Babies are not blank slates. They come with a lot of pre-programming that is awaiting activation. A great example of this is language. Newborn babies are born with the innate skills needed to pick out words from language, a new study published in Developmental Science reveals.
Before infants can learn words, they must identify those words in continuous speech. Yet, the speech signal lacks obvious boundary markers, which poses a potential problem for language acquisition.
Studies have found that by the middle of the first year, infants seem to have solved this problem, but it is unknown if segmentation abilities are present from birth, or if they only emerge after sufficient language exposure and/or brain maturation.
An international team of researchers from the University of Liverpool, SISSA in Italy, the Neurospin Centre in France and The University of Manchester conducted experiments to find the cues crucial for the segmentation of human speech. The researchers played the infants a three-and-a-half minute audio clip in which four meaningless words, were buried in a stream of syllables. Using a painless technique called Near-Infrared Spectroscopy, which shines red light into the brain, they were able to measure how much was absorbed, telling them which parts of the brain were active.
The researchers discovered two mechanisms in three-day-old infants, which give them the skills to pick out words in a stream of sounds. The first mechanism is known as prosody, the melody of language, allow us to recognise when a word starts and stops. The second is called the statistics of language, which describes how we compute the frequency of when sounds in a word come together. The discovery provides a key insight into a first step to learning language.
Dr Alissa Ferry, University of Manchester, said: "We think this study highlights how sentient newborn babies really are and how much information they are absorbing. That's quite important for new parents and gives them some insight into how their baby is listening to them."
Dr Perrine Brusini, University of Liverpool, said: "We then had the infants listen to individual words and found that their brains responded differently to the words that they heard than to slightly different words. "This showed that even from birth infants can pick out individual words from language."
Dr Ana Flò, Neurospin, said: "Language in incredibly complicated and this study is about understanding how infants try to make sense of it when they first hear it. We often think of language as being made up of words, but words often blur together when we talk. So one of the first steps to learn language is to pick out the words.
"Our study shows that at just three days old, without understanding what it means, they are able pick out individual words from speech. And we have identified two important tools that we are almost certainly born with, that gives them the ability to do this."
The study was funded by the European Research Council.
Materials provided by University of Liverpool.
Ana Fló, Perrine Brusini, Francesco Macagno, Marina Nespor, Jacques Mehler, Alissa L. Ferry. Newborns are sensitive to multiple cues for word segmentation in continuous speech. Developmental Science, 2019; e12802 DOI: 10.1111/desc.12802