Even though they can't remember a word in mandarin, children from China adopted in France bear the same brain activity response as bilinguals. Essentially, their brains use the same patterns and neural areas as bilinguals even though by all accounts they must think they're monolingual. The implies that the impact of early developmental experiences on later neural outcomes is much more significant than some might think.
When I was three or four years old, I think, I would watch some silly cartoons every morning for about two hours on TV. These cartoons were dubbed in Italian, and in a matter of months I become quite proficient, my parents told me. This lasted for half a year, then I stopped watching the Italian station and moved to something different. Cartoon Network, if I recall, became a lot more interesting for me. Nevertheless, by the time I was six I had forgotten every Italian I knew, even though I could actually have a conversation (and had with a native speaker!) less than a year before. To this day, the only word in Italian I know is "pizza".
This short story might be familiar to most of you, its essence I mean. We all have episodes in our early childhood when we could speak words in a different language, play a weird game or knew a certain skill that now's oblivious like a black hole. Episodes from a time when we, as children, had sponges for brains, rapidly soaking information, but just as easily squeezing it out of the system. But is that information really lost? Maybe, but the brain connections that formed in this key period are likely more resilient, as illustrated by the study made by researchers at McGill University, Canada.
The team performed fMRI scans on three sets of children: (1) monolingual French children; (2) children adopted from China before age 3 who discontinued Chinese and spoke only French; (3) Chinese-speaking children who learned French as a second language but maintained Chinese. The scans were made while the children performed a French phonological working memory (PWM) task. In other words, the children were played French sounding words. Strikingly, the adoptees who considered French as their only language showed a brain activation pattern more resembling that of Chinese-French bilinguals than those of the French-only speakers as they recruited more than one brain area. Early exposure to a language, the findings suggest, build strong brain connections that may last for a lifetime.
Scientists aren't sure why bilinguals need to recruit more brain areas when they speak their second language, but there are some evidence that being bilingual comes with certain cognitive benefits. Bilinguals get distract less easily, are better at multitasking, find creative solutions to problems more often, have increased memory capacity, and lower risk of Alzheimer's.