Updating Magic Universe
It really is your mother tongue
Amid all the politically correct attempts to minimize the differences between the sexes, and ignore their contrasting roles in child rearing, how refreshing to see knock-down evidence pointing the other way! In results released today, researchers in Japan proclaim the special role of mothers in evolution’s most distinctive task for Homo sapiens – encouraging babies to chat.
The tale is quickly told because the RIKEN Brain Science Institute (located near Tokyo) has provided helpful diagrams. I’ve re-written the captions.
Special brain activity in mothers with babies at the babbling, pre-verbal stage appears in functional magnetic resonance imaging (fMRI) when they hear maternal baby-talk, technically known as infant-directed speech (IDS). The highest activity, denoted in red, is in the key language areas of the left hemisphere, Broca’s and Wernicke’s. Other women show a slightly raised response, but men don’t, whether they are fathers or not.
The most amusing technical detail is that the investigators wanted to image the brains of mothers actually interacting with their babies, but they couldn’t. It was impossible for the mothers to keep their heads still. Listening passively to playbacks of baby-talk had to do instead. The experimental subjects were 35 first-time parents with pre-verbal infants, 30 men and women without any parenting experience, 16 mothers with toddlers who spoke two-word utterances and 18 mothers with children in elementary school.
I wrote at length about language acquisition in The Human Conspiracy, but that book is out of print so I include here only a cartoon from it. To add a couple of sentences as an update for Magic Universe, there are relevant stories about “Speech” and “Grammar”. Maybe I’ll find a better place for the update later, but oddly enough I’m most explicit about the role of mothers when recalling a classic study by the socio-linguist William Labov about how local dialects evolve. That’s in my story “Languages: why women often set the new fashions in speaking”.
Passage in Magic Universe
In 1970 Labov moved to the University of Pennsylvania. In Philadelphia he found vowel sounds engaged in a complicated game of musical chairs, between different classes and ethnic groups in the city. He and a growing throng of students and emulators also roamed with their tape recorders around the world, to Belfast with its sharp Catholic-Protestant divide, for example, and to Papua New Guinea, which was trying to forge a national language in a country with hundreds of different local tongues.
Labov’s working hypothesis, as he articulated it in 1975, was that people change their language because it is an expressive symbol of local identity. ‘In every case that we’ve studied,’ he said, ‘the most advanced sound changes are found among those groups whose local status is being challenged by other groups moving in from outside. Sound change is one way of reasserting local identity against that challenge.’
In the ensuing decades, sociolinguistics acquired a mathematical precision rarely known in studies of observable social behaviour. You could measure the degree and rate of local language evolution. You could track the geographical diffusion of a change to surrounding areas, and follow its adoption through time, from one generation to the next.
A salient discovery was the role of women in driving the changes in dialects. Martha’s Vineyard, where young men set the trend, turned out to be unusual in that regard. In most cases a new variant in a speech sound is detected first in women of childbearing age, and then in their children. Elderly men may be the last to change, if they do so at all.
There is no mystery about the mechanism, because most people learn their mother tongue literally from their mothers or from female carers. An uncanny parallel with the spread of fashions in clothing and cosmetics might imply a certain feminine whimsicality. But given the manifest links to real social forces, and the importance of dialect to the children’s and grandchildren’s sense of social identity, it is unlikely that linguistic changes are frivolous.
(The story continues with Labov later doubting if his working hypothesis was adequate to explain the widespread reach of sound changes, never mind the evolution of 5000 different languages worldwide.)
Updating the last paragraph quoted
There is no mystery about the mechanism, because most people learn their mother tongue literally from their mothers or from female carers. Astounding evidence about that was to emerge from the RIKEN Brain Research Institute in Japan, in 2010. This was the discovery using brain scans that key areas of a mother’s brain switch to a special mode of activity for generating baby-talk when her infant is about six months old.
Returning to Labov’s emergent local dialects, an uncanny parallel with the spread of fashions …
Yoshi-Taka Matsuda, Kenichi Ueno, R. Allen Waggoner, Donna Erickson, Yoko Shimura, KeijiTanaka, Kang Cheng and Reiko Mazuka. “Processing of infant-directed speech by adults,” Neuroimage (2010). doi:10.1016/j.neuroimage.2010.07.072
RIKEN press release 10 August 2010 available at http://www.alphagalileo.org/AssetViewer.aspx?AssetId=30623&CultureCode=en
N. Calder, The Human Conspiracy, BBC Publications, 1975.
N. Calder, Magic Universe, p. 446, Oxford UP, 2003