Abstract
Holes are perceptually organized as a background region, but people can perceive the shapes of holes as well as other figural regions. Reflecting this paradox of holes in figure/ground organization, recently there has been an ongoing controversy on whether and under what conditions holes can own shape. The current study investigated whether the global shape representation of a closed region is reversed when it changes from an object to a hole, in a more direct manner than previous studies did, using the so-called Bouba/Kiki phenomenon, a well-known example of sound symbolism. We presented observers with two ring-like cardboard cutouts having the identical circular outer contour but differing in the shape of the inner contour—one with a flower-shaped hole in it, and the other with a star-shaped hole, and observers matched them with two nonsense words, Bouba/Kiki. Since the sign of contour curvature is defined relative to a material figural side, sharp concavities and rounded bulges in, for example, a flower-shaped object turn into sharp convexities and rounded indentations in an object with a flower-shaped hole. In Experiments 1, however, we found that shape-name matching for holed objects is based on their interior shapes, but not those of materially defined inner edges. Experiments 2–3 replicated the same results even when the shapes appeared like faces of animal characters such that the material outlines of holes had ecological meanings (e.g., teeth or lips). Finally, Experiment 4 showed that shape-name matching for “C”-shaped stimuli also can be interior shape-based if the opening of the interior region is relatively small. These findings suggest that the interior shapes of holes (or negative parts in general) are automatically accessible, default, global representations of holed objects, supporting the idea that the shapes of holes are encoded as integral parts of their host objects.