Bilingualism and cognitive reserve: unlocking the benefits of multilingualism

Authors: Patricia Fuente García & Victoria Cano Sánchez are pedoctoral researchers at the University of the Basque Country, Dep. Of Linguistics and Basque Studies (UPV/EHU) and members of The Bilingual Mind Research Group (Gogo Elebiduna)

Bilingualism, or the ability to speak two or more languages, has become increasingly important in today’s globalized world. Not only does it facilitate communication and cultural understanding between people of different languages and backgrounds, but it has also been shown to have cognitive benefits that can help promote healthy aging. Research has shown that bilingualism may play a key role in promoting cognitive reserve, which refers to the brain’s ability to maintain function and structure despite age-related changes and disease. This is particularly relevant as the global population continues to age, with an estimated 2 billion people over the age of 60 by 2050 (World Health Organization, 2022). With age comes an increased risk of cognitive decline and dementia, but recent studies (see Gallo et al., 2022 for extensive review) have suggested that bilingualism may help delay the onset of these conditions.

The idea that bilingualism may be protective against cognitive decline is not new. In fact, studies from as early as the 1960s (Peal et al., 1962; Hakuta, 1969; Lambert, 1967) have suggested that bilingualism may have cognitive benefits, particularly in terms of executive function, the set of mental processes that allow us to plan, focus, and adapt to changing situations. However, it is only in recent years that researchers have started to explore the potential link between bilingualism and cognitive reserve in more depth.

Breaking down some benefits of being bilingual

One of the key cognitive benefits of bilingualism is enhanced executive functioning. In this regard, bilinguals have been shown to outperform monolinguals in linguistic and non-linguistic tasks that tap onto core aspects of the Executive Function (EC) system (see Bialystok, 2017 for a review). Aspects such as interference inhibition, i.e. suppressing irrelevant or conflicting information (Costa et al., 2008), or cognitive flexibility, i.e. shifting their attention or mental state as a result of a change in the context (Seçer, 2016). In healthy older adults, cognitive aging is most striking in tasks involving EC functions, and bilinguals outperform once again monolinguals in several tasks tapping into these functions (Bialystok et al., 2016). Hence, these studies support the idea that constantly managing and switching between two language systems results in enhanced EC functions, which in turn helps preserving cognitive reserve.

Another way in which bilingualism may promote cognitive reserve is through the concept of neural plasticity. The brain is a complex and dynamic organ that is capable of changing and adapting in response to experiences and environmental factors. Learning and using a second language is thought to stimulate the brain in ways that may promote neural plasticity and enhance cognitive reserve. Bilingualism has been shown to promote neuroplasticity. In fact, some studies using functional magnetic resonance imaging (fMRI), have found that bilingual individuals exhibited increased activation in brain regions associated with cognitive control and language processing (Gallo et al., 2022). It is also known that bilinguals have increased grey matter density, i.e. the tissue containing neurons and synapses, than monolinguals (Mechelli et al., 2004). Additionally, bilinguals have greater white matter integrity, i.e. the fibers connecting different parts of grey matter (Cummine et al., 2013). The bilingual brain, due to its higher neural reserve, is suggested to possess a greater ability to withstand neurological damage compared to the monolingual brain (Perani et al., 2015). Additionally, bilingual individuals demonstrate improved compensation for any loss of neural structure by having increased connectivity between different brain regions (Luk et al., 2011). This suggests that bilingualism may lead to rewiring of neural networks, optimizing cognitive functioning and supporting cognitive reserve.

Bilingualism as a bridge to current societal challenges

Understanding the benefits of bilingualism for cognitive reserve has broader implications for society. As multilingualism becomes increasingly prevalent, promoting bilingual education and language learning programs could have far-reaching benefits for individuals’ cognitive health. Healthcare professionals can recognize bilingualism as a protective factor and incorporate language-related activities into cognitive rehabilitation programs for individuals at risk of cognitive decline. Educators can develop inclusive and multilingual classrooms that celebrate language diversity and provide opportunities for all students to become bilingual. Moreover, bilingualism holds promise as a potential intervention for individuals with neurodegenerative diseases such as Alzheimer’s. By engaging in language learning or maintaining bilingualism, individuals may be able to delay the onset of cognitive symptoms up to five years, enhancing their cognitive reserve (Bialystok et al., 2016; Gallo et al., 2022). This could significantly improve the quality of life for individuals and reduce the burden on healthcare systems. However, it is important to acknowledge that bilingualism alone cannot prevent or cure neurodegenerative diseases. Bilingualism should be seen as one piece of the puzzle in promoting cognitive health and resilience. Maintaining an overall healthy lifestyle, including physical exercise, a balanced diet, and social engagement, is essential for optimal cognitive functioning and overall well-being.

All in all, the latest research provides compelling evidence that bilingualism plays a significant role in promoting cognitive reserve and enhancing cognitive abilities throughout the lifespan. Bilingualism offers a range of cognitive advantages, including improved executive functions, attentional control, memory, and neural plasticity. Embracing bilingualism not only benefits individuals but also enriches societies by fostering cultural understanding, communication, and diversity. As we strive to unlock the potential of the human brain and promote healthy aging, bilingualism emerges as a powerful tool. By investing in bilingual education, language learning programs, and inclusive language policies, we can empower individuals to embrace their linguistic potential and cultivate cognitive reserve. Let us recognize and celebrate the cognitive benefits of bilingualism, harness its potential, and create a future where language diversity and cognitive well-being go hand in hand.

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