Abstract
Camouflage is the primary defence of many animals and includes multiple strategies that interfere with figure-ground segmentation and object recognition. While matching background colours and textures is widespread and conceptually straightforward, less well explored are the optical ‘tricks’, collectively called disruptive colouration, that exploit perceptual grouping mechanisms. Adjacent high contrast colours create false edges, but this is not sufficient for an object’s shape to be broken up; some colours must blend with the background. We test the novel hypothesis that this will be particularly effective when the colour patches on the animal appear to belong to, not merely different background colours, but different background objects. We used computer-based experiments where human participants had to find cryptic targets on artificial backgrounds. Creating what appeared to be bi-coloured foreground objects on bi-coloured backgrounds, we generated colour boundaries that had identical local contrast but either lay within or between (illusory) objects. As predicted, error rates for targets matching what appeared to be different background objects were higher than for targets which had otherwise identical local contrast to the background but appeared to belong to single background objects. This provides evidence for disruptive colouration interfering with higher-level feature integration in addition to previously demonstrated low-level effects involving contour detection. In addition, detection was impeded in treatments where targets were on or in close proximity to multiple background colour or tone boundaries. This is consistent with other studies which show a deleterious influence of visual ‘clutter’ or background complexity on search.
Highlights
The ubiquitous threat of predation has led to the evolution of different camouflage strategies that make an animal difficult to detect or recognize because of its similarity to the background or to irrelevant background objects [1,2,3,4,5]
Given that our brain relies on grouping mechanisms to distinguish an object from the background, we hypothesized that disruptive colouration would be especially effective when different components of the target resemble different objects within the background as opposed to otherwise identical background colours on a single background object
This could be because matching multiple background objects is better than matching one, even when the local contrasts at the target edge are identical, and is what we might expect from disruptive coloration
Summary
The ubiquitous threat of predation has led to the evolution of different camouflage strategies that make an animal difficult to detect or recognize because of its similarity to the background or to irrelevant background objects [1,2,3,4,5]. Animal or military, places strongly contrasting tones next to each other and, because the outline of an object is a potent cue to both its presence and identity, disruptive patterns at the body’s edge may be effective [12,13,14]. It is noteworthy that in Cott’s original illustrations of the role of differential blending in disruptive coloration, the different colour patches on the animals matched different foreground and background objects (Figure 1). We suggest that differential matching of colours on objects that have already been segmented by the visual system was implicit in Cott’s thinking and this would enhance the effectiveness of disruptive coloration We tested this proposition by presenting cryptic targets on structured artificial backgrounds to human participants using computer displays (Figure 2). The level of local background matching, in terms of colour contrast between the target’s edge and the adjacent background, was identical
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
