Investigating the Relationship Between Working Memory and Selective Attention

Abstract

Optimal performance of everyday tasks like driving depend critically on both the ability to store and retrieve small amounts of information in the short term, and the ability to selectively find and process relevant objects while preventing distraction. These two abilities have traditionally been viewed as distinct processes in human cognition, however research now demonstrates significant overlap between the constructs of working memory and selective attention. Previous work has established a role for working memory resources in the successful control of attention, however there are many processes underlying successful attentional control, and affecting any one of them would produce the pattern of results that have been observed. In this thesis we used behavioural and electroencephalographic evidence to investigate working memory and selective attention. We aim to provide a more detailed understanding of the processes underlying the relationship between these two constructs. Study 1 provided systematic documentation of the effect that distractor objects have on performance in a traditional working memory task, as well as the relationship between these effects and individual differences in working memory capacity. Study 2 used lateralized event-related potentials to measure dissociable components related to target selection, distractor capture, and distractor disengagement while working memory load was manipulated. Study 2 used electroencephalographic measures of attention processes to show that increased working memory load has a specific effect on neural indices of distractor disengagement. Study 3 used a similar paradigm to Study 2 to show that the presence of irrelevant objects during working memory encoding leads to impairments in performance and modulation of the neural response to targets in a concurrent visual search task. Together, our results provide greater specificity of the relationship between attention and working memory while demonstrating the utility of lateralized ERPs in providing dissociable measures of specific attentional sub-processes. This provides a promising tool for future research which investigates the relationship between working memory and selective attention.