Abstract
Perceptual interference can occur when observers discriminate a target among similar distractors. Recognition performance is poorer for subtle visual discriminations, suggesting that targets and distractors activate overlapping representations and thereby lead to capacity-limited processing. Previous studies have shown that the processing of different expert categories likely depends on shared processing resources (Gauthier et. al, 2003) even with visually distinct expert categories (e.g., faces and cars processed by car experts). Here, we examined whether the temporal limits of visual recognition might be altered by expertise with a particular object category, with greater interference occurring between object categories that depend on similar expertise processing strategies and thus common resources.
Car experts and novices viewed rapid serial visual presentations (RSVP) of heterogeneous images that required the identification of either: face targets presented among alternating images of face and car distractors or face and watch distractors, watch targets among watch and face distractors, or watch and car distractors. An adaptive staircase procedure was used to determine temporal thresholds for recognition. Car experts required slower presentation rates than novices to identify a face amongst irrelevant cars. The poorer performance of car experts could not be attributed to the capture of attention by objects of expertise, because they could identify a watch amongst irrelevant cars at faster rates than novices. In fact, the speed of face identification amongst car distractors was positively correlated with a quantitative measure of car expertise, whereas car expertise was negatively correlated with watch identification amongst car distractors. In control conditions where neither targets nor distractors were cars, the degree of car expertise was irrelevant. These results may reflect a multidimensional representation of object similarity in cortex that extends beyond simple measures of visual similarity. Expertise with an object category may alter the functional distance between object representations within this multidimensional space.
This work was supported by a grant to the Perceptual Expertise Network from the James S. McDonnell Foundation