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Category: Procedure

Description: Conspicuousness is a known attractive stimulus feature. For instance, a preference for conspicuous colour stimuli was shown in several species (Andresson, 1994; Waitt et al., 2003; Gomez et al., 2009; Ryan & Cummings, 2013). At the same time, efficient stimuli, that is, stimuli that are sparsely processed by environmentally tuned neurons of the visual system, are also attractive (Renoult, Bovet, and Raymond, 2016). Interestingly, background-matching camouflage falls in the efficient stimuli category as it relies on matching the stimulus features with the habitat features. They should thus be attractive to the observer despite their lack of conspicuousness. As such, our study tests whether camouflage patterns can be a pre-adaptation to socio-sexual signals in animals. In the proposed study, we want to determine whether camouflaged stimuli are, indeed, perceived as attractive. In a first experiment, we will assess the relative effectiveness of camouflage with different background-matching stimuli (we will vary the level of background matching by modifying the Fourier slope of both background and target patterns) using a detection task. In a second experiment, we will present the same stimuli but modified to make detection straightforward (higher conspicuousness than in the detection task, i.e., their contour will be made more obvious and they will be centred) and ask the observer to choose the stimulus they find more attractive in a two-alternative-forced-choice (2-AFC) design. Finally, in a third experiment, we will measure the absolute attractiveness of our stimuli by changing the background into a grey background. This third experiment will consist of the same task as in experiment 2 (2-AFC design).