Visual Working Memory Impairs Visual Detection: A Function of Working Memory Load or Sensory Load?

Public Significance Statement Previous load theory studies claimed that the working memory load of the visual working memory (VWM) task impaired visual detection sensitivity to incoming visual stimuli. The current study demonstrates that the sensory load due to perceptual processing of the memory array is the real determining factor. This work provides new insights into the current debate on how VWM and perception interact and sheds critical light on load theory. Researchers have explored the influence of visual working memory (VWM) load on visual perception in the past decade. One of their key findings is that a high VWM load leads to reduced visual detection sensitivity to incoming visual stimuli. However, recent studies imply that persistent sensory processing continues after the memory array is offset. It is possible that the impaired visual detection is due to the sensory load of the residual sensory processing of the memory array (sensory load account) rather than the working memory load of the VWM task (VWM load account). We performed four experiments to examine the impacts on visual detection. Experiment 1 manipulated the retention time of the memory array while keeping the VWM load constant, revealing reduced visual detection along with retention time. Experiments 2 and 3 manipulated the VWM load while maintaining a constant sensory load, and visual detection was not affected. Experiment 4 affirmed that the findings in Experiments 1-3 were reliable. Together, the results of the current study suggest that the residual sensory load, rather than the VWM load of the VWM task, impairs visual detection.