The Basic Magnitude Processing Of Children With Different Level Of Number Sense:an ERR Study

Number sense or number knowledge refers to an understanding of numbers and numerical relationships (Jordan, Kaplan, Ramineni,&Locuniak,2009; Malofeeva, Day,&Saco,2004; Schaeffer, Eggleston,&Scott,1974; Siegler&Jenkins,1989), and it is a strong predictor of mathematics learning difficulties (Jordan et al.,2010; Locuniak&Jordan,2008; Seethaler&Fuchs,2010). Children with number sense disadvantage might become mathematical learning difficulties. According to the five components structure of Jordan’s group, the number sense is developing stepwise, and each component has a development order. Therefore, it is necessary to distinguish and research different levels of children’s number sense. Number cognition is one of the most important human cognitive abilities. People who know and understand numbers, have knowledge of arithmetic and computing skills, will help a lot in normal life, study and work. As the most basic elements of number cognition, basic numerical magnitude processing is also crucial to calculation and other more advanced mathematics skills (Butterworth,1999; Dehaene,1997). There are several studies suggest that basic numerical magnitude tasks are processed atypically in children with developmental disorders of numerical cognition, such as Developmental Dyscalculia (Ashkenazi, Mark-Zigdon,&Henik,2009; Landerl et al.,2004; Landerl&Kolle,2009; Mussolin et al.,2010), and the evidence from brain imaging studies found their brain mechanism and processing are different from their normal age companions. In light of this, relying on the excellent temporal resolution of electro-encephalography, the present study is to investigate the basic numerical magnitude processing of children with different development level of number sense.This study included two experiments:Experiment1:a group of42children in2nd grade were tested on the symbolic size congruity task to examine the behavioral and ERPs performance in automatic processing; Experiment2adopting symbolic number comparison task to further examine the cognitive characteristics of intentional processing of42children with different number sense level. The results revealed that:(1) In the automatic processing task (the physical size congruity paradigm), the size congruity effect and distance effect are both found in behavioral and ERPs, which indicates the exact number representations of children complete and intact;(2) The ERPs interference effect in the prefrontal electrodes and the stimulus-locked LRP in the group of children with number sense advantage suggests that their inhibition of irrelevant information and incorrect response tendency may be slightly damaged;(3) In the intentional processing task (the numerical comparison paradigm), we found the distance effect both in behavior and ERPs in all three groups about200ms after the stimulus presentation, which suggest the activation of the exact number representations. But for the children with number sense disadvantage, there is a wider activation in the cerebral cortex, which may be indicative of the involvement of attention and working memory for the task instructions.