A new study points out that the experience of hearing two languages may give babies an early learning advantage, even before they can babble a single word.
The study has shown that infants exposed to two languages (bilingual babies) quickly adapt to different learning cues at seven months old compared with babies from single-language households.
The findings may lead researchers to rethink how hearing two languages trains the young brain, even before babies have learned how to formulate words.
This early learning advantage may not necessarily translate into higher intelligence later on in life.
However, it does reveal that babies benefit early on from having bilingual exposure, when they themselves still babble nonsense.
"We believe that the enhancement is due more to perception at this age, rather than [language] production," Live Science quoted Jacques Mehler, a cognitive neuroscientist at the International School for Advanced Studies in Trieste, Italy, as saying.
For the study, Mehler and fellow researcher Agnes Kovacs recruited 'crib bilinguals' from families in the Trieste area of Italy, where parents spoke to infants from birth using both Italian and Slovenian mother tongues.
The researchers taught bilingual and monolingual babies to look at one side of a screen in anticipation of a visual "reward" image of a puppet, after the infants first learned to associate a sound cue with the image.
The visual treat was then switched to the other side of the screen, so that researchers could see how quickly babies would learn to switch their anticipatory look to that other side.
Bilingual babies beat out monolingual babies in three such experiments, even when the sound cues changed from nonsense syllable combinations to a structured sound cue, and then a visual cue. In all three cases, bilingual babies soon learned to switch their anticipatory attention to the other side of the screen, whereas monolingual babies never adapted.
This clearly showed a bilingual baby advantage in thinking that involved so-called executive function, which helps regulate abilities such as being able to start and stop actions.
It also indicated that having early bilingual exposure could train the mind in a more general sense, rather than just a language-specific sense as some researchers had suggested.
The study appears in the April 13 issue of the journal Proceedings of the National Academy of Sciences.