Abstract
Recently, Halberda et al. (2006, Psychol. Sci.) showed that with displays containing multiple spatially overlapping sets presented simultaneously, observers can successfully enumerate three such sets (two subsets plus the superset of all items). Here we aim to answer two questions related to this observation. First, we asked whether the selection of sets includes everything on a display, or whether it can be restricted to only the task relevant sets. We introduced a set of grey distracter dots to every display - effectively adding another colored set - and instructed observers to ignore them. We found that performance did not decrease with the addition of these grey dots, even on the enumeration of the superset which required the exclusion of all the grey dots. Second, we asked whether the three set limit is a result of the simultaneous presentation method used and whether more sets may be enumerated when sets are presented sequentially one at a time. We found no change in observers’ enumeration capacity in sequential displays compared to that obtained from simultaneous displays. This indicates that not only does the presentation method have no influence on the enumeration of multiple sets, but also that the superset can be summed across multiple sequential presentation.