**Abstract**

Becoming multilingual has a broad impact on cognitive abilities, especially visual processing. An important theoretical issue is whether the acquisition of distinct script systems affects face processing in an identical way, or, if not, how this acquisition may exert differential impacts on face processing. By reviewing the existing literature, we propose that Asian participants with the logographic script system differ from Western counterparts with the alphabetic script system in viewing faces. The contribution of the chapter is to identify the possible role of types of script systems in face processing mechanisms and to put forward the research direction in the future with several new methodological efforts.

**Keywords:** bilingualism, script system, face processing, neural recycling hypothesis, literacy acquisition

## **1. Introduction**

As globalization progresses worldwide, more and more individuals have become bilinguals or even multilingual. Multilingual differ from monolinguals in at least two aspects. First, multilingual usually have a larger vocabulary size compared with monolingual because these multilingual need to use words from different languages to express the same concept. Second, multilingual may have to deal with differences in many linguistic aspects of different languages, such as word-to-sound mapping, phonemes and the number of letters/letters, and orthography/word forms [1]. Such differences affect cognitive abilities (visual working memory [2], attentional control [3]), and efficient communication [4, 5] of multilingual. However, little attention was paid to the question of how acquiring different script systems, for example, with different phonological transparency of orthography and different visual configurations, impacts the visual perception of words, and even non-words (such as faces).

Before discussing the relationship of the acquisition of multiple script systems with face processing, we first reviewed the link of the script system to face processing in a single language. One important aspect of literacy acquisition is to use script systems to write and read in daily life. An interesting and fundamental issue underlying literacy acquisition is how our brain deals with faces. Why does literacy acquisition (in particular, what script system is learned to read) affect face processing? One dominant view, i.e., the neural recycling hypothesis [6], has been proposed. Since the script system is not fully formed until 5000 ~ 6000 years ago due to a recent cultural invention, unlike faces, it is possible that our brain does not evolve in time to develop a specific cortical territory dedicated to processing words, relative to faces. This invention of the script

system inevitably invades the pre-existing brain cortex, originally acted as other functions (such as recognizing faces and other objects), and re-organizes these brain structures to adapt themselves to word processing. That is, the process of acquiring a new script system may share some neural resources with recognizing faces. This opinion is called the neural recycling hypothesis [6], which assumes that: first, the anatomy of connection constrained strongly by the evolutionary pressure determines our brain organization, which, in turn, guides our subsequent learning. Second, learning to read must find suitable neural substrates, which are a set of circuits close enough in their function and revealing enough plasticity, in order to recycle a large part of the circuits for this new function. Third, although these other-serving cortical territories are (partially) occupied by literacy, their prior organization is never completely erased. Thus, prior neural constraints have a powerful impact on the acquisition of cultural invention and individual brain organization. Based on this recycling process, it is reasoned that literacy acquisition most likely has much to do with face processing.

This chapter is organized as follows. We first briefly introduced empirical evidence with respect to the impact of literacy acquisition on linguistic and non-linguistic (especially face) processing. Then, experimental evidence on cross-linguistic and cross-cultural comparisons provided insights into the role of script systems in processing faces, which echoes controversies about two kinds of theoretical hypotheses, i.e., language specificity and cross-language universality. Moreover, multilingual differences in face processing could be accounted for by different possibilities, such as the perceptual expertise hypothesis and attention-reshaped-by-language hypothesis. Finally, further studies are encouraged to increase the weight of the script system in explaining face processing (or reduce the weight of social and cultural interpretation) and to distinguish the visual form of the script system and the role of speech in face processing.
