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Songbirds, parrots, and hummingbirds – birds
that learn complex, repetitive songs – have provided insights
about the origin of syntax, the elements that dictate human speech.
Learning of songs or calls in the animal kingdom is
rare. Most animals rely on innate (inborn) information for their
vocal communications. Overall, only 3 groups of birds (parrots,
hummingbirds, and songbirds) and three groups of mammals –
humans, bats, and cetaceans (whales and dolphins) – are capable
of vocal learning, which is regarded as the essential first step
in the evolution of human language.
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A team of researchers led by Erich Jarvis of Duke
University in North Carolina has found the key regions of a bird
brain that enable it to construct and remember the complicated sequences
of sounds that make up bird songs.
Dr. Jarvis said his team’s work on parrots, hummingbirds,
and songbirds led to the identification of circuits in the brain's
cerebrum called glutamate receptors, which help to transmit nerve
impulses, and grow new nerve connections when the brain is learning
a song.
Even though hummingbirds have some of the smallest
brains of vertebrates, they are still capable of learning and remembering
extraordinarily complex songs.
The primary reason for hummingbirds’ vocal specializations
is to defend territories and attract mates, said Dr. Jarvis, adding
“the more complex the syntax, the sexier the song."
"Although it might seem far- fetched, I would not be surprised
if these ancient receptors could some day help us to identify the
entire system of brain regions used for vocal learning and language
in humans in a way that has not been done before," Dr. Jarvis
said.
If it is true that these receptors can be used to
identify the human language areas, one of many implications of this
new information is that it will help surgeons to localize these
brain areas during surgery, allowing them to avoid them.
The above information was gleaned from the article, “Birds
that sing complex songs give clue to origins of human syntax,”
by Steve Connor, Science Editor published on the February 17, 2002
at http://news.independent.co.uk/world/science_medical/story.jsp?story=379048
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