Spatial Specificity Of Feature-Based Interaction Between Working Memory And Visual Processing

Visual working memory interacts with ongoing visual processing in a stimulus-specific manner, potentially through a common neural substrate supporting visual perception and working memory maintenance. The spatial specificity of this effect, however, remains unknown. The current study tested whether features in working memory influence perception in a spatially specific or global fashion. Across four experiments, subjects performed perceptual discrimination tasks on orientation or on contrast while concurrently holding an orientation in working memory. Experiments 1 and 2 revealed that memory content boosted the perceived contrast of the discrimination stimulus when the two matched in orientation, but only when the locations of the memorandum and the discriminandum also matched. In turn, feature-based influence on memory precision was also greater when locations matched. Experiments 3 and 4 demonstrated that the spatial specificity of this interaction was influenced by task demands. When encoding of location was discouraged in Experiment 3, memory interacted with perception in a global fashion, whereas when location was task-relevant in otherwise very similar Experiment 4, the feature-based enhancement was again modulated by location. These results suggest that context-binding demand is an important determinant of the spatial specificity of memory-perception interaction and highlight the flexible configurability of working memory representations.