Abstract
The abstraction of 3D scene structure from 2D image information—e.g., representing the relative depths of surfaces, the continuation of occluded surfaces behind other surfaces, the grouping of discontinuous contrast regions as reflecting a single object in the world, etc.—is a critical pre-categorical component of establishing internal representations of the external world that guide successful action; i.e., the general function of vision. Much of what we know about these perceptual organization processes, however, has been learned from experiments that present stimuli at or near fixation. The quality of image-level representations, on which mid-level processes depend, declines sharply from central to peripheral regions of the visual field due to decreased acuity, and more critically, to the spatial uncertainty that leads to visual crowding. This raises the possibility that perceptual organization processes do not function in peripheral vision in the same way that they function in central vision. Using the configural-superiority effect as a metric, we measured multiple perceptual organization processes, including closure, surface completion, 3D structure from 2D geometry, and surface scission from transparency, for stimuli presented at fixation versus 15° to 24° in the periphery, controlling for cortical magnification. We found substantial differences for most of these organization processes, consistent with the possibility that the periphery is perceptually unorganized; it may be represented in terms of non-unitized segmented textures, rather than perceptual units (a.k.a, objects). Downstream processing consequences of this possibility, including failures of object correspondence and object-mediated representational updating, are discussed.