Dissertations, Theses, and Capstone Projects

Date of Degree

9-2019

Document Type

Dissertation

Degree Name

Ph.D.

Program

Psychology

Advisor

Robert Melara

Committee Members

Timothy Ellmore

Matthew Hoptman

Brett Silverstein

Vivien Tartter

Subject Categories

Cognitive Neuroscience | Cognitive Psychology

Keywords

Reorienting Negativity, RON, Auditory Attention, Attention, Distraction

Abstract

The three-stage model of distraction asserts that when we are presented with salient but task-irrelevant information, our sensory systems first detect the distracting stimulus by way of sensory memory buffers, which is indicated electrophysiologically by the mismatch negativity (MMN). Following detection, attentional resources are involuntarily allocated towards the processing of the distraction, as represented by the P3a. Finally, attentional resources are shifted away from the distracting stimulus and returned to the task-relevant information, as indicated by the reorienting negativity (RON). A great deal of research has focused on this last step in the model, largely centering around defining the mechanisms that modulate and produce the RON. From the previous research it has become clear that both attentional and working memory mechanisms play a role in the production of the RON. Research also suggests that these processes are represented in individual subcomponents of the RON. The current set of studies presented here sought to unpack how these two mechanisms work together to create the RON and allow for successful reorientation.

Study 1 investigated this relationship through a comparison of younger adults with older adults, a group known to have difficulties with both working memory and attention, on a modified auditory oddball task. Overall, the older adults were both less accurate and slower to respond to stimuli; however, they showed no sign of increased distractibility. This behavioral difference was accompanied with smaller peak RON amplitudes for the older adults. Interestingly, the correlation between the latency of the RON and behavioral success differed in direction between the two age groups, suggesting a central difference in the way the RON produces reorientation. Study 2 expanded on this relationship by separately manipulating both attention and working memory within an oddball paradigm. Results indicated that the specific interactions between the two RON mechanisms are more complex than previous research has suggested. In general, the results demonstrate that, in certain circumstances, participants switch from a greater reliance on working memory mechanisms to dependence on attentional processes and vice versa. This is evidenced by unexpected increases and decreases in the amplitude of the RON as well as opposing correlations found between RON amplitude and accuracy. On the whole, these two studies confirm that both attentional and working memory manipulations modulate the RON. However, the current studies also suggest that these processes both individually as well as interactively produce the RON and that the separation of the two mechanisms is not as strongly defined by the subcomponent of the RON as has been suggested in previous research.

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