双语即时切换下非目标语言语音和语义的激活状态

本研究采用双语即时切换范式, 探讨非熟练中英双语者在对目标语言(启动词)语音或语义的加工过程中非目标语言的激活状态。实验1设置了与启动词的翻译对等词存在语音相关或无关的两类配对词, 要求被试进行语音判断任务, 结果表明, 不论哪种切换条件, 两类配对词在反应时和P200成分上都没有差异, 说明目标语言在语音加工过程中非目标语言的语音层面没有得到自动激活, 从而没有产生启动效应。实验2则设置了语义相关和无关配对词, 并进行语义判断任务, 结果在两种切换条件下都发现明显的语义启动效应及N400差异, 说明非目标语言在语义层面上有得到自动激活, 但激活的程度表现出切换方向上的不一致, L1-L2切换下的语义启动量要明显大于L2-L1, 并且L1-L2的N400差异主要表现在前部脑区, 持续时间更久, 而L2-L1的N400差异主要表现在后部脑区, 但持续时间较短, 表明对于非熟练的双语者来说, 不同切换方向下对共享语义表征的激活加工是不一样的。

The phonological or semantic activation of non-target language in an immediate cross-language switching paradigm

Bilingual individuals need to switch their languages to understand different language information in daily life, which is called bilingual comprehensive switching. Prior studies mainly focused on whether the non-target language was activated when bilinguals intended to understand the target language, while inconsistent results were concluded for methodological ambiguities in paradigms. Therefore, this study was designed to further investigate the activation of non-target language in language comprehension with an immediate cross-language priming paradigm and event-related brain potential (ERP) technique. Twenty Chinese-English bilinguals participated in Experiment 1 where the phonological decision task was conducted, and sixteen Chinese-English bilinguals participated in Experiment 2 where the conceptual decision task was conducted. All of participants were Chinese natives, and English was their unskilled second language. In each experiment, target words (one language) were presented immediately after prime words (another language) which were phonologically related with the translation equivalents of target words (Experiment 1) or semantically related with the translation equivalents of target words (Experiment 2). Participants were instructed to make phonological decision (Experiment 1) or conceptual decision (Experiment 2) to all words presented on the screen. The behavior data and ERP data were recorded and analyzed with target words. The results showed that, in experiment 1, there were no RTs or P200 difference between phonologically related target words and phonologically unrelated target words no matter the switching direction was L1–L2 or L2–L1. So there was no evidence of cross-language phonological priming, suggesting that the phonological representation of non-target language was not automatically activated when the target words were processed at lexical level. And in experiment 2, significant cross-language semantically priming was found on both behavior and ERP data. Semantically related target words produced faster RTs and a smaller amplitude N400 than semantically unrelated target words in both switching direction. More importantly, the results provided evidence for the priming asymmetry, with larger priming from L1 to L2 than the reverse, and different spatial and temporal N400 priming effect (the ERP difference between two types of target words) between two switching direction. N400 priming effect was distributed towards more posterior sites for L2–L1 switching during the typical N400 window (300-500ms), and N400 priming effect for L1–L2 switching was distributed to more anterior sites, but lasted to 500-700 ms. In conclusion, results from the current study provide evidence for the semantic activation of non-target Language during the conceptual decision task, and the semantic activation was asymmetry between L1–L2 and L2–L1. But no evidence was found for the lexical activation of non-target Language during the phonological decision task.