Abstract
Two static surfaces need stratification indexes to be perceived as overlapped and plausible colors combination to be perceived as transparent. Motion leads to perceive transparency also when colors are implausible. However, the static presentation of the same stimulus will be perceived as two non-transparent overlapped figures because of the presence of stratification indexes (Hupé and Rubin, 2000). In this study we show a pattern where, in static presentation, no indexes of stratification are presented resulting in a perception of coplanar non-transparent areas both when colors combination is implausible or plausible with transparency perception. Nevertheless, the introduction of motion still leads to a perception of stratification and transparency in both cases. Stimuli consist in two movies with a horizontal rectangle composed by three vertical rectangles changing their widths during time. The two movies (plausible or implausible transparency) differ each others only because of the greyscale colors filling the vertical rectangles. In the plausible condition, colors combination was plausible with the interpretation of the pattern as two squares in which one square is transparent and slowly covers and discovers a second square. In the implausible condition, colors combination was absolutely implausible for this kind of perceptual interpretation. Ten participants observed a randomised series of the frames composing the two movies conditions in static presentation. All participants spontaneously reported, for all frames, to perceive three vertical rectangles composing an horizontal rectangle: no transparency or stratification were perceived, also when colors combination was plausible with transparency. After that, the same subjects observed the two movies and for all of them transparency and stratification was immediately perceived also when colors combination was implausible with transparency. These results show how transparency and stratification is perceived in a dynamic stimulus also if stratification indexes and plausible colors combination are not present.