Saturday, November 7, 2009

'Accents' in the womb?

Spectrogram of a male voice saying "tatat...Image via Wikipedia
BBC News ran a story yesterday on babies' ability to pick up certain aspects of their parents' accents in the womb. Before we get carried away by the image of neonates springing out into the world speaking broad Geordie or Brummie, we should look at the study (in press in the journal Current Biology) in a little more detail. The German researchers recorded and analysed the cries of some very young babies—between 2 and 5 days old—born into two language groups, French and German. There were 30 babies in each group. The analysis of the recordings involved examination of the cries' 'melody contours', which makes use of the fact that the cry of a baby follows a distinctive pattern: first rising in pitch, and then falling, in a single arc. 

The results of the analyses showed clear differences between the language groups. The French babies' cries spent longer on the rising part of the arc, and the German cries were skewed towards the falling part. These patterns match up to the particular prosodic patterns of the French and German languages, as demonstrated in other studies (and fully evident to listeners to those spoken languages).

There's nothing particularly new about a finding that foetuses can pick up and learn about auditory information in the womb. In my book, I describe an experiment conducted by Peter Hepper two decades ago, in which babies who had been exposed to the theme tune of the soap Neighbours showed a preference for that tune after they had been born. Plenty of other convincing evidence for foetal learning has been published since the time of Hepper's study. What is striking about this new study is that babies aren't just learning patterns in the womb, but they are also showing an ability to mimic them—which must call for some very sophisticated control over the articulatory system (the system of muscles that allows us to produce speech). Previous findings had shown vocal imitation at 12 weeks, but no earlier. Rather than just making a noise that is constrained by the respiratory (breathing) cycle, newborn babies are actually shaping the sound they make, and doing it in response to sounds they have already heard in the womb. This is particularly true of the French babies, with their 'rising' intonation—not the sort of cry you would hear if babies were simply vocalising their breaths.

In her comments to BBC News, study author Kathleen Wermke speculates that 'crying with an accent' may play a part in attracting the mother's attention and thus forging a bond with her. I was also interested in the comment by Debbie Mills of Bangor University, who questions whether this neonatal capacity for imitation might fall away shortly after birth only to return later in a different form. This 'inverse-U' trajectory of development is commonly observed in the first few months of life, with newborns showing capacities that they then lose, only to recover them again a few months later as different neural systems take responsibility for them.

(Mampe et al., Newborns’ Cry Melody Is Shaped by Their Native Language, Current Biology (2009),
doi:10.1016/j.cub.2009.09.064)

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