How Attention Affects Subitizing:An ERP Study

We can distinguish small numbers of objects,usually up to about four,very accurately and rapidly.This phenomenon is known as subitizing.So far,researchers suggest that subitizing is affected by attention.The accuracy of subitizing will be lower than usual if attentional resource is reduced.Although many behavioral experiments have shown the results of this effect of attention on subitizing,there is no in-depth study and exact explanation of how attention affects subitizing.This research mainly focuses on the relationship between subitizing and attention.Attention Blink paradigm was used to manipulate attentional resources.Subj ects were asked to judge the quantity of stimuli with specific shape characteristics.Meanwhile,the interaction between different quantity and attentional resources was observed by the N2pc components of EEG.We repeated the behavioral results of the past researches.Besides,we found that when subj ects had more attentional resources,they tended to judge the number as less than the actual number,and when they had less attentional resources,they tended to judge the number as more than the actual number.What's more,in the EEG results,we observed that attention could interfere with induction of N2pc components which should be correlated with quantity of stimuli.At the same time,the N2pc amplitude of subj ects in the correct trials was larger than that in the wrong trials when they had more attentional resource.Based on the existing theories,we suggest that the reduction of attentional resources makes us adopt Approximate Number System in subitizing,and Parallel Individuation system when we have more attentional resource.The more attention resources,the higher the efficiency of Parallel Individuation system.