In today's upside-down, nonsense world, the models are more important to SCIENCE! than science is, however, and changes to the models, even if you have data that makes it imperative is very, very hard. You just don't get any headway making inroads against established and entrenched paradigms on which scientists have built their whole careers. This is especially true if political or business interests have a vested interest in only promoting results that suit their agenda, and they pay the bills for science to actually happen. This is the scenario we are in today, where there is little incentive to be the iconoclast with some intriguing new data that you're trying to make sense of, rather than the person who sweeps that intriguing data under the rug and finds some way to prop up the current year narrative instead.
That said, sometimes those iconoclasts do exist in spite of the incentives to keep them quiet, and sometimes they do present intriguing data and is interpreted in a framework that is different than the prevailing narrative. And sometimes we should pay attention to those new models, because they have something interesting to say—even if they turn out to be wrong, they invariably teach us something significant about whatever model we do end up with, even if it's a modified version of the status quo.
A few models that I've recently been made aware of might fall into this category. They might represent real challenges to the status quo; or at least in a fair world where they're given a fair hearing, they might. I find them intriguing and worth further investigation.
The first is called Out-of-America. This is in contrast to Out-of-Africa that proponents of the evolutionary progression and migration of modern humanity has propagated as the only serious model that we can be looking at. It comes in several varieties, each with various intriguing solutions to problems, but each with problems of their own.
- Out-of-America I: Human origins among New World primates rather than Old World great apes. This is the most drastic, but given the paucity of fossil evidence to support any model currently under consideration, it's actually not as far-fetched as it should sound at first blush—if you keep in mind, again, that the model currently in use is not based on rock-solid mountains of data, but rather on one plausible interpretation of pretty scanty data. Cebidae (capuchins and squirrel monkeys) actually have a number of shared features with humans and advanced apes, and have even more behavioral features with humans than great apes.
- Out-of-America II: Human origins from an east Eurasian hominid who crossed Berengia to the New World, speciated into modern humans, and then migrated back to the Old World, replacing (with some admixture while passing through Denisovan or Neanderthal lands) Old World hominids. This model actually fits genetic data fairly well (the data set that is throwing off all kinds of past paleo/archaeological models). Another advantage is that geographic isolation is what is seen as correlated with speciation, and this is the only model that provides it. This actually interprets Y-DNA evidence for diversity in Africa as extended and more substantial admixture with various local hominids rather than of in situ development. This model of colonization and migration leading to greater genetic diversity as various population groups converge on one area and blend will be important later when we talk about another PIE model too. There are other interesting data points in the fossil record that suggest that the peopling of Africa from Eurasia (rather than the other way around) long ago has some merit.
- Out-of-America III: Similar to OOAII except only taking place at the end of the last Ice Age, especially with regards to the "Asiatic" physical features, which are actually "native" to the Americas in this model. There is actually some pretty good archaeological evidence to support this model, which is only ignored because nobody knows how to interpret it under our current model of Clovis coming from Siberia. That said, while it completely turns over the Clovis First model, it is still much more conservative than the prior two models, but also could work with them.
- Out-of-America IV: This is basically II and III together. Back-migration from America during the Late Pleistocene and then again during the Early Holocene. Early modern humans become a North American innovation that spread across the Old World from Berengia, replacing (and mixing to some small degree) with archaic humans like Denisovans, Neanderthals, or Homo heidelbergensis. Later, East Asian and circum-Arctic populations migrated again from the New World to the Old.
It's important to note that the Out-of-Africa model has evolved somewhat too from what it was a few years ago (where it was basically modern humans from Africa completely replaced all other archaic humans globally.) The current Out of Africa model does have back-migration from Eurasia, and it has to because genetic studies indicate that archaic human admixture was present in Africa as well. A newer model already is close to Out of America in many ways; to account for the majority of y-chromosome lineages found in Africa, as well as sites in South Africa with skulls that cluster with Eurasian skulls, etc. has modern humans developing not in Africa or America exactly, but in Arabia or even as far as India before back-migrating into Africa. This also explains the persistence of archaic human fossils almost to the very eve of the Holocene; because they were being replaced by immigrants from outside Africa rather than global archaic humans being replaced by immigrants from Africa. It also explains why over-hunting and the extinction of the megafauna is a plausible model in the Americas and Europe, for example, but not Africa—because modern humans were relatively late arrivals. This theory ends up being nothing more than a more conservative version of Out-of-America IV. The staggering linguistic diversity of the Americas is, on the other hand, cited as evidence for the antiquity of modern humans in North America in spite of their lack of genetic diversity (relatively speaking). In fact, genetic diversity is reinterpreted here; it doesn't mean that it's the place where a group originated and then sat around diversifying; it means the place where the subject population immigrated to and found diverse populations to mingle with. On the balance, that's a more sensible approach, in my opinion, anyway.
That last is what I referred to up above as well; if we're completely misinterpreting in many cases the cause of diversity; it's not the result of long-time residence, but rather the result of the mixing of long-time residents with another group that replaced them (but not completely 100%, resulting in some mixed DNA in the ensuing population) can the same logic be applied linguistically? Johanna Nichols has proposed a variation on the prevailing Kurgan Theory of proto-Indo-European Urheimat that has it originating further east than we thought, and presenting diversity (especially in the Balkans) because two large streams—a northern and southern dialect group—came together again there after being separated during a gradual migration westward. This basically has pre-Indo-European as a relative of Uralic languages in the Bactrian area that gradually migrated westward, shedding language families as it went (starting with Tocharian), superimposing themselves over a population of early Caucasian or Kartvelian speaking hunters and early agriculturists who lived in the Pontic-Caspian grasslands. This substrate is what led to a more "modern" late PIE, which continued to diversify into the languages that we later see in Europe and elsewhere.
This is quite a sophisticated model, but I have to highlight that after 10 years, it's still seen as kind of a fringe model. Again; is this because of entrenched academic opinion resisting models that will throw out their beloved work of decades, or because the model really does need more work to seriously threaten it? I don't know enough specialist knowledge to make that judgement.
But even the classic Kurgan model proposes that the prestige dialect that led to real, honest-to-goodness PIE came from the northeastern corner where horse domestication and "royal" grave goods starts first, and they later dominated the rest of the region (although it posits that the region already spoke closely related languages or dialects to PIE even so.)
Here's some new maps that show this spread with an emphasis on how PIE broke up in its early years and turned into the stocks that later emerged as Indo-European families. These maps include the Maikop culture, and even propose that the Anatolian languages came from them; which seems unlikely. Otherwise... well, they're quite pretty.
|Samara culture c. 5,000 BC|
|Early Yamna culture c. 3,500 BC|
|Late Yamna culture c. 2,000 BC|
|Early Indo-European migrations c. 1,500-1,000 BC|
|Early historical placement of I-E languages c. 1,000-500 BC|
|Indo-European distribution during historical antiquity c. 500 AD|
|Medieval distribution of I-E languages c. 1,000 AD|