Controversial claims about extinct humans are stirring up evolution research Premium

Some scientists have argued the small-brained H. naledi buried their dead in Rising Star Cave in South Africa more than 240,000 years ago, and may also have decorated the cave walls with engravings. But not all are convinced

In June, researchers led by palaeoanthropologist Lee Berger published sensational claims about an extinct human species called Homo naledi online and in the Netflix documentary Unknown: Cave of Bones. They argued the small-brained H. naledi buried their dead in Rising Star Cave in South Africa more than 240,000 years ago, and may also have decorated the cave walls with engravings.

If true, this would be an astonishing new entry in the annals of human evolution. But many scientists – including ourselves (the authors of this article, along with Ian Moffat at Flinders University in Australia, Andrea Zerboni at the University of Milan in Italy, and Kira Westaway at Macquarie University in Australia) – are not convinced by the evidence in the three online articles.

The peer reviewers of these articles and the journal editor found that the evidence was “inadequate” and suggested a comprehensive list of changes that would be needed to make the articles’ argument convincing. More recently, a strongly worded, peer-reviewed critique by one of us (Herries) concluded there was not enough evidence to support the hypothesis that H. naledi carried out intentional burials.

What would “enough evidence” for such claims look like? As we argue in a new comment piece in Nature Ecology and Evolution, there are modern scientific techniques that could provide it.

There are many kinds of evidence for human evolution, such as fossils and artefacts, and the sediment (or dirt) from which they are recovered. There are also many new and creative ways we can use to study this evidence.

We argue that the routine use of these techniques to generate supporting data will help avoid future controversies and increase public confidence in such claims.

Human evolution researchers deal with very long timescales, often measured in hundreds of thousands – or even millions – of years. Because of this, we often work with geologists and other Earth scientists, and use their ideas and tools to analyse traces of ancient humans.