Understanding human cognition requires the characterisation of the limitations that our processing capacities are subject to. Such questions have been central to the examination of two key constructs in cognitive psychology: Working Memory (WM) and attention. In the domain of WM, recent models have posited a focus of attention, analogous to selective attention in perception, in which a single item is prioritised over others for cognitive operations. In nine experiments, this thesis explores the nature of the focus of attention in spatial WM in two regards. First, I used eye movements and reaction times to examine how priority is allocated to internal representations (Experiments 1-4). The results of these experiments indicated that orienting in WM could be decomposed into processes analogous to perceptual attention orienting. Through this, I was able to characterise three contributions to the switch cost: a) a process of cue evaluation; b) the process of orienting between objects; and c) interference between locations arising from attention shifts. Subsequently, I observed neurophysiological correlates of the first and third of these contributions in event-related potentials (Experiment 5). Second, building upon an increasing amount of evidence indicating an overlap between perception and WM, I sought to examine whether analogous processes of selection in both domains reflect a common mechanism (Experiments 6-9). Specifically, I examined whether the selection of an object in spatial WM was dependent on mechanisms underlying perceptual processing. The findings from these experiments indicated that selection in WM interacts with perceptual attention shifts, but is not dependent upon them. Overall, this thesis provides an account of how selection in WM is related to perceptual attention, and critically, how they are distinct. I account for these findings in a framework which specifies distinct representations for perception and WM, but in which they interact through a shared representation of attentional priority.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:627966 |
| Date | January 2013 |
| Creators | Hedge, Craig |
| Publisher | University of Bristol |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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