The Effects Of Visual Working Memory Contents On Attentional Selection Inhibitory Strategy

Orienting to inputs related to current goals as well as avoiding irrelevant inputs is considered to be one of the most important functions of attention. Many research suggested that contents of visual working memory can guide the allocation of attention. However, whether or not items matching working memory representations are necessarily to capture attention is still on debate. The present research exploited a serial of 7 experiments to invest the guidance of visual working memory on selective attention, with the purpose of verifying that items matching contents of working memory can be strategically avoided so that the search efficiency would be benefited. We also tested cognitive factors which affected the guidance of visual working memory on attention in order to further study the internal mechanism of such guidance effects. Participants were instructed to complete a visual search task while simultaneously maintaining several items in visual working memory. The crucial manipulation was whether or not there were search distractors matching the items currently stored in visual working memory.Experiment 1 and 2 varied the exposure duration of memory items and the number of memory-matching distractors. Under matching trials one of the items in working memory matched a distractor in Experiment 1 while all three items in working memory matched search distractors in Experiment 2. Both the two experiments showed an interaction between memory exposure time and trial types on the efficiency of visual search. The form of this interaction was consistent with automatic attentional capture when current visual input matched the contents of visual working memory if memory exposure time was short and strategic avoidance of attention to matching inputs if memory exposure time was long (i.e. memory-driven attention rejection). Such effects were more in evidence when the number of matching items was three rather than one. Thus, the guidance effects of visual working memory on selective attention consist of early fast bottom-up interference and relatively late top-down inhibition. The effects of different object working memory contents on memory-driven attention rejection were invested from Experiment 3 to Experiment 6. Experiment 3 and 4 required participants to remember a color and a shape, respectively. Three search distractors matched the memory feature on a random half of trials. The results suggested that visual search was facilitated in matching trials. According to such results, feature-overlaps are efficient in leading attention to evade items matching current contents of working memory. Experiment 5 and 6 required participants to remember an object. Matching conditions consisted of object-matching and feature-matching (color-matching for Experiment 5 and shape-matching for Experiment 6) trials. Experiment 5 found that search efficiency was higher in the object-matching and color-matching, compared with control trials. Experiment 6 suggested that the search efficiency was higher in the object-matching condition in comparison of control condition while it showed no difference between the shape-matching condition and the control condition. Thus, though distractors matching working memory inputs can be strategically avoided based on feature (color or shape) overlaps, the influence of colors on such effects was more in evidence, compared with that of shapes. Matching distractors can be inhibited by attention in the basis of color overlap (but not shape overlap), even though the contents concurrently kept in visual working memory were objects. Finally, Experiment 7 manipulated the number of matching distractors to invest the strategic guidance effects of spatial working memory on selective attention. The results showed search efficiency was higher in the matching trials than in the control trials when there were 2 distractors in search array matched the locations of working memory items. However, no significant difference appeared between matching trials and control trials when the number of matching distractors was comparatively lower (1) or higher (4). Such finding is considered to be related to the expense of cognition control resources caused by additional special working memory task.Sum, the present research provided further evidence that attention can be strategically evaded from items matching working memory contents while at the same time disclosing the internal mechanism of the guidance effect of working memory on attentional selection. Such guidance effects were varied by the exposure time of working memory item. When there was enough time for cognitive control to be implemented, the memory-driven rejection effect could be observed. Furthermore, this top-down process expended cognitive control resources. Only when cognitive control resources were not occupied, could the increasing of matching items give rise to bigger inhibitory effect. Finally, memory-driven rejection can also be elicited by feature over laps between search distractors and memory items and the effects of colors were more in evidence than shapes.