Perceptual biases, camouflage patterns, and the origin of sexual signals

Natural and sexual selection can be in conflict in driving the evolution of sexual ornamentation. Sexual selection typically favors detectability to potential mates, whereas natural selection penalizes detectability to avoid predators. Considering signal efficiency in addition to detectability, however, suggests that natural and sexual selection need not be antagonistic. In the visual domain, 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 to process such scenes efficiently. A direct but untested prediction of this bias is that background-matching camouflage can be favored by natural and sexual selection. We conducted an online experiment where we show for the first time human preference for camouflaged patterning and confirm a preference for the average image statistics of natural scenes. Because many of the underlying visual mechanisms are shared across vertebrates, our results suggest that camouflage patterns can serve as evolutionary precursors of sexual signals. ### Competing Interest Statement The authors have declared no competing interest.