An ERP Study Of The Role Of Native Writing System In Picture Processing

Abstract

Introduction The present study aimed to examine the possible influence of one’s native writing system in visual processing of nonverbal material. We tested two trilingual groups of participants with either Korean or Japanese as L1, and both Chinese and English as L2s, and two control groups of native speakers of Chinese and English. The two trilingual groups represent very different L1 orthographic experiences, and the two L2 writing systems are likewise known for their drastic differences in word form and mapping between orthography and phonology. Method and Results A go/no-go repetition detection ERP task was employed with mixed presentation of words and pictures. Trilingual participants performed the task with English and Chinese words in separate blocks. Our analysis focused on picture trials in the two blocks. Within-subject responses in N170 and N400 to picture stimuli were not expected to differ between the two language conditions, while between-subject responses may differ if picture processing was influenced by literacy experience. When the trilingual groups were compared with the control participants in the respective blocks, processing of pictures in Japanese participants tended to be more similar to the Chinese control group, both showing greater negativity in N170 and less negativity in N400 relative to the Korean group. In the English condition, the Japanese group had greater N170 amplitude than both the Korean and English groups, while the three groups significantly differed from each other in the N400 (in decreasing order of negativity: Korean > English > Japanese). Given the differences between the Japanese and Korean groups, and in relation to the control groups, further analysis focused on the two trilingual groups, while controlling for individual differences in picture naming accuracy and self-reported degree of usage of Chinese and English, as well as between-item differences including visual complexity and pictured object familiarity. A main effect of group was found, with the Japanese group showing greater negativity in N170 and smaller N400 than the Korean group. Interestingly, pictures were processed differently depending on the language context-- pictures embedded among Chinese characters elicited greater N170 and more attenuated N400 than pictures presented among English words. A significant interaction indicated that the language block difference in the N400 was driven by the Korean group showing greater N400 in the English than the Chinese block, but no difference was shown by the Japanese group. Discussion Following previous studies, more negative N170 and N400 are taken to reflect greater visual expertise and processing difficulty, respectively. As such, the patterns exhibited by the Japanese participants suggest greater ease in processing pictures and minimal influence of language context, perhaps due to their familiarity with Kanji characters and the Romaji script of Latin letters. Kanji, derived from Chinese characters, are believed to require more visuospatial analysis. This account also suggests that the Korean participants were susceptible to influence of language context. In particular, more negative N400 to pictures among English than Chinese words implies greater processing demand associated with switching between alphabetic word forms and pictures.