This chapter explains how counting relies on a set of attention pointers that individuate targets of interest and specify their locations independently of eye movements. Because after-images move with the eyes, it is impossible to bring individual items or subsets of items to the fovea one after the other, eliminating any role for eye movements. The selection and individuation of items relies on a set of attention pointers that are limited only by their spatial resolution. When inter-item spacing is closer than the size of the attentional selection regions, crowding prohibits access to individual items. Counting in moving displays even with long exposures cannot make use of a space-based strategy to keep track of counted items either. Attentional resolution is not uniform across visual space being, like visual resolution, much finer in the fovea. For this reason, eye movements are often required to bring fine details to the foveal area in dense displays in order for them to be selected and counted.
|Original language||English (US)|
|Title of host publication||Space, Time and Number in the Brain|
|Number of pages||13|
|State||Published - 2011|
Bibliographical noteFunding Information:
This work was supported by a Chaire d’Excellence and an NIH grant (EY09258) to P.C., by NSF grant BCS-0818588 to S.H. We thank Katherine Himes and James Intriligator for their invaluable contributions to the afterimage experiment.