Cuttlefish see shape from shading, finetuning coloration in response to pictorial depth cues and directional illumination

Zylinski, Sarah, Osorio, D and Johnsen, Sonke (2016) Cuttlefish see shape from shading, finetuning coloration in response to pictorial depth cues and directional illumination. Proceedings B, 283 (1826). ISSN 0962-8452

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Abstract

Humans use shading as a cue to three-dimensional form by combing lowlevel information about light intensity with high-level knowledge about objects and the environment. Here, we examine how cuttlefish Sepia officinalis respond to light and shadow to shade the white square (WS) feature in their body pattern. Cuttlefish display the WS in the presence of pebble-like objects, and they can shade it to render the appearance of surface curvature to a human observer, which might benefit camouflage. Here we test how they colour the WS on visual backgrounds containing two-dimensional circular stimuli, some of which were shaded to suggest surface curvature, whereas others were uniformly coloured or divided into dark and light semicircles. WS shading, measured by lateral asymmetry, was greatest when the animal rested on background of shaded circles and three-dimensional hemispheres, and less on plain white circles or black/white semicircles. In addition, shading was enhanced when light fell from the lighter side of the shaded stimulus, as expected for real convex surfaces. Thus, the cuttlefish acts as if it perceives surface curvature from shading, and takes account of the direction of illumination. However, the direction of WS shading is insensitive to the directions of background shading and illumination, but instead the cuttlefish tend to turn to face the light source

Item Type: Article
Schools and Departments: School of Life Sciences > Biology and Environmental Science
Subjects: Q Science > QL Zoology > QL0750 Animal behaviour
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Depositing User: Daniel ColacoOsorio
Date Deposited: 11 Apr 2016 15:51
Last Modified: 07 Mar 2017 06:23
URI: http://sro.sussex.ac.uk/id/eprint/60398

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