Apes have same speech area in brain as human

Carrie McLaren carrie at stayfreemagazine.org
Sun Dec 2 14:46:17 EST 2001


The Independent (London)
November 30, 2001, Friday

HEADLINE: APES HAVE SAME SPEECH AREA IN BRAIN AS HUMANS

BYLINE: Steve Connor Although apes communicate by grunts and 
gestures, they possess a brain component that is also critical for 
human speech Rex

BODY:

GORILLAS AND chimpanzees possess a rudimentary speech centre within 
their brains that until now was thought to be unique to humans, 
scientists have found.

Brain scans of the apes - man's closest living relatives - have 
revealed a small, lopsided structure buried in the front part of the 
head which in humans is critical for language.

The structure, Brodmann's area 44, is part of the language centre 
known as Broca's area, and the scans reveal that it is larger and 
more developed in the left half of the ape's brain than in the right 
hemisphere - just as it is in humans. Claudio Cantalupo and William 
Hopkins, who conducted the study at the Yerkes Primate Research 
Centre at Emory University in Atlanta, Georgia, were surprised such a 
critical feature within the ape's brain had gone unnoticed.

Unlike humans, apes do not have language, and communicate by grunts 
and hand movements. The scientists believe their brains show that the 
evolution of language is rooted in a common ape-human ancestor who 
lived more than five million years ago.

Mr Cantalupo and Mr Hopkins say in the journal Nature: "The part 
possession by great apes of a homologue of Broca's area is puzzling, 
particularly considering the discrepancy between sophisticated human 
speech and the primitive vocalisations of great apes."

Chimpanzees and gorillas nevertheless share one thing in common with 
human communication - they tend to use their right hands when 
grunting, which are controlled by the left-side of the brain.

"Our findings suggest that the neuro-anatomical substrates for 
left-hemisphere dominance in speech production were evident at least 
five million years ago and are not unique to hominid evolution," the 
scientists say. "Whatever the function of area 44 in great apes, our 
finding that these species show a human-like asymmetry ... indicates 
that the origin of asymmetry in language-related areas of the human 
brain should be interpreted in evolutionary terms rather than being 
confined to the human species."

The latest study follows work published in 1999 showing that wild 
chimpanzees have a relatively sophisticated culture in which they are 
able to pass on ideas and inventions to their offspring through 
teaching and learning.

Other studies at Georgia University's Language Research Centre have 
indicated that some chimpanzees can understand simple English 
sentences. Panbanisha, a hand-reared female pygmy chimpanzee, can 
communicate in basic phrases using a keyboard and a computer screen 
displaying symbols that she can press to produce a rudimentary 
response to a human voice.




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