Abstract
Studies of facial perception have shown that observers' performance identifying facial parts (e.g., nose from face A) is better when that part is present in the context of the correct source face rather than a different source face. Studies of the perception of hierarchical forms have shown that observers' performance identifying local elements is better when those elements are combined to form a global pattern that is consistent rather than inconsistent (e.g., small Hs combined to form a large S). We describe here a first experiment designed to test the general hypothesis that effects in facial perception and effects in object perception reflect the same characteristics of visual perception. There are two specific hypotheses that are addressed in this work: (a) Perceptual organization relies as much or more on similarity at the level of second-order characteristics than at the level of first-order physical characteristics, and (b) perceptual organization reflects both perceptual and decisional factors. The present experiment uses stimuli in which the global forms emerge as illusory contours, with these contours being either consistent or inconsistent with the local forms. Observers are presented with these stimuli and make identification responses to both the global and local forms. The design allows for both the detection of dimensional consistency effects, and inferences regarding perceptual independence, and perceptual and decisional separability. Results indicate that (a) it is possible to obtain dimensional consistency effects with illusory contours, and (b) both perceptual and decisional components are implicated in these effects.