ERP Study On Asymmetrical Switch Cost: Switching Between Languages In Different Language Families

Although bilinguals may have at least two options when they want to express some concept with language, they can effectively choose the right language needed in the current environment to make response, nearly without making mistakes because of the interruption between languages. Balanced bilinguals are of the same degree of proficiency in their two languages and can effectively finish the task of language selection. Unbalanced bilinguals can also successfully finish this kind of task, although their non-native language is obviously less proficient than their native language, and when speaking the weaker second language, they have to overcome the interruption resulting from the automatic response of their first language. For bilinguals or multilinguals, effective attention control is needed in the use of two or more languages. Therefore, it is important to have a better understanding of how bilinguals make choices between two or more languages, for it can help to enhance the effectiveness of attention control in bilingual expression and language selection. For this reason, many researchers have devoted themselves to exploring the use of two or more languages from the perspective of neural mechanisms with all kinds of experiments, a great number of which are about language switch. However, most of the studies about language switch are focused on two or more languages belonging to the same language family, such as researches on switch between Dutch and English or researches on switch between German and English, and the amount of those studies focusing on two or more languages belonging to different language families are relatively small, such as researches on switch between Chinese and English, or researches on switch between Japanese and English. Therefore, with unbalanced Chinese-English bilinguals as the subjects and by means of experiment of overt picture naming, this research aims to find out the answer to the question whether there is switch cost in the case of switch between languages belonging to different language families and to define the switch cost pattern if the answer to the above question is that switch cost does exist between languages from different language families, especially to test whether there will occur asymmetrical switch cost, a phenomenon often found in researches on switching between languages from the same language family with unbalanced bilinguals as the subjects.To reach the above goal, this research explores switch between two languages that belong to different language families by asking unbalanced Chinese-English bilinguals to finish the task of overt picture naming in ERP experiment. The analysis of behavioral data shows that under the condition of short preparation interval, the switch cost of first language (Chinese) is larger than that of second language (English); under the condition of long preparation interval, switch costs of first language (Chinese) and second language (English) are symmetrical. Besides, the effect of preparation interval exists under all the conditions in the experiment expect first language repeat. The above finding is identical with the first language repeat benefit hypothesis, which indicates that the length of preparation time also has influence on the symmetry of switch cost. The analysis of ERP data shows that N2 effect exists both in language switch responses and language repeat responses. What is more, it is larger under the condition of short preparation interval than that under the condition of long preparation interval in switch responses. As the existence of N2 effect is considered as the index of the existence of inhibition or conflict, it can be concluded from the above results that under the condition of short preparation interval, more conflict exists between those two languages than under the condition of long preparation interval. Therefore, under the condition of short preparation interval, it is necessary to overcome more conflicts. As a result, it is more difficult to finish the response tasks under the condition of short preparation interval than under the long preparation interval in the experiment of language switch, which leads to longer response time cost to finish the tasks under the condition of short preparation interval than under the long preparation interval.