Infant Adaptations to Bilingual Environments

Bilingualism is an increasingly important issue in society and politics. Currently, 1 in 3 children born in the UK have at least one foreign-born parent and 20% of children in primary school speak English as an additional language (ONS, 2021). With the rise of immigration and diverse multicultural communities, and the rapid growth of economies in the Middle East, Asia, and elsewhere, bilingualism has become a priority for organisations that range from the small (e.g., schools and local businesses) to the large (e.g., the United Nations). To meet this demand, and to maintain culture and identity, initiatives have been set up to implement bilingualism in the community (e.g., by the Welsh government). It is hoped that these initiatives will provide long term socioeconomic and cultural benefits. But what effect does widespread bilingualism have on children's development? This question is becoming pertinent, because evidence from my lab (which dovetails with more recent evidence from labs in Canada, the USA and Spain) suggest that exposure to a bilingual environment can affect the infant's cognitive development.

Although this new field of infant research is blossoming, it has no direction or theory. I have therefore introduced a theoretical framework based on known developmental constraints that can integrate the burgeoning empirical evidence and transform the emerging field. According to this theory (D'Souza & D'Souza, 2021), bilingual infants adapt to their more complex environments by switching attention faster and more frequently. These adaptations help the infant to bootstrap their language learning by allowing them to rapidly shift attention to speakers' lip movements. The adaptations also lead the bilingual infant to explore their environment more than the monolingual infant, impacting learning and development.

To test this theory and integrate findings, I will study infants longitudinally at a crucial period in development (5, 7.5, and 10 months). First, I will analyse the complexity of the infants' home and language environment. Understanding the context in which the child is growing up is crucial to understanding how the child will adapt to it. Second, I will observe how the infants adapt to different environments (e.g., do bilingual infants explore more than monolingual infants?). Third, I will use neuroimaging to measure the infants' brain activity as they explore different environments. This will elucidate relevant neural processes. Finally, I will use computer modelling to integrate the observational and experimental data. This will help us to explain the effect of bilingualism on infant brain and cognitive development.

To test the extent to which my theory can be applied, I will study infants from three different communities in London (Albanian, Lithuanian, Bangladeshi) as well as communities in Spain and Singapore. After 4 years, I will expand the population studied to include remote rural communities in Mexico and Papua New Guinea.

My research will lead to a step-change in our understanding of infant development, because it combines brain and cognitive experimental data with naturalistic observational data in the same group of children over time. The fellowship will also provide me with the opportunity to develop my mathematical and computational skills, and test my theories across different cultural contexts. This will help us to understand the effect of bilingualism on child development, ultimately addressing one of the major issues in current society.