Abstract 

Introducing bilingual experience as a healthy cognitive aging tool

The average age of the world population is expanding rapidly because of a decline in birth rates and an increase in life expectancy in the past decades. However, a longer life does not necessarily equal a healthy one. As aging goes hand in hand with an increased risk of diagnosis with Alzheimer’s disease, which is the most common form of dementia, the number of people with dementia is projected to sharply increase in the coming years. Research suggests that engaging in complex experiences in life may mitigate cognitive decline and delay the onset of dementia symptoms, promoting cognitive health in later life. Among these experiences, learning and speaking multiple languages have been suggested to also contribute to such a protective mechanism, but under what circumstances this emerges is not well-understood.

In this talk, I will present my PhD research, which explored how bilingual experience might influence cognitive aging in two complementary research lines. Part I of my research focused on the relationship between lifelong bilingualism and cognitive performance across adulthood in the northern Netherlands, using data from Lifelines, a population study of residents in Groningen, Fryslân, and Drenthe. In Part II, I examined whether introducing a bilingual experience later in life, in the form of a language learning intervention, could improve and maintain cognitive functioning in older adults with varying levels of cognitive decline.

Overall, my findings suggest that speaking multiple languages and later-life language learning as cognitive challenges are indeed associated with better cognitive functioning in older age to some degree. However, in line with recent frameworks in the field, I argue for specific conditions shaping these effects. To illustrate this complexity, I developed an analogy between the neurocognitive effects of bilingual experience and a mountain hike. Just as a hiker’s journey is shaped by their previous hiking experience, the hiking trail, and the weather conditions, the neurocognitive adaptations through bilingual experience depend on a complex and dynamic interplay between individual characteristics, the nature of the bilingual experience, and environmental factors.