So we’re both just as bright, but who’s better-looking? Pascal Goetgheluck/Science Photo Library

Great minds grow alike. Evidence from Neanderthals’ skulls suggests that their large brains grew in the same way as ours do. That in turn suggests that Neanderthals were perhaps not so cognitively different from us – although not everyone agrees with this interpretation.

We know that Neanderthal brains were roughly the same size as ours, making them the largest among all known extinct human species. To get a sense for how they grew over an individual’s life, Christoph Zollikofer at the University of Zurich, Switzerland, and his colleagues looked at 15 Neanderthal skulls. Six belonged to adults and nine to children; the youngest was an individual who died just weeks after birth, the oldest a child who died aged roughly 12.

Using software, they generated 3D casts of the brain case – effectively allowing them to study changes in the rough shape of the Neanderthal brain through childhood. They then compared the findings with patterns of brain development in modern children.


The team found evidence that at birth, Neanderthal brains were subtly but significantly longer, wider and flatter than modern human brains. Subsequently, though, the Neanderthal brain developed rather like ours: certain regions, including the cerebellum, expanded quickly during childhood and then became some of the slowest-growing areas in early adulthood.

It’s difficult – perhaps impossible – to work out exactly how such changes in the brain relate to particular cognitive traits. But if Neanderthals and us share this pattern of brain development, it becomes just that little bit harder to argue that Neanderthals were cognitively different from us, says Zollikofer.

This conclusion fits with archaeological evidence that Neanderthals were just as capable of sophisticated behaviour as modern humans. Both species used similar symbolism and independently made similar advances in technology, for instance, and Neanderthals may have shared our skill with language.

Hybrid lifestyle

Zollikofer thinks his study might help us better understand what life was like for the rare individuals in prehistory who were hybrids. Their Neanderthal DNA survives in many people alive today.

“These hybrids must have been well integrated [into human society],” he says. Integration may not have been too much of a challenge because their mixed genetic heritage might not have had an adverse effect on brain development, meaning hybrids might have behaved no differently from anyone else, the team suggest.

Philipp Gunz at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, is less convinced that the work closes a cognitive gap between Neanderthals and modern humans. In fact, he and his colleagues analysed the shapes of nine Neanderthal skulls in 2010 – including several specimens also used in the new study – and arrived at the opposite conclusion: namely, that Neanderthal and modern human brains looked similar at birth and then developed differently.

There are a few reasons why a similar analysis of the same skulls could have delivered such different results, says Gunz. One is that there is a degree of guesswork in reconstructing the shape of Neanderthal brains – particularly for children. “The bones of a baby’s skull are thin and easily distorted,” he says. “And the cranial sutures are not fully fused.”

In other words, there are gaps between the bony plates of a baby’s skull – and that means there’s wiggle room when it comes to reconstructing the 3D shape of the skull and the brain it once contained. “We have to be honest about limitations of these methods,” says Gunz.

Emiliano Bruner at the National Research Centre on Human Evolution in Burgos, Spain, is also sceptical.

“A surface analysis of some braincases can say nothing about cognition or cognitive differences,” he says. “I think [researchers] should not put cognition on the table every time they find a morphological difference between specimens.”

Journal reference: Current Biology, DOI: 10.1016/j.cub.2016.06.022

!--more-->

Read more: Our first sex with Neanderthals happened 100,000 years ago