Bilingual brains - does age matter?

by Lauren Probert 

Bilingualism—the goal of many a language student, spurred on by many factors - such as the inevitable second-hand embarrassment of our monolingual parents massacring the language on every holiday. But is fluid communication the only advantage? Studies into bilingualism and our brains could show otherwise.
​
The topic of bilingualism has been polemical amongst researchers for years, with scientists and linguists alike still divided on its benefits and disadvantages. On one hand, there is some evidence to suggest the existence of a ‘bilingual advantage’ concerning enhanced executive functioning (brain plasticity and increased cognitive reserve) and how bilingualism could be potentially aiding stroke recovery and dementia prevention. On the other hand, bilingualism’s former and less favourable reputation is built on some remaining researchers who argue that there is a ‘processing cost’--referring to the longer time taken to select the target language and suppress the other language—which presents lexical and syntactical disadvantages to a language-learner.
 
However, one could argue that there is evidence of oversimplification in this field of research. In particular, the diversity in age amongst the bilinguals researched-- most importantly the age at which the bilingual acquired its their second language and how bilingualism affects the brain at different stages of each subject’s life. 

The ‘critical period hypothesis’ states that children learn languages more easily because of the plasticity of their brains, which allows them to use both brain hemispheres in language acquisition. Language processing typically occurs in the left (logical) hemisphere but given the more emotional role of the right hemisphere, using both may mean that children can get ‘a more holistic grasp’ of different language’s ‘social and emotional context’ (Mia Nacamulli).

Therefore, children often find it easier to pick up on the subtleties of language. This initial utilisation of both hemispheres means that both will now be activated throughout the bilingual’s life, preventing the loss of some neural pathways. However, because language acquisition is easier in childhood, there is less of a ‘mental workout’. 
 
Peak mental age in humans is assumed to be in the mid 20’s, thus young adults already have comparatively enhanced executive functioning. Leading researcher Ellen Bialystok felt that Professor Kenneth Paap’s criticism of the benefits of bilingualism was ‘selectively focusing on studies of young adults, who are least likely to show a bilingual advantage; they’re already at the peak of their cognitive powers.’

Interestingly, elderly people may benefit most. Some studies have shown that elderly bilinguals have better-maintained white matter in their brains compared to elderly monolinguals. The heightened difficulty of learning languages in elderly life is beneficial because ‘as people gain new experiences, nerve pathways that are used frequently develop stronger connection, whereas neurons that are rarely or never used eventually die’ (Mike Cardwell and Cara Flanagan). This means bilingualism keeps the neurons in the left and right hemispheres active. Plus, the benefits are not reserved for elderly people with many years of bilingualism-- Boyke et al (2008) found that there was evidence of brain plasticity amongst 60-year-olds that employed a new skill, which could be applied to language learning. They also found increases in grey matter in the visual cortex. So, it does seem possible that neglecting to recognise age, specifically that at which bilingualism was obtained, may have led to some research inconsistencies. ​

Frustratingly, research into the basis of bilingualism is plagued by a ‘reproducibility crisis’ (Ed Yong) in which results showing a bilingual advantage have failed to be consistently replicated. This has damaged the credibility of research and caused ‘conclusive’ evidence to be questioned. Tests have also come under scrutiny due to inconsistency as the lack of control in terms of the subjects assessed is detrimental to the accuracy of their result. Other factors such as economic, cultural, health, education, or even a bilingual’s greater experience in resolving a conflict of stimuli, may all play their role. ​

Unfortunately, one cannot underestimate the extent to which the issue has become politicised. Bilingualism’s dramatic image makeover may be partially due to political rather than scientific influence, no thanks to those who objected to bilingualism socially and spread misinformation to do with scientific ideas linking bilingualism and mental degeneration, masquerading politics as science. 
 
Nowadays, the opposite opinion is more prevalent. Amongst the bilingual controversy there is “undoubtedly some concern” that it could reverse the “positive press” bilingualism has enjoyed because of the claims of cognitive benefits (Marek Kohn). It could be argued that recent data has been manipulated to support bilingualism given the social inclusion it is seen to engender. 
 
This has provoked an interpretation and publication bias. In one instance, a group of researchers used 104 abstracts on bilingualism and reported “68 percent of abstracts that found an executive-function advantage were eventually published in journals, compared to just 29 percent that found no advantage” (Ed Yong). So, we can quite clearly see here that there may be potential inaccuracies not only in the data, but in what data is presented. 
 
So, it’s obvious from all this that the proposition of a ‘bilingual advantage’ is clearly controversial and that an incomplete knowledge of linguistic processing, an absence of collaboration in this field, an unfortunate political agenda and a conflict between some leading researchers has only exacerbated problems. 
 
But even if we gloss over all those issues, recognising the inherent flaws in research to-date and the imperative for more accurate and in-depth testing, personally I would still argue that age does establish a diversity amongst bilinguals with varying potential cerebral benefits. Additionally, I think we can all agree that being able to communicate with people outside of your own culture and upholding attachments to the countries and people connected with their language is an uncontested value of bilingualism, regardless of age. 

Edited by Rosie Bell