[Effects of size-equivalence and symmetry in enumeration tasks]

Previous research has shown that in enumeration tasks, "subitizing" is a rapid and an accurate process used with 1-4 items, and that "counting" is a slow and an inaccurate process used with over four items. It has been suggested that the former task is preattentive, whereas the latter task is attentive. We investigated whether item-size invariance and pattern symmetry affected subitizing and counting speeds. Participants enumerated dots, which were continuously presented, as quickly and as accurately as possible. Results of Experiment 1 indicated that the variance of dot-size was independent of enumeration time, suggesting that the variance in attentional allocation to each dot affected neither subitizing nor counting processes. Results of Experiment 2 indicated that pattern symmetry did not increase the capacity for subitizing, but increased the speed of counting. These results suggest that the capacity of subitizing is four items regardless of item-size invariance and pattern regularity. Moreover, the pattern configuration affected the speed of counting, whereas item features did not.