Visual illusions constitute an interesting perceptual phenomenon, but they also
have an aesthetic and affective dimension. We hypothesized that the illusive
nature itself causes the increased aesthetic and affective valence of illusions
compared with their non-illusory counterparts. We created pairs of stimuli. One
qualified as a standard visual illusion whereas the other one did not, although
they were matched in as many perceptual dimensions as possible. The phenomenal
quality of being an illusion had significant effects on “Aesthetic Experience”
(fascinating, irresistible, exceptional, etc), “Evaluation” (pleasant, cheerful,
clear, bright, etc), “Arousal” (interesting, imaginative, complex, diverse,
etc), and “Regularity” (balanced, coherent, clear, realistic, etc). A subsequent
multiple regression analysis suggested that Arousal was a better predictor of
Aesthetic Experience than Evaluation. The findings of this study demonstrate
that illusion is a phenomenal quality of the percept which has measurable
aesthetic and affective valence.