Multilingualism....

[William J Poser]

Here are the reference to the paper referred to in the Science Daily
article and the abstract:

Kave, Gitit, Eyal, Nitza, Shorek, Aviva, and Jiska Cohen-Mansfield (2008)
``Multilingualism and Cognitive State in the Oldest Old,''
Psychology and Aging 23.1.70-78.

In this study, the authors examined whether the number of languages a
person speaks predicts performance on 2 cognitive-screening
tests. Data were drawn from a representative sample of the oldest
Israeli Jewish population (N = 814, M age = 83.0 years; SD = 5.4) that
was interviewed first in 1989 and then twice more within the following
12 years. Cognitive state differed significantly among groups of
self-reported bilingual, trilingual, and multilingual individuals at
each of the 3 interview waves. Regression analyses showed that the
number of languages spoken contributed to the prediction of cognitive
test scores beyond the effect of other demographic variables, such as
age, gender, place of birth, age at immigration, or
education. Multilingualism was also found to be a significant
predictor of cognitive state in a group of individuals who acquired no
formal education at all. Those who reported being most fluent in a
language other than their mother tongue scored higher on average than
did those whose mother tongue was their best language, but the effect
of number of languages on cognitive state was significant in both
groups, with no significant interaction. Results are discussed in the
context of theories of cognitive reserve.