Abstract
Many theories of visual attention propose that working memory and perception interact during the processing of complex scenes (e.g., Desimone and Duncan, 1995). In addition, previous research with monkeys has suggested that target objects are preferentially processed during visual search because template representations in working memory bias perceptual mechanisms in a top-down manner. Does the human visual system also automatically allocate attention to objects that match the contents of visual working memory? We addressed this question in a series of experiments using a dual-task paradigm. Subjects were required to store an object representation in visual working memory and then perform a visual search task while maintaining this representation. Both behavioral and ERP data indicated that the contents of visual working memory did not lead to the automatic orientation of attention toward similar items. Contrary to several theories of attention, these findings demonstrate that holding an object representation in visual working memory is not sufficient to ensure that attention automatically selects similar objects. These findings also suggest that the visual system may use perceptual attention mechanisms to temporarily maintain representations of objects after such attention mechanisms are freed from the demands of the visual search task. Thus perceptual attention may also aid in the maintenance of object representations in a manner that is similar to the way in which attention has been demonstrated to aid in spatial working memory tasks.
Supported by grant 1 F31 MH12995-01 and MH63001 from NIMH and grant SBR 98-09126 from NSF.