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Ellen Bialystok, OC, FRSC (born 1948) is a Canadian psychologist and professor. She carries the rank of Distinguished Research Professor at York University in Toronto, Ontario where she is director of the Lifespan Cognition and Development Lab. She is also an associate scientist at the Rotman Research Institute of the Baycrest Centre for Geriatric Care.
She received her Ph.D. from the University of Toronto in 1976 with a specialization in cognitive and language development in children.
Executive control is known to involve three main components including selective attention/inhibition, attention shifting, and working memory. In a separate study, Bialystok examined the difference in development and subsequent coordination of these three components of executive function in bilingual children as opposed to that of monolingual children. Two groups of children who were either monolingual or bilingual completed a complex classification task that required the use of either one or multiple components of executive control functions. This was done with the use of visual and/or auditory stimuli, where a single-modality version presented either the visual or auditory component, requiring the use of just one executive control component, and a dual-modality version that combined the two, and therefore required the use of multiple executive control components. The single-modality condition did not elicit significantly different performance by either the monolinguals or bilinguals, however, in the dual-modality condition that required the use of multiple components, bilinguals performed with much higher accuracy than the monolinguals.
Beyond this general advantage to cognitive development seen in bilinguals, there is remarkable evidence for an advantage regarding executive control in particular – specifically in cases where multiple components of this executive control is required for perform a task. This has implications for real-world situations, as multitasking is a common everyday function that bilinguals could possibly perform better at than monolinguals.
Regarding the reason behind this advantage, no definitive evidence has been collected. However, it is thought that because bilinguals must constantly shift between two languages, selecting the correct words from one while ignoring competing information from the other, that they have more practice in simultaneously using multiple components of executive functioning. Because bilinguals go through this process on a daily basis throughout their lifespan, they therefore gain an advantage over monolingual individuals who do not recruit this same simultaneous function as often.
Children's progress in their development of both English and French linguistic and metalinguistic skills were examined to assess how accurately their developing abilities matched those of fully bilingual children (those who had learned their second language at home), and whether or not the intensive French immersion was impeding their English language development. While the analysis of tasks concerning linguistic and metalinguistic abilities in both French and English found a variety of different patterns, many of those patterns matched that of the fully bilingual children. Thus, these children participating in this immersion program are not only able to truly become bilingual, but gain the advantages that come with bilingualism as well. Continued exposure to French as well as instruction in the formal structures of the language should only improve upon these children's developing linguistic skills.
Results demonstrated two different types of processing. Phonological awareness, which was strongly correlated across the two languages, suggests a common cognitive basis regardless of the language being learned. Word identification, in contrast, did not relate across the two languages, suggesting a specific ability governed by each individual language and its particular demands. In the case of bilingual children learning to read two different writing systems, phonological awareness appears to be a more generalized ability that can be transferred easily across languages, while word identification (and therefore reading) must be developed separately for each language.
In the response inhibition condition, both the monolinguals and bilinguals activated the same neural network and performed the task in the same amount of time. However, in the interference suppression trials, bilinguals activated different neural regions than monolinguals and also performed the task more quickly. The distinction in neural response between monolinguals and bilinguals indicates not only that interference suppression and response inhibition are cognitively distinct from one another, but also supports the idea that bilingualism provides an advantage in the cognitive control of inhibition concerning conscious attention (manual key pressing), but doesn't not seem to have a significant effect regarding the control of more instantaneous motor responses (inhibition of eye movements).
Bialystok, Craik, and Luk tested both younger and older monolingual and bilingual adults on a variety of tasks assessing working memory, lexical retrieval, and executive control to further investigate the specific ways in which bilingualism affects cognition, and how aging can modify these effects. The effect of the language group differed according to each task, where both monolinguals and bilinguals performed about similarly on working memory tasks, monolinguals outperformed bilinguals on lexical retrieval tasks, and bilinguals outperformed monolinguals on executive control tasks. Further analysis showed that bilinguals did, in fact, have inferior language knowledge as compared to monolinguals, yet similar working memory abilities. However, bilinguals did show overall superior executive control functions to their monolingual counterparts. In addition, the greatest levels of executive control were achieved by the older bilingual group, in accordance with the prediction that bilingualism throughout the lifespan attenuates the age-related deterioration of executive control tasks – those tasks that were nonverbal in nature, as bilinguals tend to do worse than monolinguals on linguistic measures.
Further work was done with groups of younger and older monolingual and bilingual adults in three consecutive studies investigating the persistence of the bilingual advantage into adulthood, as well as the notion that bilingualism provides a defense against the deterioration that aging brings on executive control. Bialystok, Craik, Klein, and Viswanathan found that results indicated a continuation of the bilingual advantage into adulthood, and a pattern that suggests a slowing of age-related decline in executive processes for older bilingual adults along with other positive effects in cognitive functioning, suggesting widespread benefits of bilingualism beyond what was originally hypothesized.
Bialystok, Luk, Craik, and Grady, using diffusion tensor imaging (DTI), measured the amount of white matter integrity in both monolingual and bilingual older adults. The results were consistent with the prediction and demonstrate a strong correlation between lifelong bilingualism and preserved white matter integrity, which might ultimately contribute to the higher level of brain reserve found in these bilingual individuals. A possible explanation holds that continued experience in the maintenance and management of two competing languages enhances and strengthens certain structural pathways in the brain, resulting in a widespread network of white matter connectivity, which then helps protect against natural cognitive decline.
Bialystok, Craik, Fischer, Ware, and Schweizer analyzed and measured brain atrophy in both monolingual and bilingual patients diagnosed with AD using computed tomography (CT) scans with the logic that bilingual patients, when matched with monolingual patients on level of disease severity, should exhibit more atrophy in areas typically used to discriminate between AD patients and healthy ones, as their enhanced cognitive reserve brought about by bilingualism would allow a higher level of functioning than would usually be associated with that level of disease. Results supported this notion and found that the bilingual patients with AD did, in fact, show a greater level of brain atrophy in relevant areas. Even with this increased level of atrophy, however, the bilingual group still performed at the same cognitive level as their monolingual counterparts. These results support the hypothesis maintaining that bilingualism works as a contributor to cognitive reserve and acts as a modifier to behavioral expression that underlies brain atrophy associated with Alzheimer's disease.
Further research supports the above hypothesis, and extends it claiming that bilingualism can postpone the onset of the symptoms of AD by as much as 4–5 years. Bialystok, Craik, and Freedman collected data from bilingual and monolingual patients diagnosed with probable Alzheimer's disease regarding, most importantly, age of onset of cognitive impairment and language history and abilities. A 4.3 year delay in diagnosis and a 5.1 year delay in the reported onset of symptoms was found for the bilinguals in comparison to the monolinguals. Not only do these data support the notion of bilingualism contributing to cognitive reserve, thereby compensating for higher levels of brain atrophy, but also that bilingualism might even postpone the onset of AD symptoms by a dramatic 4–5 years.
On June 30, 2016, Bialystok was named an Officer of the Order of Canada by Governor General David Johnston for "her contributions to our understanding of the cognitive benefits of bilingualism and for opening up new avenues of research in her field".
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