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Object colours, material properties and animal signals

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posted on 2023-06-09, 20:24 authored by Lucas Wilkins, Daniel Colaco OsorioDaniel Colaco Osorio
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.

History

Publication status

  • Published

File Version

  • Published version

Journal

The Journal of Experimental Biology

ISSN

0022-0949

Publisher

Company of Biologists

Issue

21

Volume

222

Page range

1-10

Department affiliated with

  • Biology and Environmental Science Publications

Full text available

  • Yes

Peer reviewed?

  • Yes

Legacy Posted Date

2020-01-27

First Open Access (FOA) Date

2020-11-07

First Compliant Deposit (FCD) Date

2020-01-27

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