FOXP2 is one of the most famous genes out there; notable for containing two mutations linked to language in humans. These mutations are also in Neanderthals, which is strong evidence they could speak like us 1.
However, it turns the importance of FOXP2 may have been overblown, despite the fact we've been studying it for more than 20 years. A recent study looking at the gene in more than a thousand people failed to find the purported link to language evolution 2.
As well as changing our understanding of language evolution, this also has implications for speech in ancient human species. Can we still be confident Neanderthals could talk like us? What other evidence is there?
FOXP2 failure
The FOXP2 gene was one of the first to be linked to language, way back in the early 2000s. People with mutations that broke this gene had problems with language, cementing a link between the two.
The mere existence of a link is interesting, but not the most important thing about our version of FOXP2. It turns out that our version of the gene had been evolving relatively recently. Specifically, positive selection appears to have spread the human mutations throughout our species ~200,000 years ago. This spread suggests that (a) these mutations were really helpful for our survival and (b) gave us a unique ability. Does that sound like language to anyone else 1?
Around a decade later we found that Neanderthals and Denisovans had the same mutations in FOXP2. Surely this meant they also had language!
However, some researchers became skeptical. How could FOXP2 be present in Neanderthals, who split from us more than half a million years ago, and us if it only evolved recently? Clearly, something was amiss.
So now, nearly 20 years after it was first discovered, researchers have returned to FOXP2. This time, they looked at the gene in the hundreds of human genomes we've sequenced in the intervening years. This huge sample revealed that the evidence of positive selection for FOXP2 just wasn't there.
So it's back to the genetic drawing board for explaining language.
Neanderthal noises
It's taken decades, but Neanderthals are slowly recovering from their Victorian-era reputation as savage brutes. Does this discovery undo any of this?
Fortunately for the Neanderthals' PR team, there are still plenty of other indicators they had language like us.
For instance, the shape of your ear bones influences what sounds you can hear. Unlike other primates, our bones are great at hearing noises at 1-6 kHz, which just so happens to be the range speech falls in. Neanderthals also fall in this range, meaning they could hear speech-like noises 3.
They could also probably make these noises too. The hyoid bone in your neck is the source of many mouth muscles we use in speech. Thus, its shape has a big influence on the noises we make. And, you guessed it, Neanderthals had a hyoid a lot like ours.
As well as helping them make some noises, this bone also indicates they had lost other noise making capability as well. Some species have air sacs around their hyoid that help them make loud noises. Humans (and Neanderthals) have lost this ability, in exchange for being able to make clearer sounds3.
Of course, language is more than just hearing and making certain noises. Otherwise, there'd be more than one band fronted by a parrot. So is there any indication Neanderthals were actually using their noises for language?
What about language?
Clearer evidence of language is harder to come by, given Neanderthals never had the decency to write anything down. Nevertheless, there are some who say that their culture is so complex that they must have had some language capacity. Particularly to pass it on from generation to generation. It certainly is quite hard to teach someone by just going "ooga ooga"2.
Notably, many aspects of Neanderthal technology were on par with contemporary Homo sapiens. We both made similar tools that required extensive forethought and planning, including specialised inventions for specific roles. We also both created a variety of artistic artefacts, ranging from jewellery to cave art2.
So if we want to argue that our species had language back then, it follows we must also conclude Neanderthals were a chatty bunch too.
So, even without FOXP2 there's good reason to think Neanderthals were talkative. Which means I've just waffled on for a thousand words to essentially say "nothings changed to see here".
Hopefully, you still found it interesting.
References
- Dediu, D. and Levinson, S.C., 2018. Neanderthal language revisited: not only us. Current Opinion in Behavioral Sciences, 21, pp.49-55. https://doi.org/10.1016/j.cobeha.2018.01.001
- Atkinson, E.G., Audesse, A.J., Palacios, J.A., Bobo, D.M., Webb, A.E., Ramachandran, S. and Henn, B.M., 2018. No Evidence for Recent Selection at FOXP2 among Diverse Human Populations. Cell. https://doi.org/10.1016/j.cell.2018.06.048
- Dediu, D. and Levinson, S.C., 2013. On the antiquity of language: the reinterpretation of Neandertal linguistic capacities and its consequences. Frontiers in psychology, 4, p.397.
