| 8 April 2009
Hobbit brain was organized for complex intelligence
An analysis of the inner surface of an 18,000-year-old skull assigned to Homo floresiensis, a species also known as hobbits, indicates that this tiny individual possessed a brain blessed with souped-up intellectual capacities needed for activities such as making stone tools, says anthropologist Dean Falk of Florida State University in Tallahassee. Even as H. floresiensis evolved a relatively diminutive brain, the species underwent substantial neural reorganization that allowed its members to think much like people do, Falk contended.
She compared a cast of the cranium's inner surface, or endocast, obtained from the partial hobbit skeleton LB1 to endocasts from both modern humans and from other fossil skulls in the human evolutionary family, called hominids for short. These casts bring into relief impressions made by various anatomical landmarks on the brain's surface. "LB1 reveals that significant cortical reorganization was sustained in ape-sized brains of at least one hominid species," Falk said. Evidence has shown that some hominid species experienced marked increases in brain size over time, but that neural reorganization took center stage for others, including hobbits, she proposes. Currently, no one knows whether a large-bodied or small-bodied species gave rise to hobbits, whose fossils have been found on the Indonesian island of Flores.
Although small in size, LB1's endocast displays a humanlike shape, Falk asserted. An endocast from Australopithecus africanus, a roughly 3-million-year-old South African hominid species, looks similar to that of LB1, Falk asserted. Yet unlike the earlier A. africanus, LB1 possessed a set of brain features that other researchers have implicated in complex forms of thinking by people today, she said. These features ran from the back to the front of the brain. Traits such as expanded frontal lobes and enlarged regions devoted to integrating information from disparate areas would have supported creative and innovative thinking, in Falk's view. No signs of disease or abnormal development appear on LB1's brain surface, she noted. Some researchers argue that the specimen came from a modern human who had some type of growth disorder.
Hobbit-fueled controversy remains strong, though. In another meeting presentation, anthropologist Robert Eckhardt of Pennsylvania State University in University Park reported that the height range within a foraging group of people now living on the hobbits' Indonesian island overlaps with height estimates for LB1. Eckhardt and his colleagues argue that, given this similarity to people today, LB1 can't be assigned to a new species.
Source: ScienceNews (3 April 2009)
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