Subitizing In Serial Counting Task

Judge the numerosity of a set, i.e., magnitude enumeration, it is important for human survival and adaptation. For enumerating a smaller number of items, the process is rapid and accurate; this is referred to as subitizing. This is a universal phenomenon, not only in adults, but also found in infants and animals, estimation is a rapid but imprecise strategy for large sets; cdunting is an accurate but time-consuming strategy for larger sets. At present, the main concern is underlying mechanisms for small and large numbers. Some studies suggest that there is a shared estimation system for small and large quantities in human, which conforms to Weber’s law. However, some studies suggest that there is a cognitive mechanism dedicated to small sets of objects. In this study, we investigate this question by sequentially presented visual stimuli and ask participants to counting.The results of Experiment 1 demonstrated a subitizing phenomenon in serial counting task. Experiment 2 aimed to rule out the possibility that the subitizing found in Experiment 1 was due to a temporal estimation rather than a numerical counting.Experiment 2 had two critical conditions, i.e., a continuous item presentation and an interrupted item presentation. The observed data in Experiment 2 showed a significant main effect of presentation mode. Thus, we can confirm that our participants did perform serial counting, as they were instructed, rather than temporal estimation in the rapid serial counting paradigm. Experiment 3 aimed to extend the finding of Experiment 1 by exploring potential dependency of subitizing on SOAs and relative ratios (RR) between the durations of the stimuli and the inter-item intervals on the display, we found that relatively lower (400ms in Experiment 3a) or higher (100ms in Experiment 3b) SOAs disrupted the basic effect of subitizing, it seems that the occurrence of subitizing is notdependent on the relative ratios (RRs) between the durations of the stimuli and the inter-item intervals on the display. A paradigm of items with random colors was used in Experiment 3 to explore some potential explanations on subitizing. These results suggest that several alternative explanations, including color-based IOR, repetition blindness are not able to account for the subitizing in Experiment 1. To search for whether subitizing in serial counting task reflects object individuation mechanism, we adopt a dual-task paradigm, measure enumeration accuracy with and without concurrent VWM task, we found that working memory impairs precision in the subitizing range but not in the large numerosities .