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paleoanthropology, genetics and evolution

Acheulean

  • Digging deeper into the earliest Acheulean

    Thu, 2011-09-01 01:00 -- John Hawks

    I've been ranting on Twitter all day about the new paper on the "earliest Acheulean" by Christopher Lepre and colleagues [1], published in Nature today. The first time I read through the paper, I really thought they'd miffed it. I mean, really, they published a paper on the earliest Acheulean artifacts without putting a picture of them in the paper.

    What actually bothered me more was the lack of any discussion at all about why the assemblage is Acheulean as opposed to, say, Developed Oldowan. The word Oldowan appears only in the context of saying that many localities within the same Kokiselei site complex have only Oldowan-typical assemblages. This started bothering me less as I ran through the citations to earlier work on the Kokilelei localities. But that raised another point of irritation: This Acheulean locality was briefly described already, a long time ago. Why is this news? And given that both descriptions are so superficial, where's the fuller account?

    I had to stop and think about why I was finding this all so irritating. I mean, it's a paper about dating an archaeological locality. It's a perfectly good paper about dating an archaeological locality, full of details about the local geology, methods of sampling and analysis. My reactions weren't a criticism of the paper, really -- although if you're going to write a high-profile paper about your site, maybe you should actually feature the archaeology of the site?

    I've been digging through references all afternoon, trying to get straight exactly why this paper doesn't mention the Developed Oldowan at all. I'm not saying I favor the Developed Oldowan -- just that we deserve some kind of thoughtful review of what constitutes an "earliest Acheulean" site. Is it a purely typological definition based on the presence of bifaces made on large flakes, or is there something more here? That's going to take me a bit longer to review, so I'll just report on some of what I found.

    This isn't news. Hélène Roche and colleagues reported on this locality in 2003, in Comptes Rendus [2], including a date range between 1.79 and 1.65 million years ago. They describe it as "without doubt, one of the oldest Acheulean assemblages in Africa." That's right, if you can read French, you're eight years ahead of Nature.

    This paper adds precision to the earlier estimate, and it's really important to do this well. But if you've been reading about the archaeology of Plio-Pleistocene Africa, finding a date of 1.76 million years for this locality with an Acheulean assemblage is totally expected.

    Roche and colleagues [2] provided only a short description of the KS4 assemblage. Even so, it's more than provided in the current paper by Lepre and colleagues [1]. Here is what the current paper includes about the assemblage:

    The KS4 assemblage (Supplementary Fig. 2) is characterized by the presence of pick-like tools with a trihedral or quadrangular section, unifacially or bifacially shaped crude hand-axes, and a few cores and flakes, all derived from the same mudstone bed. A single subsurface, in situ origin for KS4 is ensured by excavations at the main test trench that recovered several spectacular sets of refitted lithic artefacts (Supplementary Fig. 3). To the exception of a few cores made on basalt, the rest of the assemblage has been knapped from large cobbles or tabular clasts of locally available aphiric phonolite.

    The supplementary information does include photos of three bifacial artifacts and two refits. But there is no technical analysis of the artifacts beyond the paragraph above. There's not even a summary of the number of artifacts found at the site.

    Roche and colleagues added more details (my translation of the French):

    Kokiselei 4 is a highly eroded site in which a series of more or less extensive trenches (total 19 m2) were dug. Among these only one (KS4A) yielded in situ artifacts in sufficient numbers to form an archaeological horizon, with a vertical dispersion limited to only fifteen centimeters, and no faunal remains. Some objects, distributed in a more diffuse fashion, were found in two other test pits (KS4B and KS4C); these are lower in elevation than the main horizon. In parallel to the test pits, a systematic surface collection across 104 m2 (metric grid) was performed, which comprises the total sample of lithic material from KS4 (n = 167). It is characterized by robust, rough pieces of varying sizes, often very large, some scrapers and notches made on cobbles or flakes, by very large cores, by proto-bifaces or bifaces, and by picks with a trihedral section. Two thirds of the proto-bifaces or bifaces are manufactured on oblong pebbles, relatively flat, some quite large, whole or broken into two in the middle according to the major axis and very few retouched. Only a few are free of cortex and / or shaped enough to be called bifaces, the proto-bifaces in turn are made more coarsely, as if the concept of an elongated shape and sharp point was well integrated, but the operating scheme was inadequately implemented. All the tools characterizing a very early Acheulian are present, and it is to this cultural period that we attribute KS4.

