Sequential dependences of perceptual interpretations of a repetitively illuminated reversible figure

The Necker cube pattern was illuminated by xenon flashes repetitively at different but always regular interstimulus intervals. Subjects pushed one of two buttons corresponding to the subjective perceptual interpretation of the pattern. Analysis of the resulting binary sequences showed that none of the sequences was random. The order of Markovian dependence was higher for sequences with longer (3.6 and 2.4 s) interstimulus intervals than for shorter (1.2 s) ones. This result points to the significance of perceptual sets related to short-term memory mechanism upon perception.