Object colours, material properties and animal signals

Wilkins, Lucas and Osorio, Daniel (2019) Object colours, material properties and animal signals. The Journal of Experimental Biology, 222 (21). pp. 1-10. ISSN 0022-0949

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Humans and other animals often use colour to recognise objects regardless of their context – as a measure of material properties rather than of their contrast with a background. Most work on visual communication signals is, however, concerned with colour differences, typically scaled by just noticeable differences (JNDs). Here, we move from the prevailing physiological framework to understand what a given colour or type of colour might tell an animal about an object. To this end, we consider the properties of object colour solids, which represent the colour gamut of reflective materials for a given type of animal eye. The geometry of colour solids reveals general relationships between colours and object properties, which can explain why certain colours are significant to animals, and hence evolve as signals. We define a measure of colour vividness, such that points on the surface are maximally vivid and the ‘grey’ centre is minimally vivid. We show that a vivid colour for one animal is likely to be vivid for others, and highly vivid colours are less easily mimicked than less vivid colours. Furthermore, vivid colours such as black, white, red and blue, as well as pale colours and certain unsaturated shades, are produced by pure or orderly materials. Such materials are created and maintained against entropic processes. Vivid colours are therefore indicative of ecological affordance or biological function, so it is valuable to have low-level psychological biases towards these colours regardless of any specific significance they might have to the receiver.

Item Type: Article
Keywords: Colour theory, Colour, Colour solid, Receiver psychology
Schools and Departments: School of Life Sciences > Biology and Environmental Science
Subjects: Q Science > QH Natural history > QH0301 Biology > QH0359 Evolution
Q Science > QL Zoology > QL0750 Animal behaviour > QL0776 Communication
Q Science > QZ Psychology
Depositing User: Daniel ColacoOsorio
Date Deposited: 27 Jan 2020 11:07
Last Modified: 15 Mar 2022 13:15
URI: http://sro.sussex.ac.uk/id/eprint/89597

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