Decoding the neural impact of radical complexity in Chinese characters during working memory task

Readers of Chinese characters need to recognize how they are formed in order to identify them correctly. However, our understanding of the cognitive processing of characters in working memory is limited. In Experiment 1, using the character N-back task paradigm, electrophysiological data were recorded from 26 participants to investigate the effects of the visual feature of radicals on neural activity during the character recognition, updating and maintenance in the N-back task. Results showed that compound characters required longer response times than single-component characters. For the event-related potentials (ERPs), the compound character condition had more negative N2pc and lower P300 amplitudes than the single-component character condition. In Experiment 2, data from 26 participants were used to analyse the effect of the phonological feature of radicals on neural activity during the character recognition, updating and maintenance in the N-back task. Results showed that there was a larger P200 in the irregular character condition than in the regular character condition, but there was no difference between the regular and the irregular characters in the N2pc, P300 and slow wave (SW) components. The visual feature and the phonological feature of the radicals may have different effects on the character processing. This study reveals the neural effects of Chinese character radicals on cognitive processing in a working memory task and provides behavioural and electrophysiological evidence for a theoretical model of verbal working memory subprocesses.