Merel Keijzer (University of Groningen) & Monika S. Schmid (University of Essex)
Healthy aging; Language proficiency; L1 attrition; Working Memory (WM); Set shifting tests; Language use ; Dutch; English
Recent years have seen a host of studies on healthy aging. The topicality of healthy aging fits in well with the increasingly larger proportion of elderly in developed countries . It is well documented that cognitive resources tend to decline with age: processing speed, working memory, attention span and inhibition mechanisms are all reported to suffer due to changes in the neural substrate . It is equally well known that such cognitive decline impacts on language. Intriguing in this respect is the now well-known research trend on cognitive and language controls in bilinguals. This work suggests that early bilinguals may possess a safeguard against age-related cognitive decline, even to the extent that the onset of dementia can be delayed substantially , . However, mixed findings characterize this line of research, and even more so when late bilinguals are investigated. Not only is language and cognitive control in elderly late bilinguals vastly under-researched, but even studies on college-aged late bilinguals are far from uniform in their outcomes: while some work has found cognitive advantages for late bilinguals in their 20s, others have not , , .
In this study, an attempt is made to shed more light on this issue by examining a group of older (71+) late Dutch-English bilinguals, all L1 Dutch long-term émigrés in Australia. They took part in a series of language tests (comprising among other things language use and history questionnaire, vocabulary, and grammar measures) and cognitive measures (consisting of several working memory tasks, inhibition tasks, processing speed measurements, and set shifting tests). Their data were compared against youngest old (60-70) and middle-aged (40-50) controls. In addition, data was collected from age-matched Dutch and English monolingual control groups. The results show that, rather than the bilinguals outperforming the monolinguals as a group, individual differences very much characterize the findings. A three-way distinction emerged where a subset of the older bilinguals performed on a par with the monolinguals, while two other subsets produced markedly lower and markedly higher scores than the monolinguals, respectively. In other words, while a subset of the data appear to point in the direction of a bilingual cognitive advantage, another part of the data support an ‘overloading’ hypothesis where bilingualism hampers rather than facilitates performance on cognitive and language measures. Yet another subset suggest an indifferent result of late bilingualism. Although the oldest group often did produce poorer scores than their younger peers, this was not uniformly the case and the best performing oldest subjects often outperformed their younger peers on language and cognitive tasks alike.
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