Using composite fractal patterns to investigate the aesthetic perception of nature's scenery

Fractal patterns are abundant in natural environments, appearing in clouds, mountains, trees, and other objects. Characterized by self-repeating structure, these patterns vary in visual complexity, which can shape aesthetic perception. We conducted a scoping review of the literature on the fractal properties of natural objects to estimate typical levels of fractal complexity. Using fractal dimension ( D ) as a measure, we found that natural objects tended to exhibit moderate rather than extreme complexity. Building on this review, we used computer-generated “composite fractal” stimuli to investigate how observers perceive layered fractal structures. In a behavioral within-subjects study, we examined the relationships between fractal type, fractal dimension, and visual appeal. We created two types of fractals to mimic common natural forms: “contour” and “cluster” fractals. Study blocks included single-layer fractals, composite fractals with contour and cluster layers of the same D value, composite fractals with differing D values across layers, and a mix of single and composite fractals. Results showed that visual appeal for contour fractals peaked at D = 1.1, while cluster fractals were preferred at D = 1.5–1.7. For composite fractals with equal D values, peak appeal occurred at D = 1.1–1.5, whereas for multi- D composites, visual preference was greatest when the contour layer was of lower complexity than the cluster layer. These findings support fractal fluency theory, suggesting that aesthetic responses are influenced by the prevalence and relational structure of fractal patterns in natural environments.