Why Bilinguals Are SmarterA very interesting article published in The New York Times (March 17, 2012) written by Yudhijit Bhattacharjee.
"The key difference between bilinguals and monolinguals may be more basic: a heightened ability to monitor the environment. “Bilinguals have to switch languages quite often — you may talk to your father in one language and to your mother in another language,” says Albert Costa, a researcher at the University of Pompeu Fabra in Spain. “It requires keeping track of changes around you in the same way that we monitor our surroundings when driving.”
Read the complete article in The New York Times