Brain Activity Comparison during Abacus Calculation, Abacus-Based Mental Calculation, and Oral Reading: Implications for Metacognition

This study employed a single-case (N = 1) experimental design involving a 9-year-old boy. Brain activity was measured across 10 sessions between March and April 2025. We used functional near-infrared spectroscopy to measure frontopolar brain activity during four cognitive tasks- abacus calculation (AC), abacus-based mental calculation (AMC), oral reading of familiar text (OR_F), and oral reading of unfamiliar text (OR_UnF). In the AC task, calculations were performed using a physical abacus, whereas the AMC task was performed by mentally visualizing an abacus and tended to involve higher frontal pole activity than other tasks. In particular, the AMC task showed a moderate effect size on channel 8 compared with OR_F (p = 0.065, d = 0.637), although the difference was not statistically significant. From an educational perspective, these findings suggest that AMC may be associated with a process resembling self-regulated learning that involves self-monitoring and strategic cognitive control. Meanwhile, the results indicate that cognitive resources during OR_UnF are predominantly allocated to decoding processes, potentially leading to a relative decline in higher-order metacognitive activities. Furthermore, it was suggested that prefrontal cortex activity may vary during oral reading of familiar texts depending on the learner’s engagement and self-monitoring strategies. Overall, the results suggest that task difficulty and learning support conditions influence patterns of metacognitive engagement. However, the present study’s limitation to a single case necessitates larger-scale research to generalize the findings.