Illusion and illusoriness in perceptual and cognitive development

Within modern vision science, the visual illusions reveal two issues that challenge scientists. The first issue is related to the mismatch/disagreement between the geometrical/physical domain and the phenomenal one. The necessary condition for the perception of a phenomenon as an illusion, is the perception of this mismatch. The second issue follows from the first one and is related to at least two different visual levels emerging from each illusion: the perception of the illusion and the perception of the illusoriness. While the illusion is necessarily related to the presence and the perception of a mismatch between physical and phenomenal domains, the illusoriness is a perceptual attribute that is not necessarily related to the presence of a mismatch, but it can be perceived by itself and it is usually related to a sense of strangeness, singularity, quirk and oddity. Aim of this work is to study the perception of illusion vs. illusoriness. Differently from what recent neuroscience has stated we demonstrated, through some new phenomena here reported and studied in the entire life span development, that not all the illusions show the illusoriness and vice versa. Furthermore, not all the effects showing the illusoriness attribute are really illusions.