Post written by François Grosjean.
Canadian and French author Nancy Huston is married to a Bulgarian-French bilingual and their common language is French. In her book, Losing North, she worries that their communal old age will be quasi-autistic. She writes: "At first our acquired language will desert us bit by bit..... Eventually, with French totally erased from our memories, we shall sit in our rocking-chairs from dawn to dusk, nattering incomprehensibly in our respective mother tongues" (p. 43).
Recent research findings should reassure Nancy Huston and her husband. Of course, old age has an impact on language. In the domain of speech perception, discrimination of sounds is poorer, more complex speech as well as fast speech create difficulties, and information is stored less well. This is true also of language production where one observes word-finding difficulties particularly of proper names. But these age-related processing deficits are found in both monolinguals and bilinguals.
Two recent studies appear to show, in fact, that elderly bilinguals do better than their monolingual counterparts. In the first one, York University cognitive psychologist Ellen Bialystok and her collaborators used the Simon task to study inhibitory control in monolinguals and bilinguals. Participants were asked to look at a computer screen and to press the response key marked X when they saw a red square, and the key marked O when they saw a blue square. In congruent trials, the red square appeared above the X key and the blue square above the O key; in incongruent trials, the red square appeared above the O key and the blue square above the X key.
The Simon effect was replicated, that is the participants responded faster when the colored square appeared on the same side as its corresponding key, and slower when the color and its associated key were not on the same side. But the interesting finding was that the 60-80 year old bilinguals were faster than the matched monolingual group on both congruent and incongruent trials. The authors suggest that a lifetime of managing two (or more) active language systems (choosing one language, or the other, or both during bilingual speech; see here) has given them an advantage in executive functions that are responsible for managing attention as in the Simon task.
In a second study, published two years later, Ellen Bialystok and her collaborators made a discovery that has been relayed around the world. They showed that being bilingual may well delay the development of dementia in old age, that is disorders that impact memory, language, motor and spatial skills, problem solving and attention. Alzheimer's disease is a common cause of dementia but there are also other reasons such as brain injury and brain tumors. Half of the patients with dementia they examined were bilingual. In addition, they had spent the majority of their lives using both languages.
The authors found that the age of onset of the symptoms of dementia was significantly different in the monolingual group and in the bilingual group: the latter showed a mean age of onset of dementia 4.1 years later than the monolingual group. Ellen Bialystok and her colleagues argued that the attentional control that bilinguals use to govern their languages is similar to complex mental activities that are known to protect against dementia.
In a very recent study, the same research group concentrated only on patients diagnosed with Alzheimer's disease and found similar results. In addition, they showed that the effect is not attributable to confounding factors such as education, occupational status or immigration. They were careful to add that bilingualism does not in any way prevent Alzheimer's disease but that it appears to postpone the onset of its symptoms.
In sum, Nancy Huston's worry of a "quasi-autistic communal old-age" with her bilingual husband is not founded. In fact, it could well be that the two of them have, along with other bilinguals, a few cognitive benefits in their favor!
Huston, N. (2002). Losing North: Musings on Land, Tongue and Self. Toronto: McArthur.
Bialystok, E., Martin, M., and Viswanathan, M. (2005). Bilingualism across the lifespan: The rise and fall of inhibitory control. International Journal of Bilingualism, 9, 103-119.
Bialystok, E., Craik, F., and Freedman, M. (2007). Bilingualism as a protection against the onset of symptoms of dementia. Neuropsychologia, 45, 459-464.
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