Dissociating Spatial Attention and Working Memory Storage with Pupillometry

Extant work establishes a close relationship between spatial attention and working memory (WM) storage. Indeed, spatial representations of memorized items emerge spontaneously, even when space is completely task-irrelevant. Nevertheless, accumulating evidence suggests that the number of stored objects in WM can be tracked independently from the distribution of spatial attention, suggesting that these are separable aspects of attentional control. We examined this issue by analyzing pupillometric data from three change detection experiments (total n = 67) wherein the extent of spatial attention and WM load were manipulated independently. Results showed that pupil size tracked the number of attended locations and the number of memorized objects independently in each experiment. This dissociation held across distinct task designs and was present for both visuospatial and auditory WM. The current findings challenge unitary models of attention and instead demonstrate spatial attention and WM gating to be distinct aspects of voluntary attentional control.