How does the mind handle uncertainty in ambiguous figures?

Abstract

How does the mind select one interpretation from a bistable stimulus and how this eventually becomes conscious? We briefly presented 17 rotations of an ambiguous figure to observers and asked them to give a quick response. We were interested in determining how observer factors, stimulus properties and context influence the selected response. Data analysis revealed that observers assigned probabilistically each figure rotation to a category according to an implicit criterion of typicality or prototype. From discriminant analyses we ascertain how the standardized coefficients change as do the testing conditions, mainly when stimulus information is lacking or confusing. Results suggest that the proximity to the prototype expresses the uncertainty of the subject's response and may be gradually manipulated by the orientation of the figure. Depending on the uncertainty value, discriminant strength of the observer and contextual factors have greater influence on responses than the physical properties of the ambiguous stimulus.