Local and Global Processes in Visual Completion

Abstract

In the natural environment, objects are frequently occluded, and people continuously complete partly occluded objects Do local processes or global processes control the completion of partly occluded objects? To answer this question, most previous studies simply asked subjects to draw the completions they “saw” Such drawing tasks are highly subjective, and they provide equivocal results Our studies are the first to use an objective, implicit paradigm (primed matching) to determine the extent to which local or global processes underlie the visual completion of partly occluded objects Our results suggest that global processes dominate perceptual completion, whereas local processes do not play a large role Therefore, local theories of completion, or theories in which local processes dominate, cannot be entirely correct

When half a face is as good as a whole: Effects of simple substantial occlusion on visual and audiovisual speech perception

“…In particular, research in the domain of object recognition has shown that observers have the capacity to perceptually "complete" objects when they are only partially specified due to occlusion (e.g., Sekuler, 1994;Sekuler, Palmer, & Flynn, 1994). Moreover, this process may be facilitated by object symmetry (e.g., Vetter, Poggio, & Bülthoff, 1994;Yokota, 1994) and has been observed for the perception of faces (Nakayama, Shimojo, & Silverman, 1989; see also Braddick, 1988).…”

Adapting a memory framework (source monitoring) to the study of closure processes

“…Although the filling-in processes thought to mediate object identification are characterized as relatively automatic ones, the nature of the processes subserving completion have only recently been the focus of study (Behrmann, Zemel & Mozer, 1998;Sekuler & Palmer, 1992;Sekuler et al, 1994). Our experiments suggest that sourcemonitoring judgments may help to identify these mechanisms more precisely.…”

“…These analogues include the use of fragmentation (Biederman, 1987;Bregman, 1981;McClelland & Rumelhart, 1981;Snodgrass & Feenan, 1990) and priming tasks (Sekuler & Palmer, 1992;Sekuler et al, 1994). In fragmentation tasks, pictures of objects (e.g., Snodgrass & Feenan, 1990) or words (Snodgrass & Kinjo, 1998) are rendered incomplete by partial deletion (e.g., Snodgrass & Feenan, 1990) or partial occlusion (e.g., Bregman, 1981;Brown & Koch, 1993;McClelland & Rumelhart, 1981).…”

“…One theoretical perspective proposes that filling-in processes, often referred to as closure processes, are automatically activated by the incomplete visual information and serve to supply the "missing" portions of objects (or pictorial referents) in the mind's eye (Akins, 1996;Churchland & Ramachandran, 1996;Sekuler et al, 1994;Snodgrass & Feenan, 1990;Snodgrass & Kinjo, 1998). An alternative view suggests that the visual system essentially ignores the missing information; object recognition occurs when there is sufficient information in the incomplete form to resolve its identification(e.g., Dennett, 1992Dennett, , 1996Hearst, 1991).…”

“…The empirical study of object identification under these conditionsof incomplete visual information has a long and fruitful history (Gollin, 1962;Kanizsa & Gerbino, 1982;Leeper, 1935;Sekuler & Palmer, 1992;Sekuler, Palmer, & Flynn, 1994;Snodgrass & Feenan, 1990), yet theoretical debates about the mechanisms mediating this ability are far from resolved (e.g., Akins & Winger, 1996;Churchland & Ramachandran, 1996;Dennett, 1992;Kellman & Shipley, 1991;Kimchi, 1992;Pessoa, Thompson, & Noe, 1998;Sekuler, 1994). One theoretical perspective proposes that filling-in processes, often referred to as closure processes, are automatically activated by the incomplete visual information and serve to supply the "missing" portions of objects (or pictorial referents) in the mind's eye (Akins, 1996;Churchland & Ramachandran, 1996;Sekuler et al, 1994;Snodgrass & Feenan, 1990;Snodgrass & Kinjo, 1998).…”