The Biology and Psychology of Visual Accentuation in Living Organisms: Toward a Comparative Phenomenology of Visual Appearance

We investigated the biological and evolutionary significance of shape- and color-based traits—signals, elements, and markings—and asked what functions they serve across animals and plants. Within a framework grounded in perceptual organization, we combine experimental phenomenology with comparative analyses to examine how specific morphological and chromatic features (e.g., appendages, horns, elongated tails, spots, stripes, and other patterns) structure visual appearance and support recognition, communication, camouflage, and sexual signaling. The results support the principle of accentuation as a plausible perceptual mechanism that can be exploited by both natural and sexual selection, helping to explain why conspicuous traits cluster in particular body regions and why similar organizational solutions recur across species. Overall, the study clarifies the biological and psychological roles of shape and color in the evolution of visual appearance.