Abstract
Reversible (or unstable) figures such as Rubin’s faces-vase (Rubin, 1915/1958) have long been used to probe and increase our understanding of underlying processes related to perceptual organization. Typically the faces-vase stimulus consists of a single central vase and an inward looking face on either side of the center that perfectly abuts the vase so that they share a common border. The reversibility of this stimulus is due to an ambiguous figure-ground organization. When the vase is perceived as the figure (i.e., when the central region is been interpreted as a vase) the faces are perceived as the ground, and vice versa. This results in a perception of either the faces or the vase approximately half of the time. The watercolor illusion (WCI) has been shown to increase the likelihood of a region being perceive as figure – even when that conflicts with various Gestalt cues for figure-ground organization (Pinna et al., 2001). The WCI occurs when a physically non-colored region surrounded by an outer contour and an inner fringe of contrasting hue appears filled in with a pale tint the same hue as the fringe. To test whether the WCI could selectively bias perceptions of the faces or the vase as figure, faces-vase stimuli were created in which the WCI inducing fringe was either in the faces, the vase, or did not exist. We found that participants saw the region containing the WCI as figure more often than the region without regardless of whether the WCI containing region was the faces or the vase, and participants saw the faces and vase approximately equally when no WCI was present. This experiment supports previous work suggesting the WCI has a strong figural component and is the first to incorporate the WCI into reversible figures.