Two-week-old babies seem able to distinguish the rhythm and other sounds of a nursery rhyme they heard in the uterus from an unfamiliar one. The extent to which they can do this appears to predict their language development, which could open up a new way of identifying babies at risk of language-related conditions in later life.
Language learning is thought to begin before birth, with research showing newborns can and can tell their based on the rhythm of speech.
A 2013 study suggested that newborns and 4-month-old babies could . But it was unclear whether the infants were remembering the melody, the lyrics, the rhythm or all three.
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To get a clearer picture, at the University of Salzburg in Austria and her colleagues recruited 60 pregnant women and randomly assigned them to two groups. Each group was asked to play recordings of one of two German nursery rhymes to their abdomen twice a day from the 34th week of pregnancy onwards. Both the nursery rhymes were spoken, with no tune.
The researchers also created altered versions of the nursery rhymes by changing their rhythm,聽reversing them and removing high-frequency sounds.
Two weeks after the women gave birth, the researchers played both nursery rhymes to the babies while using electroencephalography to measure electrical activity in their brains. This indicated whether they were familiar with the rhymes and how easily they could pay attention to them.
The team found that the original versions of the familiar nursery rhymes seemed easiest for the babies to follow. In contrast, the unfamiliar nursery rhymes elicited a stronger electrical activity response, suggesting that the infants exerted more cognitive effort when listening to them.
The researchers also played the altered nursery rhymes, finding that they were harder for the babies to follow than the unmodified ones, further suggesting that they could discriminate between the recordings and that it isn鈥檛 just the sung melodies of some nursery rhymes that such infants recognise.
Overall, the study shows that 鈥渂abies can tell familiar rhymes apart, emphasising how important the rhythm and tone of speech are for them to learn language early on鈥�, says at Oxford Brookes University in the UK. 鈥淚t also shows that, while in the womb, babies pay close attention to the sounds they hear [and] adds to the evidence showing that prosody 鈥� the rhythm, stress and intonation of language 鈥� plays a big role in how babies process language.鈥�
The researchers followed up the infants when they were 6 months old, finding that the extent to which their language abilities had developed correlated with how well they tracked the nursery rhymes at 2 weeks old.
With further investigation, neural speech tracking soon after birth could be used to identify those at risk of developmental language conditions, the researchers write in their paper.
鈥淚t鈥檚 very hard to reliably evaluate the language development of a preverbal child, and with a newborn, it is practically impossible, [but] neural tracking methods could evaluate children from birth, make a prognosis or help in recommending therapies,鈥� says Florea. 鈥淲e are not there yet, but this correlation with later development is the first step.鈥�
bioRxiv
