Mental rotation differences between Chinese characters and English letters

We investigated mental rotation and rotational uncertainty effect of Chinese characters and English letters, respectively by event-related potential (ERP) and behavior responses. The results indicated that subjects could mentally rotate Chinese characters and English letters at similar speed, but the total response time (RT) for Chinese characters was significantly longer. Rotational uncertainty effect was more prominent for Chinese characters than English letters in both behavior results and the amplitudes of P300 component. With the increase of orientation angle, the left-hemispheric dominance of P300 component was observed for English letters at parietal area, while Chinese characters did not show evident hemispheric asymmetry. Our results implied that significant difference of RT and ERP between different stimulus types is supposed to be in the sub-stages of the stimulus perceptual encoding and/or parity judgment.