Optimal trans-saccadic integration relies on visual working memory

Saccadic eye movements alter the visual processing of objects of interest by bringing them from the periphery, where there is only low-resolution vision, to the high-resolution fovea. Evidence suggests that people are able to achieve trans-saccadic integration in a near-optimal manner; however the mechanisms underlying integration are still unclear. Visual working memory (VWM) is sustained across a saccade, and it has been suggested that this memory resource is used to store and compare the pre- and post- saccadic percepts. This study directly tested the hypothesis that VWM is necessary for optimal trans-saccadic integration, by introducing memory load during a saccade, and testing subsequent integration performance on feature similar and dissimilar stimuli. Results show that integration performance was impaired when there was an additional memory task. Additionally, performance on the memory task was affected by feature-specific integration stimuli. Our results suggest that VWM supports the integration of pre- and post- saccadic stimuli because integration performance is impaired under VWM load.