**5. Future studies**

Despite much evidence from the cross-cultural and cross-linguistic studies that indicate differences in face processing, more efforts should be devoted to effectively dissociate possibly separate contributions of social culture and script system to the explanation of differences in face processing and to clarify how multilingualism affects face processing. Moreover, the relationship between the script system and face processing provides an important window into the understanding of brain plasticity. To answer the issue, we proposed to test multilingual speakers to unveil the impact of a distinct script systems on face processing. Several possible research directions are put forward, such as 1) training illiterates to acquire distinct script systems respectively in an identical culture; 2) comparing monolingual Chinese and Korean subjects sharing the East-Asian culture; 3) comparing monolinguals and bilinguals (or multilingual) speakers; 4) using one artificial language to train participants to either learn the visual form or the speech in communication.

### **5.1 Training illiterates to learn distinct script systems respectively**

One way to dissociate the contributions of social culture and script systems to holistic processing is to train the distinct types of script systems on illiterates from an identical social culture. Illiterates are a special population who share the social culture (including spoken language) with literates. One important distinction between literates and illiterates is that literates acquired the script system. Therefore, it helps to understand how a script system shapes the processing of faces in a particular social culture. Two previous studies, Ventura et al. [57] and Cao et al. [58], examined the relationships between the acquisition of a script system and face processing in the Western and the Eastern culture respectively. However, these studies cannot reveal the potential contributions of the distinct script systems to face processing because of the absence of a direct comparison. Based on the previous studies, we proposed one possible way of segregating the role of social culture from script system in face processing, in other words, we propose ways to heighten the weights of the script system in the explanation of face processing, thus merely representing the influence of different script systems on face processing after controlling social culture. More specifically, this can be achieved by teaching Western illiterates in Chinese and English respectively or teaching Chinese illiterates in Chinese and English respectively. Combined with a variety of experimental paradigms which tap distinct dimensions of holistic face processing, the relationships between script system and face processing could be systematically investigated.

## **5.2 Comparing face processing mechanisms between monolinguals and multilingual**

The first suggestion is proposed against the monolingual context. With the development of globalization, more and more individuals have become bilingual or multilingual. It is possibly easier for bilinguals to acquire the script system of a second language than master the social culture. Therefore, one viable way of

examining the relationships between distinct types of script systems and face processing is to recruit the monolinguals and bilinguals (or multilingual) and compare the differences between these groups. In this case, Chinese-English bilinguals (or multilingual) and Chinese monolinguals, whose mother tongue is Chinese, or English-Chinese bilinguals (or multilingual) and English monolinguals, whose mother tongue is English, are recruited to decrease the possible role of social culture in the explanation of face processing.
