Guidance of visual attention from working memory contents depends on stimulus attributes.

Recent work shows that items maintained in working memory could guide the orienting of attention in visual search, demonstrating an interesting interaction between working memory and attention. For such guidance effect, some studies emphasize the importance of search task type: for fixed-target search, task-irrelevant memory items stay inside the attentional focus and guides attention; for varied-target search, these items stay outside attentional focus and do not guide attention. With two experiments, we showed that stimulus attribute of items held in working memory can play an important role in attentional guidance. The first behavioral experiment duplicated a previous fixed-target search paradigm demonstrating robust guidance effect but failed to find such effect when the stimuli was simply changed from colored shapes to complex artificial shapes. The second event-related potential experiment duplicated a previous varied-target search paradigm that used complex shapes but did not observe any guidance effect. A clear guidance effect was found when we changed the stimuli to colored shapes. The results suggest that attentional guidance from working memory depends on stimulus attributes of the items held in working memory. When effective attribute is used, task-irrelevant items that stay outside the attentional focus are still able to guide attention.