A growing number of studies claim that spatial attention can be split "on demand" into several, segregated foci of enhanced processing. Intrigued by the theoretical ramifications of this proposal, we analyzed 19 relevant sets of experiments using four methodological criteria. We typically found several methodological limitations in each study that…

Although in traditional attention research the focus of visual spatial attention has been considered as indivisible, many studies in the last 15 years have claimed the contrary. These studies suggest that humans can direct their attention simultaneously to multiple noncontiguous regions of the visual field upon mere instruction. The notion that…