The Influence Of Visual Search Template On The Guidance Of Attention From Working Memory

The interaction between working memory (WM) and attention has always been the hot topic in psychological research. In recent years, the effect of guidance of attention from WM has clarified the mechanism of the interaction between these cognitive processes in some degree, in that it revealed how and why the guidance occurred. The participants usually perform a visual search task during the maintenance of the WM, which paradigm is often used in the investigation of the guidance by WM. There are three match conditions according to the relationship between the memory content and the search target:in the target match condition, the memory item matched the search target in space; in the distractor match condition, the memory matched the distractor in the search display; in the neutral condition, the memory item didn’t appeared in the search display. Previous studies concerned about whether this guidance was automatic or under control, or what restricts the guidance, such as search goal, strategies, articular suppression and attentional control. But in the latest studies, some researchers pointed out that the state of the search template was critical in the guidance of attention from WM. In one of these studies, the experimenter instructed participants to remember two search targets and then searched one of them. They found that the other memorized target didn’t guide search when appeared in the search display. Thus they argued that when two items were activated concurrently in WM representation which would compete for the focus of attention. As a result, the effect of guidance was diminished or reduced. However, whether the focus of attention was limited to one item was controversial. Some research suggested that the focus of attention was more than one, as that they found when searched for two distinctive items there was no cost of attention-shift. In addition, in the theory of WM proposed by Baddeley (2003), the subsystems of visual working memory and spatial working memory was the most developed parts, so that we have gained an understanding of their mechanisms. As far as we know, visual WM and spatial WM were two subsystems that were rather different in encoding, representation and storing, as well as the role they playing in visual search. Therefore, we assume that the guidance of attention from WM content can be affected not only by the search template but also by the template mapping. We predict that if the effect of WM on visual attention is affected by the search template that an interaction between match condition and search template will be observed. In the other hand, if the template mapping influences the effect of guidance that there will be an interaction between match conditon and template mapping.In the current study, we applied a three-factor (search template:visual template, verbal template; template mapping:constant, varied; match condition:target match condition, distractor match condition, neutral condition) mixed design. Combined with eye movement technology, we recorded tracks of eye movement and the manual response during the visual search. According to the processes of visual search, we divided the tracks into three stages, that is, search initiation stage, scanning stage and verification stage. We also analyzed total trial duration and total fixation count. We applied repeated measurement ANOVA to analyze all these data. The results of the manual response indicated that the guidance effect was influenced by the search template. Regardless of whether the template was constant or varied across trials, the guidance of attention from WM remained under verbal template condition. However, the guidance of attention from WM was diminished for visual template both in constant mapping and varied mapping. Some novel findings were revealed in the analysis of eye movement data. In analysis of total trial duration, the effect of guidance remained when the verbal template kept constant. Furthermore, the memory item exerted an influence on total trial duration in varied mapping under visual template and verbal template, but the trend was rather different from the effect of memory guidance. The results of total fixation count suggested that search template affected the effect of guidance. Under verbal template, the number of fixation for target match conditon was less than that for neutral condition and that for distractor match condition was more than that for neutral condition. Nevertheless under visual template, total fixation count was not influenced by WM content. The search initiation stage was not affected by search template, template mapping or match condition. The second stage of visual search, the scanning process, was obviously influence by the match between the search target and the WM content in all experimental conditions except the constant visual template condition, in which we observed a shorter scanning time for target match condition and a longer scanning time for distractor match condition. The index of eye movement concerning the verification revealed a significant interaction between template mapping and match condition. When the search template was constant, the memory item had no influence on the process of verification in both search templates. When the search template varied across trials, no matter under visual template or under verbal template, the recurrence of the WM content prolonged the verification time.The results above suggested that the guidance of attention from WM was affected both by the search template and the template mapping. During the process of visual search, search template and template have an impact on this effect at separate stage. While search template affected the effect of guidance at the scanning stage, the template mapping affected the effect at process of verification. We conclude that the more specificity of the target, the less influence can WM has on search. That is the reason why visual search is more affected by WM under verbal template than visual template during scanning. Moreover, template mapping affects the verification process because activation of the template representation was competing resource for response with the WM representation. We conjecture that the focus of attention is limited to one item only if the stimulus belongs to the same subsystem in WM, but once they were represented under distinct WM type they would not compete for the focus of attention.