You could say they sent the first tweets. An ancient whistling language that sounds a little like birdsong has been found to use both sides of the brain – challenging the idea that the left side is all important for communicating.
The whistling language is still used by around 10,000 people in the mountains of north-east Turkey, and can carry messages as far as 5 kilometres.
Researchers have now shown that this language involves the brain’s right hemisphere, which was already known to be important for understanding music.
Until recently, it was thought that the task of interpreting language fell largely to the brain’s left hemisphere. Onur Güntürkün of Ruhr University Bochum in Germany wondered whether the musical melodies and frequencies of whistled Turkish might require people to use both sides of their brain to communicate.
His team tested 31 fluent whistlers by playing slightly different spoken or whistled syllables into their left and right ears at the same time, and asking them to say what they heard. The left hemisphere depends slightly more on sounds received by the right ear, and vice versa for the right hemisphere. By comparing the number of times the whistlers reported the syllables that had been played into either their right or left ear, they could tell how often each side of the brain was dominant.
As expected, when the syllables were spoken, the right ear and left hemisphere were dominant 75 per cent of the time. But when syllables were whistled, the split between right and left dominance was about even.
“In all languages, tonal or atonal, click or sign language, written or spoken, it’s so far been the left hemisphere that appears to do most of the interpretation,” says Güntürkün. “Now, we’ve shown for the first time equal contributions from both hemispheres.”
Canary island tweets
He says their results show that the left hemisphere’s importance in understanding language is not as independent from the rest of the brain as was once thought – an idea that has begun to be challenged recently.
“This study uses a remarkable and original paradigm to reinforce arguments that both hemispheres are involved in processing different components of speech,” says Diana Deutsch of the University of California at San Diego.
The results support a 2005 study that used fMRI scans to show that shepherds in the Canary Islands use both hemispheres to interpret a whistled form of Spanish.
“It’s consistent with the idea that the form of a language can influence the brain networks that are recruited to process it,” says Sophie Scott of University College London.
Mobile phone irony
Güntürkün says that if there are any Turkish whistlers who have had a stroke affecting their left hemisphere, he would like to find out if they retain more language ability than non-whistlers. He suspects their right hemispheres might help them compensate.
Whistled Turkish is dying out, however, partly because of mobile phones. “You can gossip with a mobile phone, but you can’t do that with whistling because the whole valley hears,” says Güntürkün.
Journal reference: Current Biology, DOI: 10.1016/j.cub.2015.06.067
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