Investigating metrical and structural aspects of visual completion: priming versus searching

Abstract

Earlier research on visual occlusion showed some flexibility in the formation of visual completions, as long as the structural aspects (e.g., symmetry) of the visible part of the partly occluded shape were preserved in the completion (de Wit & van Lier, 2002). In this study, we examined whether changing the overall size of the occluded shape would preserve the overall structure. In Experiment 1, using the primed-matching paradigm, we found evidence for relative size invariance in the completion process. To investigate whether changes in the structural aspects of shape are generally more salient than those of size, we employed the same stimuli in visual search and change detection paradigms. Experiment 2 demonstrated effects of completion in both paradigms. Experiment 3 showed that the metrical aspects of the shapes used in Experiment 1 are nevertheless detected faster than the structural aspects under search conditions. Because the variation in structural aspects is not more salient than in metrical aspects, we conclude that for these shapes, visual completion is indeed size-invariant. The relations between performances in the three paradigms are discussed.