Regularly hearing two languages linked to mental advantage by age 6 months
Neurocognitive Development Lab/Singapore Inst. for Clinical Sciences
Months before starting to talk, babies receive a thought-provoking gift from the gab heard in bilingual homes.
By age 6 months, infants raised in bilingual households display a basic learning and memory advantage over tykes in one-tongue homes, say psychologist Leher Singh of the National University of Singapore and her colleagues. Hearing two languages early in life enhances babies’ ability to handle new information, a general mental skill that may contribute not only to bilingual fluency but to other types of distinctions, such as recognizing categories of objects, the scientists report July 30 in Child Development.
“Our finding of a bilingual advantage on a visual task that does not involve processing speech or sounds suggests that there are fundamental cognitive benefits associated with early exposure to two languages,” Singh says.
Previous studies have found that, compared to infants exposed to one language, babies in bilingual families adjust better to simple, grammar-like conditioning rules. They also are superior at perceiving pitches and sound durations in a language they’ve never heard before. But it had been unclear whether the advantages enjoyed by bilingual babies include mental abilities with no direct bearing on speech, says psychologist Ellen Bialystok of York University in Toronto, who did not participate in the new study.
“My preferred interpretation, consistent with the new data, is that early bilingual environments enhance the development of visual attention, and attention may be crucial to cognitive performance,” Bialystok says.
Singh’s team studied 114 children, all 6 months old and residents of Singapore. Parents of 54 infants spoke only English, Mandarin, Malay or one of two Indian languages. Parents of the rest spoke both English and another language. During the experiment, the children sat on a parent’s lap as a beeping blue and white ball drew their attention to an image of a stuffed bear or wolf on a computer monitor. These play animals looked superficially similar but differed in features such as fur color and eye sizes. Within 20 trials, the time that 108 babies spent looking at the toy declined sharply, a response psychologists call visual habituation, representing the children’s familiarity with the sight. The remaining six kids were dropped from the study.
Infants from bilingual families showed larger and quicker drops in the time spent looking at the toy than did those from one-language families.
When shown the original stuffed bear or wolf next to the other, previously unseen toy for 10 seconds in each of two further trials, babies with bilingual backgrounds looked at the novel toy for an average of 7.4 seconds, versus 6 seconds for the single-language group. That difference was unlikely to occur by chance, Singh’s group estimates.
Together, the results suggest two things, Singh says: Babies in the bilingual group had the upper hand in forming memories of objects and in recognizing an item as new to them.
Further research is needed to confirm mental advantages for babies with exposure to two languages, she cautions. One testable possibility is that babies who hear accents in two languages better understand accented speech, and perhaps even unfamiliar speakers, later in life, Singh says.
L. Singh et al. Back to basics: A bilingual advantage in infant visual habituation. Child Development. Published online July 30, 2014. doi:10.1111/cdev.12271.
L. Sanders. Babies’ brains practice words long before they can speak. Science News Online, July 23, 2014.