In the present study, we used Navon-type Cognitive Psychology 9: 353-383 (1977) hierarchical patterns to demonstrate that cognitive load eliminates a global perceptual bias and enhances the representation of local elements at unlimited exposure durations. We added a cognitive-load manipulation to Kimchi and Palmer's Journal of Experimental Psychology: Human Perception and Performance 8: 521-535 (1982) similarity-matching experiment with hierarchical patterns, and presented the stimuli for either unlimited or limited exposure durations. When exposures were unlimited, we demonstrated that observers exhibited a global bias under low, but not under high, cognitive load (Exp. 2). When exposures were limited, however, cognitive load exerted no effect, and the global bias remained (Exp. 1). We suggest that (1) these findings are best reconciled by proposing two stages in the representation of global structure, namely construction and maintenance; (2) the construction and maintenance stages are isolated, respectively, by limited-duration and unlimitedduration paradigms; and (3) cognitive processes play an integral role only in the maintenance stage. Given that real-world vision is not driven by a series of brief stimulus exposures, and is therefore likely to reflect maintenance processes, we argue that unlimited-exposure paradigms are more suitable for addressing real-world perceptual biases. When unlimitedexposure paradigms are used, cognitive load eliminates the commonly reported global bias.Keywords Navon stimuli . Cognitive load . Global-local . Perceptual biasThe visual world is inherently hierarchical (Navon, 1977;Palmer, 1975); to use a common analogy, the forest exists as a global configuration of individual trees. In the Western world, there is a well-cited "global precedence" (Navon, 1977; see Kimchi, 1992, for a review), in that the analysis of visual information is initially dominated by the processing of global structure. This has been explained in terms of how the brain processes spatial-frequency information; lower spatial frequencies, which carry more global-level information, are processed faster than the higher spatial frequencies, which define more local detail (e.g., Shulman, Sullivan, Gish, & Sakoda, 1986). The processing precedence of global information has, however, been demonstrated when stimulus presentation time is restricted, and this would not necessarily translate into a global bias in situations in which stimulus presentation time is unrestricted (arguably more akin to real-world viewing conditions). In the present study, we argue that for the global form to be most "salient in the final percept" (Kimchi, 1992, p. 26), the initial dominance of global structure must be maintained by cognitive processes; imposing a load on cognitive resources weakens the structural cohesiveness of the global form and increases the relative strength of local information. As the world is full of cognitive distractions, this has fundamental implications for the way in which visual information is repr...

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