Humans can be distinguished from other apes in many ways, such as our general hairlessness, our upright biped, and, of course, our powerful brain. But it turns out that our cognitive ability didn’t evolve as early as previously thought, according to new research by an international team of researchers.
The team’s findings, published today in the journal Science, are based on five 1.8-million-year-old skulls from an area of about 10 hectares near the Georgian town of Dmanisi. The brains of these early arrivals in Europe and Asia—Hominin species that evolved long before homo sapienswere already known to be small, but at the recent inspection the researchers made endocasts from the old skulls. In fact, they created topographic maps of the brain cases, which can reveal minute differences in shape that provide insight into the development of different regions of the long-decomposed brain. Understanding ancient brain structures helps shape the genesis of our species; whether we were step-by-step or sprinting towards our modern morphology and which way we took to get here.
“These structures are extremely interesting because they provide the neural substrate for complex cognitive tasks such as tool creation and use, social cognition and especially spoken language,” said authors Marcia Ponce de León and Christoph Zollikofer, both paleoanthropologists at the University of London. Zurich, in an email. “We don’t know if these hominids had language in the modern sense, but the brain structures were there and probably evolved along with language skills.”
The story of human origins is clouded by a fragmentary fossil record, like an old book so worn out in time that only a few handfuls of sentences are used to guess the whole story. But think we do, and our accuracy gets better with every newfound fossil and newly invented technology to analyze them. The skulls examined in the new newspaper were excavated between 1991 and 2008 and are housed in the Georgian National Museum in Tbilisi.
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Compare the Georgian Homo endocasts to ones taken againm skulls about the same age and younger from Africa and the Indonesian island of Java, The team found that the brains of the Georgian great apes were more like that of great apes than modern humans. This suggests that modern brain structures emerged from Africa at least 100,000 years later than early wanderers who left the continent.
“There must have been two ‘out-of-Africa’ spreads in the beginning Homo: the first is documented by the fossil evidence from the site of Dmanisi in present-day Georgia ”about 2 million years ago, the researchers said in their email. “This one Homo populations had primitive brains. The second distribution is documented by the fossils from Java; these populations had modern brains. “
Since the earliest fossil attributed to the genus Homo Dating back to nearly 3 million years ago, the Georgian skulls indicate at least some of the earliest humans lacked the developed brain that we normally think of as definiof our lineage. It was a moment, the investigators said, of “realizing that the emperor had no clothes”, the clothes here be a reorganized brain.
The researchers were particularly interested in the frontal lobes of the Dmanisi individuals, an area of the brain that likely played a vital role in the early human endeavors of language development and toolmaking. Both innovations were springboards for early humans who could do more than survive; at some point we began to communicate in a nuanced way, organizing ourselves as larger groups and creating tools that would allow us to hunt more effectively, live more comfortably, and eventually become the most dominant species on Earth (for better or worse).
“It doesn’t really change our understanding of it homo sapiens, but it definitely changes the way we look at the early evolution of the human brain, ”said Amélie Beaudet, a paleoanthropologist at the University of Cambridge who was not involved in the recent study, in an email. B.eaudet noted that despite knowledge of the primitive Australopithecin brain structure possessed by the Lucy person, among other things, and the more developed crania of recent humans (dating back about half a million years ago), “we didn’t really know what happened in between. With this study, we have a better idea, even if there are still some gaps. “
More fossils always help to better understand our evolutionary arc, but instead of new finds, new technology tends to take a higher plane. The gap in our knowledge of human cognitive development is narrowing. We should be grateful for the evolution of our predecessors, because now we have the brains to figure out how it all happened.