It’s almost another day here. So this is a graphical image of why I see a divide between Homo and other hominins. a and c are human, e is Homo erectus. b and d are chimp and f is Austalopithecus (Lucy) Homo erectus emerges in Africa with precious few potential intermediates, but with a very different skeleton. He rapidly dispersed throughout Europe and Asia, with even some evidence that he sailed (!) to distant islands. Did he have a theory of mind? If he built boats and sailed them I would imagine that took cooperation, which I would propose requires a theory of mind. The figure by the way is a copy of one from Bramble and Lieberman.
Yep, here too.
How does habilis fit into your thinking? Or nadeli? Or sediba?
For habilis it’s tricky because not everyone agrees where they group. I would place them as closer to Australopithecines than Homo. As to naledi, they are an oddball species, ape-like in their rib cages and arms, probably an offshoot of a non-Homo hominin. I know people argue they had intelligence because of how they were buried (buried themselves?). I think we need more data. Lee Berger, who found naledi, is something of a sensationalist and controversial among paleoanthropologists. He is also responsible for claiming sediba as ancestral. Lots of disagreement there.
The record is really sparse between 3 and 2 mya. And hotly contested. There is no clear tree of ancestry leading to Homo. If anything it’s a thicket with a gap.
Gaps can be filled, I acknowledge. But it’s a pretty big gap from Lucy to Homo erectus.
Signing off.
I would like to see your reasons why for assigning Habilis closer to the Australopithecines than Homo. Naledi is very human like in the hands, feet and ankles. Long legs. I think naledi fits in the adaptive grade of Homo quite well. Also, I think its very premature to seriously discuss moving habilis out of homo. People like Wood who push this idea focus way too much on brain and body size. We need more post cranial remains before I think we can really consider something like that. Also, I think you have Lee wrong. Every time I’ve had the pleasure of meeting and speaking with him he came off very tentative. Especially with naledi (im aware of the various news reports and comments by those like Tim White).
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Thanks for sharing your thoughts, Ann. Goodnight!
@Christy
It’s late and it would take too long to go through each section. They begin by describing what it is about language and language acquisition we must explain. Then at every turn they say something like this:
The question of interest is whether these seemingly modest claims about animal signals help us understand the evolution of our capacity to represent words, including not only their referentiality but their abstractness, their composition via phonology and morphology, and their syntactic roles. Our simple answer is No, for five specific reasons: for animals, (i) acquisition of the entire lexicon is complete by the end of the early juvenile period, and for most species, the sounds or gestures are innately specified; (ii) those sounds and gestures refer, at best, to directly observable objects or events, with great uncertainty about the precise meaning, and no evidence for signals that map to abstract concepts that are detached from sensory experiences; (iii) with a few rare exceptions, individuals only produce single utterances or gestures, never combining signals to create new meaning based on new structures; (iv) utterances are holistic, with no evidence of complex syntactic composition derived from an inventory of discrete morphological elements; (v) the utterances or gestures are not marked by anything remotely resembling grammatical classes, agreement, etc. Given these differences, it is not possible to empirically support a continuity thesis whereby a nonhuman animal form served as a precursor to the modern human form.
They go through the fossil record, concluding that language developed after Neanderthals. I have seen other opinions, at least concerning the intellectual abilities of Neanderthals. Bottom line fossils can’t tell us about the evolution of language.
Molecular biology and neurobiology: We don’t know nearly enough.
Modelling: not grounded in experiment or the internal and external processes that are necessary for language to work.
They close with this:
Should such discoveries from comparative animal behavior, paleontology, neurobiology, and archaeology be made, along with greater depth of understanding of gene-phenotype mapping, it would open the door to more relevant genomics and modeling. These are all big IFs about the nature and possibility of future evidence. Until such evidence is brought forward, understanding of language evolution will remain one of the great mysteries of our species.
They don’t see any evidence. They believe that’s what happened but can’t find evidence of it.
Going to bed now, she said, while herding the dogs to the kennel and then turning out the light.
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I defintely agree with you that the record is sparse between 3 and 2mya. But I would like your thoughts on LD-350-1
But it is rarely explosive growth, as required here. Rabbits, sure, but not hominins.
I don’t think the gap is a big as you think it is. Let’s say LD 350-1 is Homo, which I think it is. That’s Homo at 2.8mya. Not too long after afarensis. There is also some debate over sediba. Australopithecine or Homo? What if it’s Homo? Well there’s another Homo at 2 mya. So yes, more data would be fantastic but it’s not a big of a gap potentially as some make it out to be. Habilis we need to withhold judgement right now. I think there is too much variation is Habilis to be one species so I take the position that it should be divided into two. H. habilis and H. rudolfensis. We just need more post cranial elements to make that decision. For instance if we found a limb bone of H. rudolfensis and it was like those of H. ergaster that would support keeping them in Homo
Why does it have to be explosive?
There are better and worse models for language evolution, it’s not guesswork and imagination. I’m just letting you know that you are speaking outside your area of expertise and what you are saying sounds ignorant. We aren’t talking about a “rationale,” we are talking about what we know about human language. We know a lot about child language acquisition, diachronic language change, and the cognitive psychology of language use. This knowledge is evidence based and allows us to create models of how languages develop, change, and are transmitted in communities. Throwing out a “we weren’t there, so we can’t know for sure” to license any old fantastical guess is as silly in this situation as it is in flood geology.
