In Kuṣköy, a
village in the north-eastern region of Turkey, some inhabitants have
mastered not only
spoken, but also whistled Turkish. © RUB, Güntürkün
Left hemisphere not dominant in the perception of all
languages
Whistled Turkish involves both hemispheres equally
(August 17, 2015) Researchers at the Ruhr-Universität Bochum have debunked the
theory that the left brain hemisphere is dominant in the processing of all languages.
To date, it has been assumed that that dominance is not determined by the
physical structure of a given language. However, the biopsychologists have
demonstrated that both hemispheres are equally involved in the perception of
whistled Turkish. Onur Güntürkün, Monika Güntürkün and Constanze Hahn report in
the journal “Current Biology”.
Common theory: left hemisphere dominant in language
perception
The perception of all spoken languages – including those
with clicks –, written texts and even sign language involves the left brain
hemisphere more strongly than the right one. The right hemisphere, on the other
hand, processes acoustic information via slow frequencies, pitch and melody.
According to the currently commonly held opinion, the asymmetry in language processing
is not determined by the physical properties of a given language. “The theory
can be easily verified by analysing a language which possesses the full range
of physical properties in the perception of which the right brain hemisphere is
specialised,” says Onur Güntürkün. “We can count ourselves lucky that such a
language exists – namely whistled Turkish.”
Hearing test with
spoken and whistled Turkish
The Bochum team tested 31 inhabitants of Kuṣköy, a village
in Turkey, who speak Turkish and whistle it as well. Via headphones, they were
presented either whistled or spoken Turkish syllables. In some test runs, they
heard different syllables in both ears, in other runs the same syllables. They
were asked to state which syllable they had perceived. The left brain
hemisphere processes information from the right ear, the right hemisphere from
the left ear. For spoken Turkish, a clear asymmetry emerged: If the
participants heard different syllables, they perceived the syllables from the
right ear much more frequently – a dominance of the left brain hemisphere. That
asymmetry did not exist in whistled Turkish. “The results have shown that brain
asymmetries occur at a very early signal processing stage,” concludes the
researcher from Bochum.