Everything Neandertal is not bad14 Oct 2016
This is not a bad story about Neandertals by Melissa Hogenboom: “What Neanderthals’ healthy teeth tell us about their minds”. It’s an overview of what scientists learn from various kinds of dental studies.
But I wanted to comment on one thing:
"We realised nobody had directly compared Neanderthal [teeth loss] to modern humans, so we didn't realise Neanderthals had [slightly less] tooth loss," says Weaver.
This flies in the face of previous studies, which suggested that several Neanderthals lived long after losing all, or nearly all, their teeth.
But bizarrely, the finding that Neanderthals apparently had healthy teeth actually suggests something rather negative about them.
I don’t disagree that there is a slight difference in tooth loss. That does not contradict the real observation that some Neandertal individuals had extensive premortem tooth loss.
I agree that some people have made more cultural conclusions from the observation of tooth loss than the data warrant. I wrote about this back in 2005, when the subject of discussion was total premortem tooth loss in the Dmanisi skull D3444: “Caring for the edentulous”. My conclusions today don’t differ from then:
In the case of life history variation, I think that the survival of a small number of individuals under extraordinary circumstances says little about the habitual capabilities of a species.
A handful of Neandertals lived with fairly extensive loss of dental function, but that probably doesn’t tell us much about Neandertals that we do not already know about many primates.
What I really object to in the linked article is the way this topic is framed: This good thing about Neandertals “bizarrely suggests something negative about them.”
Often in human evolution, research is presented with a simple storyline that goes like this: “This bad thing everybody knows about, well, guess what—it’s actually good when you think about it from the evolutionary perspective.”
That’s the storyline of the sickle cell mutation. It causes disease, but it is an adaptation to malaria. It’s also the storyline of the “thrifty genotype” idea: Diabetes is bad, but its occurrence today may be a side effect of ancient adaptations to food scarcity.
That framing doesn’t erase the bad aspects of such biological traits, but it does give people a different way of thinking about why bad things happen. “Everything bad is actually good” is a fairly useful frame for teaching human evolution.
The opposite storyline is also pretty common. “That good thing that everybody knows about? Well, guess what—it’s actually bad when you think about it from the evolutionary perspective.”
This is how the invention of agriculture gets portrayed nowadays. Jared Diamond famously called it, “The worst mistake in the history of the human race.” The idea is that once upon a time, humans were adapted to a hunter-gatherer existence, and agricultural subsistence caused scores of bad unforeseen effects.
This “everything good is actually bad” storyline is especially common when it comes to studying Neandertals. For example, Neandertals seem to have eaten lots of meat. Does that mean they were successful hunters optimizing resources in a harsh environment? No, it means they failed to build knowledge of plant foods, putting them at extreme risk of extinction when times got tough.
Another example: Some Neandertal sites seem to have different assemblages of tools that may be suited to different functional tasks, for example some toolkits include many scrapers for preparing hides, while others lack such a dominance of scrapers. Is this evidence of clever and flexible Neandertals? No, to some archaeologists it was evidence that Neandertals must have behaved like herd animals, with women and children in some camps, and small groups of bachelor males in others.
My favorite essay on such stereotypes is by the archaeologist John Speth: “News Flash: Negative Evidence Convicts Neanderthals of Gross Mental Incompetence”. He humorously reviews a series of extravagant claims about what Neandertals couldn’t do, mostly tests that would fail when applied to some groups of modern humans.
Every so often, new evidence convincingly debunks one of these Neandertal stereotypes. For example, over the past ten years, a series of papers describing starches and phytoliths in Neandertal dental calculus have documented their use of plant resources, including cooking of some grains and the possible use of medicinal plants. In this case and many others, the press has reported the “surprising” conclusion that Neandertals were very much like modern human subsistence foragers.
Just once, I would like to see a journalist report such results as unsurprising evidence that past archaeologists were incompetent.
Now I don’t want to go overboard in the opposite direction. There probably really were some strange things about some Neandertals. Culture did evolve, and the evolutionary history of Neandertals probably yielded cultural abilities that humans lack, just as modern humans may have abilities that they lacked. In other words, I do not assume that they were merely modern humans with browridges.
But these are among the hardest ideas to test with archaeological evidence. At the same time, ideas about Neandertal cognitive difference align with persistent stereotypes about Neandertals. For that reason, I maintain an attitude of skepticism.
We know a good amount. Some of the cultural behaviors of recent and living modern humans have never been noted in Neandertal sites. But their tools, the traces of animals and plants that they ate, and their use of space show that Neandertal subsistence behavior had a lot in common with modern human subsistence foragers.
Many modern human subsistence foraging groups have left little or no evidence of “symbolic” artifacts, “complex site structure”, musical instruments, projectile weapons or similar trappings. We now know that Neandertals used pigments, engraved objects and rock surfaces, wore ornaments, made and used many kinds of bone tools, used shellfish, birds and small mammals—basically all things that past stereotypes held they didn’t do.
The point is, the difference between Neandertal and modern human behavior is clearly not a yawning chasm. They overlapped.
Studying Neandertal biological traits in combination with archaeology has a lot to offer to understanding their behavior. Dental pathology is a great avenue to understand how their health relates to their subsistence behavior. For example, Neandertals were once believed to have a much higher incidence of developmental dental pathologies than modern humans, traits like linear enamel hypoplasias that result from stress on the developing teeth from nutritional shortfalls or disease. It turns out that many modern human groups have just as high an incidence of such dental traits as Neandertals, including children from many agricultural groups.
Both Neandertals and prehistoric modern human subsistence foragers have vastly lower incidence of dental pathologies like caries when compared to most agricultural peoples, so it’s interesting to see that tooth loss was actually less among Neandertals than in the prehistoric modern human groups.
Better teeth may reflect the basic fact that Neandertals died faster than the Upper Paleolithic modern humans that followed them. By our best estimates (provided by Rachel Caspari and Sang-Hee Lee), Neandertal mortality was greater across the adult life span. Most known Neandertal dental remains come from relatively young adults, less than thirty or so years old.
Such high mortality probably does indicate something about Neandertal social relationships. Today’s human cultures owe much to the knowledge and experience of older adults, common in human societies. If those older adults were rarer, with some groups lacking older adults altogether, Neandertal cultures must have been poorer for it.
But adults in their twenties and thirties are not poor caregivers today. In fact, they are the primary caregivers toward both children and the most aged adults in our societies.
For that reason, I resist the framing that Neandertals good teeth may have meant they took less care of the sick. It may well have been true that sick Neandertals did not live as long, or have as good a chance of recovery. But I attribute that to the basic challenges of subsistence, not social incompetence.
Caspari, R., & Lee, S. H. (2004). Older age becomes common late in human evolution. Proceedings of the National Academy of Sciences of the United States of America, 101(30), 10895-10900. doi:10.1073/pnas.0402857101
Speth, J. (2004). News flash: negative evidence convicts Neanderthals of gross mental incompetence. World archaeology, 36(4), 519-526. doi:10.1080/0043824042000303692