Homo naledi: A Controversial Claim on Ancient Burial Practices
Homo naledi: A Controversial Claim on Ancient Burial Practices
New research challenges the claim that Homo naledi buried its dead, raising questions about both human evolution and emerging scientific publishing models
The Extraordinary Discovery of Homo Naledi
In the heart of South Africa’s Rising Star Cave system, paleoanthropologist Lee Berger and his team uncovered something extraordinary nearly a decade ago: the fossils of a small-brained hominin, Homo naledi. This diminutive species, with a brain about one-third the size of modern humans, was unlike any other hominin previously discovered. But it wasn’t just the fossils themselves that captured the attention of the scientific community—it was the claim1 that Homo naledi may have deliberately buried its dead around 250,000 years ago.
This assertion was groundbreaking. If true, it would imply that Homo naledi engaged in complex behaviors previously thought to be exclusive to Homo sapiens and their close relatives. The evidence pointed to intentional deposition of remains deep within the cave system, where geometric designs were also found carved into the limestone walls.
The Controversial Publication Approach
However, the way this discovery was presented to the world stirred just as much debate as the findings themselves. Instead of publishing their results in a traditional peer-reviewed journal, Berger and his team opted to release their findings through a series of unreviewed preprints on bioRxiv. These preprints were then published in eLife, an open-access journal that had recently shifted to a model where peer reviews of preprints are solicited and made public.
This unconventional approach raised eyebrows across the scientific community. Critics argued that the Berger team exploited eLife’s model to generate widespread attention before their findings had been thoroughly vetted. Andy Herries, a paleoanthropologist and geoarchaeologist at La Trobe University, remarked,
"I don’t think anything has united the paleoanthropological community like this has… This is not how you should do it.’ And we are a group of people that generally don’t agree on anything.”
The initial reviews of the eLife preprints were scathing, questioning the robustness of the evidence supporting the claim of intentional burial. The critiques highlighted significant gaps in the data and raised doubts about the interpretation of the findings.
A New Critique Emerges
A new paper published in the peer-reviewed journal PaleoAnthropology2 dealt a further blow to Berger’s claims. The study, led by anthropologist Kimberly Foecke of George Mason University, thoroughly examined the cave sediments associated with the Homo naledi fossils. Foecke and her team found no compelling evidence that the remains were deliberately buried.
The researchers utilized advanced techniques, including x-ray fluorescence (XRF) and particle size distribution (PSD) analysis, to analyze the sediments near the fossils. However, their results did not support the hypothesis of intentional burial. According to Foecke, the data,
“left out what x-ray settings were used, how the data was actually acquired.”
Her team’s attempts to reproduce the findings using standard field protocols yielded no evidence of disturbed sediments near the fossils, which would have indicated deliberate burial.
While the critique was thorough, it did not entirely dismiss the possibility that Homo naledi might have buried its dead. Instead, it argued that the evidence presented by Berger’s team was insufficient to support such a conclusion.
“It is a very good critique,” Herries acknowledged.
The Defense and Ongoing Debate
Despite the mounting criticism, members of Berger’s team defended their original findings. Tebogo Makhubela, a geochemist at the University of Johannesburg who was involved in the sedimentological research, admitted that
“the decision to use XRF and PSD was, in hindsight, incorrect.”
He noted that these methods were not well-suited to the unique sedimentary conditions of Rising Star Cave.
However, Makhubela took issue with how Foecke and her colleagues approached the critique. He argued that their work should be seen as a preprint—an ongoing piece of research—rather than a finalized published paper.
“Our team published a preprint, open for comments from colleagues and the public,”
Makhubela stated. He insisted that Foecke’s critique treated their preprint as if it were a definitive, published paper, which he deemed unfair.
In the eLife model of “reviewed preprints,” authors are encouraged to revise their work in response to public and peer feedback. However, the Berger team has yet to make any substantial revisions to their preprint. Instead, they are preparing a revision that will include new data on trace elements within the sediments, which they believe will bolster their original claim of intentional burial.
The Broader Implications
This debate over Homo naledi’s burial practices has broader implications for both our understanding of human evolution and the future of scientific publishing. If Homo naledi indeed buried its dead, it would suggest that this species possessed cognitive and cultural capacities far beyond what was previously imagined for hominins with such small brains.
On the other hand, the controversy surrounding the publication of these findings highlights the challenges and potential pitfalls of emerging models in scientific publishing. While the eLife approach of publicly reviewed preprints aims to foster transparency and open dialogue, it can also lead to confusion and the premature dissemination of unverified findings.
Critics like Mike Morley, a geoarchaeologist at Flinders University, argue that the Berger team’s use of eLife’s process blurred the lines between peer-reviewed science and preliminary research. Morley said,
“eLife’s model may have issues, but what’s happened with Lee and his team is that they very quickly realized that, and they’ve exploited those issues to their own benefit.”
The Future of Homo Naledi Research
As the scientific community awaits the revised preprint from Berger’s team, the debate over Homo naledi’s burial practices is far from over. Some, like Robyn Pickering, a geochemist at the University of Cape Town, believe that the team should retract their preprints and start anew with more rigorous methods and reporting standards. Others, like eLife Co-Editor-in-Chief Timothy Behrens, see the ongoing revisions as a sign of science working as it should, with open scrutiny and dialogue.
Ultimately, this controversy serves as a reminder of the complexities of studying ancient hominins and the importance of careful, methodical research in unraveling the mysteries of human evolution. As Herries noted,
“It’s very difficult to walk ideas back once they’re out there,”
…emphasizing the lasting impact that such high-profile claims can have on both public perceptions and scientific discourse.
The story of Homo naledi is still being written, and with it, the narrative of our own understanding of what it means to be human. Whether or not this small-brained hominin buried its dead, the ongoing research into its life and behavior will continue to shape our understanding of human evolution for years to come.
Berger, L. R., Makhubela, T., Molopyane, K., Krüger, A., Randolph-Quinney, P., Elliott, M., Peixotto, B., Fuentes, A., Tafforeau, P., Beyrand, V., Dollman, K., Jinnah, Z., Brewer Gillham, A., Broad, K., Brophy, J., Chinamatira, G., Dirks, P. H. M., Feuerriegel, E., Gurtov, A., … Hawks, J. (2023). Evidence for deliberate burial of the dead by Homo naledi. https://doi.org/10.7554/elife.89106.1
Foecke, K. K. (n.d.). No sedimentological evidence for deliberate burial by homo naledi – A case study highlighting the need for best practices in geochemical studies within archaeology and paleoanthropology. PaleoAnthropology. https://doi.org/10.48738/202x.issx.xxx