Dr. Semir Zeki
Professor of Neuroaesthetics, University College London (UCL)
Title: Colour Vision: How colours are generated in the brain
Date: Wednesday, 16th March 2022
Time: 05:00 pm (IST)
Link: https://bit.ly/36qNsOd
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Abstract
My close involvement with colour vision since the early 1970s has shaken my belief in concepts of colour vision inherited from the past, and in particular its two pillars – The Young Helmholtz Trichromatic Theory and the Ewald Hering Opponent Colours Theory. I do not regard the former to be a theory of colour vision but rather a theory of the organization of sensory receptors to enable an individual to sample a wide variety of visual experiences, including colour but not limited to it. Equally, I do not regard opponency as providing a basis for generating perceived colours, including opponent colours. Rather, opponency works on the broad absorption spectra of the cones to generate cells with sharper spectral sensitivities, which can be used to detect many features of the visual world, not limited to colour. A strong, and almost universal belief in Trichromacy and Opponency as being specifically colour theories, coupled to a complex terminology derived from them has, I believe, hindered us significantly from pursuing the single most important feature of colour vision, namely how colours, and constant colour categories, are generated in the brain to give us constant knowledge of the characteristics of surfaces against a background of continually changing illumination conditions in which they are viewed.
About the Speaker
Semir Zeki is a neuroscientist whose early work on the visual cortex showed how the brain processes features such as colour and movement through distinct brain areas. His interest in art and vision has led him to explore the brain mechanisms underlying human responses to beauty, a field for which he coined the term ‘neuroesthetics’. He is a fellow of the Royal Society and is the recipient of numerous awards including the King Faisal International Prize in Biology (2004), the Erasmus Medal (2008), and the Aristotle Medal (2011).