An Exploration of the Role of Temporal Information in Hierarchical Working Memory Representations and their Influences on Visual Attention

This thesis investigates how visual working memory effects may differ at different levels of a hierarchically structured system. Traditional visual working memory research has focussed on memory for exact features of individual objects. However, working memory can also include other types of information, such as the ‘average’ feature value across a group of stimuli, or the relative spatial relationships between stimuli. Most studies have used static displays of stimuli presented simultaneously, so this thesis aimed to investigate whether similar mechanisms could operate across stimuli presented sequentially, though this thesis failed to replicate previous results even when presenting simultaneous stimuli. It also investigated whether group level representations are observed using tactile stimuli, based on evidence of integration across tactile inputs, but fails to replicate these effects.
A second research topic was that of memory guided attention. Holding an item in memory can bias the allocation of attention in favour of new incoming information that shares similar features. However, it remained unclear how the degree of similarity between the new items and memory item modulated such guidance. This thesis attempted to replicate such guidance effects using orientation as the critical feature, to allow similarity to be quantified better. However, no memory guidance effects were observed under these conditions. Finally, so far previous studies had also primarily used static arrays of simultaneous stimuli, so this thesis investigated whether such guidance effects could affect the allocation of temporal attention, though again no such evidence was observed.
The thesis furthers our understanding of the limits of the interplay between attention and memory across time, by failing to find evidence of previously established mechanisms under new conditions, including novel feature dimensions, sequential presentation, and tactile stimuli and thus questioning the generalisability of the previous research in this area.