Logic and phenomenology of incompleteness in illusory figures: New cases and hypotheses

Cognitive and gestalt vision theories consider incompleteness to be a necessary and sufficient factor for inducing illusory figures. The role of incompleteness is studied herein by defining the inner logic subtended by use of the term "incompleteness", presenting new cases to clarify the phe­ nomenology of incompleteness as a necessary and sufficient condition, and suggesting an alternative hypothesis to explain i llusory figures after analyzing problems with the incompleteness hypothesis. 11 is demonstrat­ ed that incompleteness is not a sufficient condition, illusory figures do not necessarily complete incompletenesses, the shape of incompleteness does not predict the shape of illusory figures, and incompleteness is not a nec­ essary condition. Finally, it is noted that the incompleteness hypothesis can be replaced by concepts concerning interacting boundary grouping and surface filling-in processes during figure-ground segregation. The suggested hypothesis is consistent with neurophysiological experiments and is described in terms of the FACADE neural model of boundary and surface formation during figure-ground segregation.