Brain of Homo Naledi Estimated
The intriguing hominid fossils from a South African cave make news again. This time, the discoverer and a team of anthropologists learn more about the brains of these creatures. Were they people?
In 2013, the world was shocked to hear of bones of Homo deep within the Rising Star Cave system in South Africa. Bones were found in a chamber very difficult to reach. Cavers helped to retrieve the fossils for Lee Berger, whose team named the creatures Homo naledi after the name of the Dinaledi Chamber where they were found. Many questions emerged from the discovery: were they human? Did the individuals crawl into this chamber, or were they buried or tossed into it? Did animals drag the carcasses into the cave? Now, additional measurements of the skulls of individuals have been published in PNAS by Ralph Holloway, Lee Berger, John Hawks and other paleoanthropologists. You can get a gist of what they concluded from a long headline at Science Daily: “Where hominid brains are concerned, size doesn’t matter: The human-like features of Homo naledi’s brain surprise research team that examined fossil’s brain imprints.” The PNAS paper begins with a statement of the significance of their latest findings:
The new species Homo naledi was discovered in 2013 in a remote cave chamber of the Rising Star cave system, South Africa. This species survived until between 226,000 and 335,000 y ago, placing it in continental Africa at the same time as the early ancestors of modern humans were arising. Yet, H. naledi was strikingly primitive in many aspects of its anatomy, including the small size of its brain. Here, we have provided a description of endocast anatomy of this primitive species. Despite its small brain size, H. naledi shared some aspects of human brain organization, suggesting that innovations in brain structure were ancestral within the genus Homo.
This announcement is sure to arouse fervent discussion among evolutionists and creationists (who will dispute the dates and the evolutionary statements). Most importantly, the brain endocast shown in the paper looks very human. Berger and co-authors try to make the case that “The cranial, dental, and postcranial remains of H. naledi exhibit a mosaic of derived, humanlike traits combined with primitive traits shared with Australopithecus and other stem hominins,” and yet they classify it as Homo, “man,” not –pithecus, “ape.” The endocasts produced for this paper, though small, show such remarkable similarity to human brains, and such differences from Australopithecus, that the team was surprised. “The research highlights the humanlike shape of naledi’s tiny brain, surprising scientists who studied the fossils.”
In the press release from the University of Witwatersrand, reproduced by Science Daily, John Hawks sees a disconnect between theory and fossil evidence:
The small brains of Homo nalediraise new questions about the evolution of human brain size. Big brains were costly to human ancestors, and some species may have paid the costs with richer diets, hunting and gathering, and longer childhoods. But that scenario doesn’t seem to work well for Homo naledi, which had hands well-suited for toolmaking, long legs, humanlike feet, and teeth suggesting a high-quality diet. According to study coauthor John Hawks, “Naledi’s brain seems like one you might predict for Homo habilis, two million years ago. But habilis didn’t have such a tiny brain — naledi did.”
Some of the team members are almost ready to conclude that these creatures had human-like behaviors, and even language. “It’s too soon to speculate about language or communication in Homo naledi,” said coauthor Shawn Hurst, “but today human language relies upon this brain region.”
Another example of small people with small but modern-shaped brains were the hobbits, Homo floresiensis. Paleoanthropologists were wrong about diet and brain size. Are they now wrong about human variability?
A humanlike brain organisation might mean that naledi shared some behaviours with humans despite having a much smaller brain size. Lee Berger, a co-author on the paper, suggests that the recognition of naledi’s small but complex brain will also have a significant impact on the study of African archaeology. “Archaeologists have been too quick to assume that complex stone tool industries were made by modern humans. With naledi being found in southern Africa, at the same time and place that the Middle Stone Age industry emerged, maybe we’ve had the story wrong the whole time.“
But a different conclusion can be drawn. Instead of imagining that “primitive” ancestors of humans “evolved” toolmaking abilities and complex brains, one could conclude that these were fully human with some differences in size and anatomy. So many speculations about human evolution have been overturned over the decades, one might well call paleoanthropology the Science of Being Perpetually Wrong.
In their 2017 book Contested Bones, Sanford and Rupe concluded that the weight of evidence shows Homo naledi to fit within human variability, as does Homo erectus. Their comparisons of hands, feet and other parts of post-cranial (below the head) anatomy show very close resemblance to human bones. The small brain size should not be surprising, as there is a great deal of variability today in those unquestionably human. Consider skull sizes between the smallest midget and the largest giant. Big skulls and brains do not necessarily correlate with intelligence, as early Darwinists thought. It’s quality, not quantity.