Newborn babies remember vowels better than consonants

Even newborn babies just a few days old can remember words, although they're better at remembering the vowels in those words than the consonants, say Italian scientists.

Led by Jacques Mehler at the International School for Advanced Studies (SISSA) in Trieste, the scientists used functional NIR spectroscopy to record brain activity in babies between one and four days old when presented with word-sounds comprising four-letter collections of repeated vowels and consonants. Functional NIR spectroscopy works by monitoring the increase in blood flow to active parts of the brain, as reflected in increased levels of oxygenated haemoglobin (oxyhaemoglobin).

In earlier research, the scientists had found that levels of oxyhaemoglobin decreased when newborns were presented with familiar word-sounds, but increased when they were presented with novel word-sounds. In this research, they presented the newborns with either the word-sounds “lili” or “mimi”, waited two minutes and then tested the newborns with word-sounds that differed either in the vowels or consonants. So if initially presented with “mimi”, they were tested with either “mama” or “sisi”.

As they report in a paper in the Proceedings of the National Academy of Sciences, Mehler and his colleagues found that oxyhaemoglobin levels decreased when the newborns were tested with word-sounds containing the same vowels but novel consonants and increased when tested with word-sounds containing the same consonants but novel vowels, indicating that newborns are better at recognising vowels than consonants. Furthermore, these changes in oxyhaemoglobin levels occurred primarily in the right frontal regions of the newborns' brains, which is where verbal memory is housed in adults.

“Basically, these experiments show two things: first of all, in newborns the information conveyed by vowels seems to be much easier to recognize than the information conveyed by consonants,” explains team member Marina Nespor, also at SISSA. “The second important remark is that the frontal areas seem to be involved in the recognition of spoken sequences ever since the very first developmental stages.”