Abstract
Preference for visual symmetry (unity ratio, 1:1) over other proportions is documented using area relationships in divided, two-dimensional black-and-white shapes (Davis & Jahnke, 1991) and, despite the presence of a simultaneous color contrast, in divided two-dimensional colored shapes (Davis, 2007). The present experiments sought to determine visual preferences for an illusion produced by a three-dimensional stimulus. Participants viewed six height-to-width ratios for each of six shapes, varying in dimension (2- or 3-D), illusion and symmetry. Shapes included a nonsymmetrical shape, Necker cube, Necker cube with an alteration, two-dimensional Necker cube, bi-stable diamond illusion, and a cylinder. Experiment 1 utilized a stimulus booklet, where ratios of a shape including unity and the golden section (1:1.618) were presented on each page. The six shapes were represented several times within the booklet. Participants indicated which ratio of a shape they found to be most aesthetically pleasing. Experiment 2 utilized a booklet, consisting of all shapes and ratios used in Experiment 1. A 5-point Likert-type scale assessed aesthetic preference for each shape × ratio stimulus presented singly on a page. Analysis of Experiment1 revealed a preference for the unity ratio for all but one shape (cylinder), even when an illusion was present, X2 (25) = 188.116, p [[lt]].05. Despite its historical significance, there was no preference for the golden section (1:1.618) in any shape. Results for Experiment 2 were mixed; the unity ratio was preferred in the Necker cube illusion, but not in weaker versions. These results have two implications: processing of illusions may be easier when unity (and, often, symmetry) is present; and, methods used to assess preference differences using more complex three-dimensional shapes are impacted diversely by the availability of information to make comparisons. Relative judgment procedures provide more information, including the range of possibilities, than absolute judgment procedures.