Transsaccadic Memory: Working Memory in Action

Transsaccadic memory is the process by which visual information is maintained and spatially updated across eye movements. Transsaccadic memory resembles general visuospatial working memory in many ways, but it is unclear whether the two functions do share common faculties, or if the transsaccadic functions are underpinned by specialized mechanisms given the unique demands of maintaining spatial constancy across eye movements. Six experiments are presented in this thesis to address this question. In Chapter 2, I found that transsaccadic memory performance is predicted by performance on a 2-Back task, demonstrating commonalities with general visuospatial working memory. I also found, however, that performance on a change detection task did not predict transsaccadic memory performance, indicating a dissociation between a well-established contemporary measure of visuospatial working memory and transsaccadic memory. Change detection performance also failed to predict performance on the 2-Back task, so in Chapter 3, four variants of the change detection task were created to test possible explanations for the dissociations. All change detection tasks correlated strongly with the standard change detection task, but a correlation with the 2-Back task was seen only with a change detection variant where the availability of contextual spatial information during the test phase was minimized. This version of the change detection task was then tested against the transsaccadic task in Chapter 4, along with 2-Back and a no-saccade baseline for the transsaccadic task to isolate saccade-related performance components. Doing so, two saccade-related components were found that predicted performance on the working memory measures, though only one of these components explained variance across all tasks. I conclude that transsaccadic memory does appear to share faculties with general visuospatial working memory, but that like visuospatial working memory itself, it is a multifaceted construct.Ph.D