Previous research has shown that stimuli held in working memory can guide spatial allocation of attention, even when the stimuli are irrelevant to a subsequent search task. Responses are speeded when the content in working memory matches a target, and are slowed when the content matches a distractor (Downing, 2000; Soto, Heinke, Humphreys, & Blanco, 2005). The relevant literature reflects on whether or not this top-down process of attentional capture from working memory is an automatic mechanism where attention gets deployed without a need for voluntary effort, and on the neural process of this endogenous control working in conjunction with bottom-up exogenous factor. So far there have not been any explorations into how the working memory might influence non-spatial selection of attentional selection, whilst also testing for the automaticity of working memory. Using Navon stimuli, I explored if and how various types of items held in working memory affect the perception of visual targets non-spatially, at local and global levels in compound letters. The data show that information in working memory biases the selection of hierarchical forms whilst priming does not, that irrelevant part of memory item also influences attentional selection, that the specific type of attentional mode (distributed vs. focused) plays an important role in selection, and that it is not easy to eradicate the top-down working memory effect.EThOS - Electronic Theses Online ServiceGBUnited Kingdo