ABSTRACT
This chapter summarizes a growing body of literature on organizational effects in vision. Although they are readily experienced phenomenally, these effects also surface in the performance of information-processing tasks requiring selective attention, discrimination, or search. Primary emphasis is given to perceptual grouping and to how it can be measured, what causes it, and what its consequences may be. Following concepts proposed by Gamer and by Kahneman, grouping of parts into unitary shapes or configurations is operationally defined as a failure of selective attention to individual parts. Using selective attention measures, it is possible to demonstrate objectively the role of various stimulus factors, such as element proximity and similarity, in causing grouping to occur. A major consequence of grouping is the creation of emergent features via interaction of parts in the perceptual process. Emergent features are not identified by prior recognition of parts but instead are recognized directly. Nor is the speed of their recognition predictable from the speed of recognizing their constituent parts: Wholes may be recognized either more quickly or slowly than their parts. Configural superiority effects, wherein wholes are perceived faster than their component parts presented in isolation, arise from the direct recognition of the emergent features of these wholes. Similarly, configural inferiority effects arise when the whole’s emergent features are recognized more slowly than its constituent parts. Two types of configuration may be distinguished—one that depends primarily on just the location of the component parts, and one that depends as well on the identity of those parts. The relationship between perception of parts and wholes is different for these two types of configuration, which may help resolve 142some otherwise curious discrepancies in the literature. Placing a part within a whole may create (in addition to emergent features) masking effects on that part, destruction of the part’s features, or other changes in the part’s appearance (e.g., its perceived orientation), all of which may impede the perception of the part but leave perception of the whole unimpaired.
