Control of memory-guided attention

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In recent work we found that visual search is faster in repeated relative to random letter search arrays, with this contextual facilitation of behavioral reaction times being accompanied by, and correlating with, enhanced lateralized ERP responses peaking already 80 - 180 milliseconds post-stimulus onset (N1pc component and followed by the lateralized N2pc and CDA, starting at around 200 and 400 ms, respectively) over parieto-occipital electrode sites. These findings confirm existing statistical-learning accounts according to which re-occurring search patterns lead to more effective attentional allocation towards potential target items (reflected by the N2pc). However, our new findings also suggest an extension of these accounts such that statistical-learning experiences increase the attentional priory of potential target items (N1pc), critically, even before voluntary attentional allocation (N2pc), while also exerting an influence on how much (target/ distractor) information is represented in search-guiding working memory (CDA). In the proposed project, we will use visual search and investigate the sensory-cognitive mechanisms underlying (the in repeated arrays more effective) N1pc and CDA using behavioral reaction times in combination with temporally-precise EEG, including also EEG-informed functional MRI. We suspect that the temporally-early N1pc marks experience-dependent changes of spatial maps encoded in circuits contributing to long-term memory of target-context relations and/ or visually guided spatial attention and instantiating a bias for voluntary target selection (N2pc) and eventual attentional suppression (PD), the latter after a target location change (from one hemifield to the other) in a learned contextual array and if the initial attention-orienting process was not capable to detect the task-relevant target item. Concerning the CDA: we will test the novel idea that attentional orienting from learned search arrays is as effective as that with visible arrow cues and thus elicit CDAs during lateralized visual search. Moreover, we ask whether CDAs reflect obligatory working-memory encoding and whether the enhanced CDA in learned search arrays marks enhanced working memory for distractor and/ or target items.