What I know about biological evolutionary processes is irrelevant here, (and if it were just about evolution, I would be much less confident I know what I’m talking about) we are talking about linguistic evolution. How much have you actually looked into the specific topic of the evolution of language? Nothing you have said makes me think you have studied it.
Somehow equating the evolution of the human mind with language sounds completely unwarranted to me, because language is inherently a socially transmitted construct, not an intellectual capability. Every individual who speaks a language was taught the language socially, it’s not like geometry. No one just “figures it out” because they are smarter than the next guy.
But it’s not my “personal instinct,” Josh. It’s basic facts I know about the field I work in and have two master’s degrees in. I was doing you a favor by letting you know what you are proposing is laughable to people in my field. If you honestly just want to tell linguists that they need to ignore the consensus of their field and open their minds to imaginative scenarios with no basis in observed reality, well that sounds familiar, but it’s not usually the kind of argument I’d expect from a scientist. 
Claiming the origins of human language are still a mystery is not the same thing as saying they see no evidence for the gradual emergence of human language. I only read the abstract, but where in this paper does anyone claim anything close to “language probably emerged with a discontinuous group”?
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I know of no natural disaster that would be widespread enough to reduce a large population and yet leave ideal conditions for subsequent rapid growth. What do you have in mind?
We have lots of examples of geographic and cultural isolation. None of them involve complete genetic isolation except when there is complete geographic isolation, which is not in view here.
I find that extremely implausible. Based on all historical evidence, humans will attempt to mate with just about anything that looks remotely human. They also have quite a strong aversion to incest (as do apes in general), which further discourages mating within a single family. This looks like an ad hoc hypothesis with no scientific motivation.
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You consistently confuse “human” as used in scientific literature and “human” as used in everyday discourse. Word meanings are determined by usage, not by fiat. In everyday usage, “human” is exactly equal to H. sapiens, which is not confusing at all to the average person since we are the only living example of the genus Homo. In scientific discourse, where many extinct examples of Homo must be taken into consideration, “human” takes on a different meaning. Constantly insisting that everyone use “human” in its scientific sense is a waste of time and energy, as well as a hindrance to actual communication.
Chimps have theory of mind on the order of human children below the age of 5. (Yes, I used human in its colloquial sense.) This is presupposed by the fact that chimps practice deception. I can supply a citation, if you like.
Language requires a population of speakers. It is as unlikely for two people to invent a language as it is for a single breeding pair to give rise to a species. The rest of your post is a long list of “maybe this, maybe that, maybe maybe maybe.”
I don’t have time to read the paper right now, but I suspect the distinction is between full-blown “modern” language – with fully modern grammar – versus a “proto-language.” Proto-language can be of varying complexity, beginning from gestures and simple one-word communications, which do not require symbolicity. Proto-language most likely began with erectus, and Neanderthal certainly possessed an advanced form of it, although not fully modern language. Hope that helps.
It was a spiral process.
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Because you’ve been looking for two-person bottlenecks that could escape detection – that won’t be detected by PSMC, that don’t reduce heterozygosity too much. A prolonged small population would not escape detection.
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I find a whole lot of this going on. Check out the definition of an ad hoc auxiliary hypothesis in Cladistics and the Origin of Birds, p. 27 (emphasis mine):
An ad-hoc auxiliary hypothesis is one that has been formulated for the specific purpose of restoring agreement between a hypothesis and falsifying observations; it serves no independent explanatory function and does not entail any significant, independently testable implications (e.g., Hempel 1966, Popper 2002). Although ad-hoc auxiliary hypotheses are often used to protect favored hypotheses (Kuhn 1970), and although they may be empirically valid, they actually interfere with testability (Hempel 1966, Popper 2002) by increasing the range of observations with which a hypothesis is compatible. If the introduction of ad-hoc auxiliary hypotheses were considered legitimate, they could be used to explain away all falsifying observations, rendering a favored hypothesis immune to any criticism. Repeatedly obtained observations that contradict a hypothesis should be accepted as falsifying observations rather than explained away. http://www.bio.fsu.edu/James/Ornithological%20Monographs%202009.pdf
The “favored hypothesis,” in this case, is that ha’adam (“the man”) was an actual individual.
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The math and simulations we are doing show it’s just fine to double every generation. With each couple having 4 kids. That is an annual growth rate of 1.2%, far lower that the ~3% inferred for long time spans amoung native americans. At that rate it is well beyond coallescent methods to detect.
I consider that explosive growth.
I’m not familiar with this estimate. Reference?
This is very quotable.
That’s incredibly useful, thanks.
I would certainly like to be proven wrong. Can you cite any pre-2000’s examples of creationists putting forward the idea that Adam and Eve were part of H. erectus in a time period of 200,000+ years before present? I am unaware of any such reference, but I hardly have a handle on all of the literature that exists from that time period.
Also, I doubt any YECs are putting forward the idea that any species existed 200,000 years ago.
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