This study examines cross-cultural differences in aesthetic evaluation of Ikebana (Japanese flower arrangement) across four cultures: Japan, Germany, the United States, and the United Kingdom. We investigate how cultural background, symmetry perception, and individual differences influence aesthetic judgements of 75 original Ikebana works. Three hundred participants from each culture will evaluate 30 Ikebana images on multiple dimensions: beauty, liking, positive/negative emotions, mixed emotions, and arousal. We analyze both subjective (perceived) and objective symmetry using computational measures from the Aesthetics Toolbox, controlling for low-level image features such as brightness, color statistics, and complexity. We hypothesize that Japanese participants will evaluate Ikebana more favorably due to greater cultural familiarity. We predict positive linear effects of both subjective and objective symmetry on aesthetic evaluation, with a possible inverted-U relationship for subjective symmetry. Crucially, we expect interactions between culture and symmetry: the positive symmetry-aesthetics relationship should be stronger among Western participants than Japanese participants, suggesting that cultural expertise may reduce reliance on symmetry as an aesthetic cue. Individual differences in visual aesthetic sensitivity, desire for aesthetics, Ikebana experience, and attitudes toward ambiguity will be examined as moderators. At the time of abstract submission, data collection has not yet begun. However, by the time of the conference presentation, we will present comparative results from all four countries.