AN INCREASE in the size of the spinal cord may be the key to discovering when
our ancestors developed language, says a British evolutionary biologist.
Anthropologists believe that early hominids鈥攊ncluding Homo ergaster,
which lived in Africa about 1.6 million years ago鈥攄id not use language.
Ann MacLarnon of the Roehampton Institute in London told a conference in London
last week that fossil remains of H. ergaster have narrow canals in the thoracic
vertebrae of the ribcage much like today鈥檚 nonhuman primates.
Early humans (Homo sapiens) of 100 000 years ago, who are thought to have
used speech, have canals that are visibly wider, MacLarnon says. She believes
that the increased space accommodates the extra spinal cord needed to fine-tune
breathing control, which is vital for speech. 鈥淵ou can鈥檛 have fully human speech
without it,鈥� she says. 鈥淓arly hominids would have been capable of only short,
slow, unmodulated speech patterns.鈥�
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The physical attributes needed for speech have been largely overlooked in the
search for its origins, MacLarnon says. She hopes the new result will help
anthropologists to home in on the time that speech developed. Fossil vertebrae
are rare, and MacLarnon can only estimate when speech arose to the nearest
million years. She hopes future finds will narrow it down.