Goodness of Dot Patterns and Completion Variability: Effects of Equidistance and Collinearity of Dots

Visual patterns that are initially poorly specified can be perceptually completed into different Gestalten (eg dot patterns can impose the perception of different figures). In the present study the following hypothesis is evaluated. If the goodness of initial patterns is high enough (high Prägnanz), then the completion of initial patterns will result in a single Gestalt (high stability of percept). On the other hand, if the goodness is low (low Prägnanz), the completion will result in several Gestalten (perceptual multistability). In experiment 1 subjects estimated the goodness of four sets of initial 8-dot patterns. The distance between the dots was systematically varied. In experiment 2 the variability of completion of the same initial stimuli was examined. Subjects were asked to choose from a given set of figures the one that was most strongly suggested by the exposed initial dot pattern. The entropy, as a measure of the completion variability, was derived from the proportions of the choices of figures. The correlation between goodness estimates (Prägnanz level) and entropy (completion multistability) was significant: the higher the goodness, the lower the multistability of initial pattern completion. The arrangement of dots was an important stimulus constraint of the dependent variables. Increasing the number of equidistant extents between dots increased multistability and decreased goodness. Collinearity of dots induced a decrease of multistability and an increase of goodness.