The Washington Post
March 4, 2005 Friday
Final Edition
SECTION: A Section; A10
LENGTH: 776 words
HEADLINE: Advanced Brain Is Cited in Fossil;
Researchers Say Findings Point to Unique Human Species
BYLINE: Guy Gugliotta, Washington Post Staff Writer
BODY:
It's not the size of the brain that matters. It's the way it's
arranged. That's the conclusion of researchers studying the skull of
a tiny, Hobbit-like human ancestor who lived on a remote Indonesian
island 18,000 years ago.
Researchers are reporting today that the grapefruit-size brain had
sophisticated characteristics found only in modern humans. They said
the findings offer further evidence that the tiny hunter discovered
last year was a unique archaic species that coexisted with modern
humans long after other primitive ancestors died out.
"It's remarkable," said Florida State University paleoneurologist
Dean Falk, leader of the team that studied the skull. "I thought we
were going to be looking at a chimpanzee skull, but this has advanced
features that I've not seen in anything this size."
Falk's study, published in the journal Science, was conducted at the
behest of the National Geographic Society and with the collaboration
of the Australian-led team that found the fossil. The new research,
however, failed to still skeptics who have dismissed the finding as a
pygmylike modern human, or a modern human with a deformity known as
microcephaly -- a small head and brain.
The tools and artifacts found with the skull "were made by [fully
competent] modern humans," said paleoanthropologist James Phillips of
the University of Illinois and Chicago's Field Museum in a phone
interview. "This individual could not mentally have made them."
The fossil was discovered in a limestone cave on Indonesia's Flores
Island. It lies immediately east of the "Wallace Line," which divides
islands that once were connected to Australia and Asia and those, such
as Flores, that remained isolated for millions of years.
The team, led by Michael J. Morwood of Australia's University of New
England, estimated the fossil was 18,000 years old, meaning it had
survived long after modern humans appeared 150,000 years ago and well
after the extinction 30,000 years ago of Neanderthals, the last known
archaic human.
The team suggested that the fossil exemplified the "island rule":
that isolated islands with limited resources and no natural predators
cause large animals to get smaller, while small animals get larger.
Prehistoric Flores had miniature elephants and giant Komodo dragons.
The team found remains of seven tiny people, including the nearly
complete skull of a 30-year-old woman. They dubbed the fossils Homo
floresiensis, which quickly acquired the nickname Hobbit after the
diminutive characters in author J.R.R. Tolkien's fantasies.
What astounded anthropologists, however, were the sophisticated stone
points and barbs found with the remains. Evolutionary orthodoxy holds
that advances in human skills -- such as tool-making -- come with
increases in brain size, and such weapons had never appeared before
the advent of modern humans.
The Hobbit, by contrast, had a 25 cubic-inch brain -- comparable to
primitive human ancestors who lived 2.5 million to 3 million years
ago. "It was shocking," said Rick Potts, director of the Smithsonian
Institution's Human Origins Program, in a telephone interview. "When
you thought about it, you realized that [island adaptation] had
happened to other mammals, but I was a doubter."
Falk, working with colleagues at Washington University's medical
center, in St. Louis, and the Australian discovery team, made
"endocasts" of the inside of the fossil skull and built electronic
and plastic mock-ups of the brain. Then her team compared them with
those of modern humans, chimpanzees, a human ancestor common in
Indonesia and a microcephalic individual from Europe.
Falk found that the brain's general shape most closely resembled the
human ancestor, Homo erectus, albeit much smaller. But she also found
outsize temporal lobes along its sides -- a characteristic of modern
humans.
The Hobbit's frontal lobe was also highly convoluted, another
characteristic of modern humans. All this "just blew me away," Falk
said in a telephone interview. "The message is that it's its own
creature with a suite of features that are unique."
The tests showed that the fossil had little in common with the
microcephalic specimen, but Field Museum primatologist Robert Martin,
a leading skeptic, said testing against a single sample proved
nothing. "They don't even tell you if [the microcephalic] was an
adult," Martin said in a phone interview. "I'm suggesting the Flores
discovery is a pathology, and I'm surprised they would publish this
with such limited information."
Falk said that the microcephalic skull "was typical . . . and we are
confident that [the Hobbit skull] is not a true microcephalic."
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