More than mere association: Are some figure-ground organisation processes mediated by perceptual grouping mechanisms?

Figure-ground organisation and perceptual grouping are classic topics in Gestalt and perceptual psychology. They often appear alongside one another in introductory textbook chapters on perception and have a long history of investigation. However, they are typically discussed as separate processes of perceptual organisation with their own distinct phenomena and mechanisms. Here, I will propose that perceptual grouping and figure-ground organisation are strongly linked. In particular, perceptual grouping can provide a basis for, and may share mechanisms with, a wide range of figure-ground principles. To support this claim, I will describe a new class of figure-ground principles based on perceptual grouping between edges and demonstrate that this inter-edge grouping (IEG) is a powerful influence on figure-ground organisation. I will also draw support from our other results showing that grouping between edges and regions (i.e., edge-region grouping) can affect figure-ground organisation (Palmer & Brooks, 2008) and that contextual influences in figure-ground organisation can be gated by perceptual grouping between edges (Brooks & Driver, 2010). In addition to these modern observations, I will also argue that we can describe some classic figure-ground principles (e.g., symmetry, convexity, etc.) using perceptual grouping mechanisms. These results suggest that figure-ground organisation and perceptual grouping have more than a mere association under the umbrella topics of Gestalt psychology and perceptual organisation. Instead, perceptual grouping may provide a mechanism underlying a broad class of new and extant figure-ground principles.