours and how they are related to known neural mechanisms of vision.

To address this, we exploit an innovative approach that tests models of perceived colour by using individual differences. Complementary colours are key for understanding colour perception as they allow for testing when and how in the visual processing hierarchy different sources of complementary colours should arise. We will conduct a series of experiments that allow us to probe complementary colours at different stages of processing in different individuals that have different cone receptors and thus are predicted to have different complementary colours. In a first study, we will measure complementary colours (induced by both spatial context and as after-images) for a large sample of participants to arbitrate between different computational models of physiological mechanisms. In a second study, we will manipulate physiological differences by investigating anomalous trichromats, i.e., individuals with 3 cone types that differ from the norm. We will sequence the genes underlying the cone photopigments to generate testable predictions for complementary colours in particular individuals. In a third study we will measure steady-state visually-evoked potentials (SSVEPs) gathered using both electroretinogram (ERG) and electroencephalogram (EEG) to identify the locus of complementary colours along the visual processing cascade, from the retina to different stages of cortical processing. The outcome will be key to understand the fundamentals of colour processing and to any research and applications in art and industry that involve colour.

Ideally the applicant would have programming skills (e.g., Matlab), theoretical knowledge on perceptual colour processing, and/or technical experience with calibrating experimental set-ups for perception research; as a minimum, they should be ready and motivated to acquire these competences throughout the project.‚Äč