The hobbit-sized hominid found on the Indonesian island of Flores last October may have been smarter than initially imagined. New research suggests its brain could perform advanced cognitive tasks--a finding that may overturn long-held ideas about human evolution. The results also suggest that the creature truly is a new hominid species rather than a modern human with an abnormally small head, as some had speculated.
When the 18,000-year-old bones of Homo floresiensis were first unearthed, they presented a paradox: Despite having a brain no larger than a chimp's, the approximately 1-meter-tall hominid showed signs of advanced intelligence, including hunting with sophisticated stone tools.
To resolve the paradox, Dean Falk of Florida State University in Tallahassee and colleagues analyzed an endocast, which preserves the surface features of the brain. For comparison, the researchers also examined various endocasts of the skulls of a microcephalic human, a pygmy, primates, and other modern humans and extinct hominids. They found that, relative to its overall size, the brain of H. floresiensis had very large temporal lobes, which are associated with understanding speech and hearing. Even more dramatically, the hominid had highly folded and convoluted frontal lobes, which are implicated in higher cognition. "I haven't seen swellings like this before in any [extinct] hominid endocasts," including those of H. erectus, Falk says.
The findings, published online today by Science, suggest that the little Flores people may have created the stone tools that were found near them, which are more typical of those made by prehistoric modern humans than earlier hominids including H. erectus. Falk also says the results argue against the notion that the creature was microcephalic: "The skull is totally the wrong shape."
"The real take-home message here is that advanced behaviors, like making sophisticated stone tools, do not necessarily require a large, modern, humanlike brain," says evolutionary anatomist Fred Spoor of University College London. But not everyone agrees. Anthropologist Katerina Semendeferi of the University of California, San Diego, cautions that "many would argue that absolute size is of paramount importance;" she adds that stronger evidence linking the stone tools with the small Flores people would strengthen the case for their cognitive abilities.