Does Spatial Orientation Information Of Working Memory Deploy Selective Attention In The Visual Search

There is a lot of evidence that working memory can automatically or strategically deploy selective attention in the visual search (Soto, Heinke, Humphreys,& Blanco,2005; Soto, Hodsoll, Rotshtein & Humphreys,2008; Olivers,2009). Usually the contents of visual working memory are represented in terms of color, shape or object. However, there are few studies which concern spatial orientation information. Considering the functional dissociation between visual-object and visual-spatial information processing in the visuo-spatial sketchpad, we investigated the deployment of spatial orientation to selective attention.Experiment 1 asked subjects to remember the orientation of one arrow, then search the target and complete a memory task. The search reaction time suggested that the orientation kept in working memory can capture attention in some degree, but the effect was not significant, due to limited by the experimental design.Experiment 2 used three arrows from an origin which divided the plane into three 120°segments to indicate the orientation. Participants were told to memorize either one of three orientations or the color, then completed a search task and memory task.Experiment 3 used the same stimuli and procedure, except for the change of angles among different orientations which were non-centrosymmetric.Both the experiments, regardless of whether they utilised regular orientation (Exp 1) or irregular orientation (Exp 2), showed that when orientation was held in working memory, both the orientation-matched and color-matched items could automatically capture attention strongly. However, when color was kept in working memory, the orientation-matched item didn’t affect the search task, while the color-matched item still captured attention robustly.These results suggest that color in the working memory undoubtedly deploys attention by capturing it automatically, but orientation in working memory may lead to a weaker effect. It appears that maintaining orientation information in the visuo-spaital sketchpad is a controlled process.