Novel Procedure for Generating Continuous Flash Suppression: Seurat Meets Mondrian

Abstract

Continuous flash suppression (CSF), used in hundreds of studies to manipulate visual awareness, entails presentation of a stationary image (the ‘target’) to one eye and an animated sequence of arrays of geometric figures (the ‘mask’) to the other eye. The prototypical CFS sequence comprises different-sized rectangles of various colors, dubbed ‘Mondrians’ after the Dutch painter Piet Mondrian whose abstract compositional style used simple forms and colors devoid of figurative quality. When presented as a rapid, changing sequence to one eye, Mondrians - or other, similarly constructed textured arrays - can abolish awareness of a target viewed by the other eye for many seconds at a time, producing target suppression durations much longer than those associated with conventional binocular rivalry. We have devised a novel visual animation technique that replaces meaningless Mondrian figures with recognizable visual objects and scenes as inducers of CFS, allowing explicit manipulation of the visual semantic content of those masks. By converting each image of these CFS sequences into successively presented objects or scenes each comprised of many small, circular patches of color, we can create ‘pointillist’ (cf. Seurat) CFS sequences closely matched in terms of their spatio-temporal power spectra. Moreover, randomly rearranging the positions of the pointillist patches yields scrambled versions of these images, thus destroying their recognizability. Using poin-tillist CFS sequences, we have discovered that CSF sequences comprising a stream of different objects produces more robust interocular suppression than do sequences comprising a stream of different scenes, even though the two categories of CSF are matched in low-level feature strength. Color is not critical for creating this superiority of objects over scenes, as demonstrated by CFS sequences made from achromatic object- and scene-images. Poin-tillist CFS provides a useful means for examining the impact of high-level image meaning in the modulation of visual awareness.