Comparing developmental neural incongruency effects in reading and arithmetic among children: An ERP study

Although reading and arithmetic abilities are considered distinct academic skills, evidence of shared cognitive structures suggests that they may also involve shared brain functions. This study investigated neural incongruency effects between sentence reading and simple addition in primary school children using event-related potentials (ERPs). Sixty children from grades 1, 2 and 3 judged whether the meanings of Chinese sentences and arithmetic additions were correct or not. ERP maps including all electrodes were analysed using timepoint-to-timepoint TANOVA analysis with factors of incongruency, task and age. Behavioural responses were faster in the congruent than incongruent condition, especially for younger children; the age-related reduction in the incongruency effect was more pronounced in the arithmetic than the reading task. TANOVA showed incongruency main effects for the N400 (306-476 msec) that were similar for reading and arithmetic. Importantly, interaction effects of task and incongruency in the early N400 (242-326 msec) time range reflected faster incongruency effects for arithmetic compared to reading. Age did not modulate any of these effects, nor had a significant main effect on ERP. Microstate findings revealed that the N400 effect differed between reading and arithmetic in latency and topographic distribution. Taken together, the results suggest that incorrectness in both reading and arithmetic is reflected by N400 effects that indicate incongruency processing, but this activity differs between reading and arithmetic and starts earlier for arithmetic than reading. Overall, the present study underscores the need for a cross-domain approach to understanding the shared and distinct neurocognitive patterns of academic skills.