Science
Notebook
Monday, June 14, 2004; Page A07
Bilingualism's Brain Benefits
Bilingual speakers are better able to deal with distractions than those who speak only a single language, and that may help offset age-related declines in mental performance, researchers say.
In studies conducted in Canada, India and Hong Kong, psychologists determined that individuals who spoke two languages with equal proficiency and used both equally did better than monolingual volunteers on tests that measured how quickly they could perform while distracted.
"The bilingual advantage was greater for older participants," the researchers wrote yesterday in the journal Psychology and Aging, adding that "bilingualism appears to offset age-related losses" in certain mental processes.
Researchers used the Simon task, a test used to measure mental abilities that are known to decline with age. Test takers saw a red or a blue square flash on a computer screen and were told to depress one or the other of the two "shift" keys depending on which color appeared. As previous research has found, performance slowed when the colored squares moved from their original positions.
Three experiments showed that bilingual speakers of Cantonese and English, Tamil and English or French and English consistently outperformed English-only speakers, said the researchers at York University and the Rotman Research Institute in Toronto, and Dalhousie University in Halifax, Nova Scotia.
The team, led by Ellen Bialystok at York University, hypothesized that the ability to hold two languages in the mind at the same time, without allowing words and grammar from one to slip into the other, might account for the greater control needed to perform well on the Simon task. An alternate hypothesis is that bilinguals have superior working memories for storing and processing information.
-- Shankar Vedantam
Feelings Toward Grandparents
Genes may influence how close a grandchild feels toward a grandparent, according to new research.
William von Hippel of the University of New South Wales in Australia and colleagues hypothesized that grandparents tended to invest more time and emotional energy in grandchildren who were most likely to be their genetic offspring. The possibility of infidelity, for example, means that a grandparent would be more confident that a daughter's children were truly genetic kin than a son's.
"A maternal grandmother knows with certainty that her genetic material is passed to her grandchildren through her daughter, but a paternal grandfather has a double uncertainty -- he has no certainty that either his son or his grandchildren bear his genetic material," von Hippel said.
To test the theory, von Hippel and his colleagues asked 787 university students to rate their emotional closeness to each biological grandparent. In a paper being published in the journal Personality and Social Psychology Bulletin, the researchers report that, indeed, the participants tended to feel closest to their mothers' mothers, followed by their mothers' fathers, then their fathers' mothers, and finally their fathers' fathers.
This was only true, however, when the paternal grandmother had other grandchildren through a daughter, making those grandchildren genetically more certain. When paternal grandmothers had grandchildren only through a son, the degree of closeness was equal to that of maternal grandfathers, researchers found.
"Grandparents must spread their time and resources across grandchildren, and genetic certainty clearly influences this," von Hippel said.
-- Rob Stein
Bison Domestication Soars
The number of bison raised commercially has soared in recent years and totaled 231,950 animals in 2002, the Department of Agriculture said last week in announcing its first-ever census.
They dwarf the number of wild buffalo, which is between 15,000 and 16,000. Before the Europeans settled the West, buffalo numbered between 20 million and 30 million. The only remaining free-roaming herd, which is 3,800 strong, lives in Yellowstone National Park, said Josh Osher, coordinator for the Buffalo Field Campaign. Their numbers are controlled because of the limited habitat available.
According to the USDA, bison are being produced in 4,132 operations across the country. South Dakota is the leading buffalo-producing state, with 40,168 bison.
The last accurate tally of domesticated bison was conducted by the University of Wyoming in 1997, which counted 138,000.
Dave Carter, executive director of the National Bison Association, said that "ranchers try to keep them as genetically pure as possible," though some have been bred with cattle.
Osher said he "hates to see a lot of domestication of a wild animal," but added that he preferred to see buffalo being raised, rather than cows, because "they're better for the landscape, in terms of grazing."
Being bilingual 'protects brain' |
The findings are based on tests on 104 people | Being fluent in two languages may help to keep the brain sharper for longer, a study suggests.
Researchers from York University in Canada carried out tests on 104 people between the ages of 30 and 88.
They found that those who were fluent in two languages rather than just one were sharper mentally.
Writing in the journal of Psychology and Ageing, they said being bilingual may protect against mental decline in old age.
Previous studies have shown that keeping the brain active can protect against senile dementia.
Research has shown that people who play musical instruments, dance or read regularly may be less likely to develop the condition.
Other activities like doing crosswords or playing board games may also help.
Language skills
This latest study appears to back up the theory that language skills also have a protective effect.
Dr Ellen Bialystok and colleagues at York University assessed the cognitive skills of all those involved in the study using a variety of widely recognised tests.
They tested their vocabulary skills, their non-verbal reasoning ability and their reaction time.
Half of the volunteers came from Canada and spoke only English. The other half came from India and were fluent in both English and Tamil.
The volunteers had similar backgrounds in the sense that they were all educated to degree level and were all middle class.
The researchers found that the people who were fluent in English and Tamil responded faster than those who were fluent in just English. This applied to all age groups.
The researchers also found that the bilingual volunteers were much less likely to suffer from the mental decline associated with old age.
"The bilinguals were more efficient at all ages tested and showed a slower rate of decline for some processes with aging," they said.
"It appears...that bilingualism helps to offset age-related losses."
The UK's Alzheimer's Society welcomed the study.
"These findings, that early development of second language may improve a specific aspect of cognitive function in later life, are very interesting," said Professor Clive Ballard, its director of research.
"It is a possibility that the acquisition of a second language in early childhood may influence the process of the development of neuronal circuits.
"However, the results of this particular study need to be interpreted cautiously as they were comparing groups of individual of different nationalities, educated in different systems.
"It is also well recognised that education in general can bestow benefits on cognitive function in later life." |