From natural to sexual selection: Revealing a hidden preference for camouflage patterns

Background-matching visual patterns are selected to minimize detection by predators. However, once detected, what effects do these patterns have on conspecific perception? In humans, considerable evidence supports a "processing bias" by which people prefer images that match the spatial statistics of natural scenes, likely because the brain has evolved, or develops, to process such scenes efficiently. A direct but untested prediction of this bias is that people should prefer background-matching patterns compared to similar patterns that mismatch the spatial statistics of their surroundings. We conducted an online experiment to test this prediction on over 1,700 participants. Our results show that a preference for the most frequent value of Fourier slope (a measure of spatial structure) observed in natural scenes can be modulated by an additional preference for background-matching. Because the initial stages of perception that underlie the efficient processing of visual scenes are widely conserved among animals, especially vertebrates, we expect this preference for background-matching patterns to be shared by other organisms. Two overlooked potential implications are that some animals may choose display sites with spatial statistics matching their own phenotype, and that the evolution of visual signals will, variously, be constrained or facilitated by such preferences for background-matching patterns. Highlights- "Processing bias" has been proposed to explain the origins of preferences for sexual signals and aversion to aposematic signals - It predicts that the visual properties of background-matching patterns make them attractive - An online experiment with over 1,700 human participants confirms that prediction - Results have important implications for the preference and design of animal signals