    Roche and colleagues also described the other localities, all Oldowan, at a similar superficial level of detail. The conclusion that Acheulean and Oldowan were two industries overlapping at the same time in this area was suggested in that paper.

    That, obviously, leads to the real scientific story here. How could there be two different stone tool traditions overlapping across some fairly large area for more than 300,000 years? If we count Developed Oldowan, that makes three. Some people would count two Developed Oldowans A and B!

    I'm inclined to think that the scenario is false. These really aren't distinct cultural traditions. Archaeologists have created definitions of archaeological assemblages, and the definitions have changed over time. Initially the definitions were entirely typological -- you have a handaxe, you've got Acheulean. Over time, the definitions have become less typological and more inclusive of technical elements -- you make bifacial artifacts on very large flakes, you've got Acheulean. But these technical categories are not unique or necessarily difficult to invent, and may have been repeatedly invented in different groups, just in the way that different groups of chimpanzees have invented nutcracking and termite fishing methods. For these early assemblages, we don't have any way of telling who made what -- the only hominin fossils from Kokilelei, for example, are teeth of A. boisei. We don't know how many different kinds of hominins there were. Maybe there was only one.

    Early Homo is a bundle of mysteries, in other words, and the archaeology doesn't help. Can we make any sense of the development of early stone tool technology, from its initial beginnings to the handaxe-dominated assemblages? What does it mean that both Oldowan-like and Acheulean-like industries dispersed widely throughout the Old World? This is a really interesting scientific problem, involving information transfer, emergent sets of behaviors, invention and creativity, and their effects on survival.

    The paper by Lepre and colleagues discusses the problem of Oldowan and Acheulean coexistence briefly, reviewing the idea that Homo erectus may be tied to Acheulean, leaving open the question of whether more than one toolmaking species existed before 1.5 million years ago. The paper is noncommittal, but I would frame the question very differently. It's self-evident that Acheulean cannot have been a culture, because no human or animal culture exhibits its spatial and temporal properties -- appearing episodically across three continents over a span of 1.5 million years. The real question is whether we can make sense of the many different Acheuleans, and whether other Oldowans (possibly Developed Oldowans) might have similar heterogeneity. Asking whether an Oldowan-bearing population in Africa first dispersed to Dmanisi is begging the question.

    Finding these answers is surely a lot more interesting than what the press has done with this article.

    That's probably what irritates the the most about this: how boring the article and reporting seem to make this topic. When I did the Google News search this afternoon, there are no fewer than 165 news articles worldwide. Nature made its cover image this week a photo of one of the bifaces. You can't get much more of a press push than that for an archaeology story. None of the stories go beyond the very simple "oldest Acheulean" story. Now, I'm used to seeing the "oldest X" storyline a lot in paleoanthropology, it's a perennial favorite of journalists who can't think of anything more interesting to write. But in this case, it's the worst angle -- because it's the part that isn't actually news!

    References

    1. Lepre CJ, Roche H, Kent DV, Harmand S, Quinn RL, Brugal J-P, Texier P-J, Lenoble A, Feibel CS. An earlier origin for the Acheulian. Nature. 2011;477(7362):82 - 85.
    2. Roche H, Brugal J-P, Delagnes A, Feibel C, Harmand S, Kibunjia M, Prat S, Texier P-J. Les sites archéologiques plio-pléistocènes de la formation de Nachukui, Ouest-Turkana, Kenya : bilan synthétique 1997–2001. Comptes Rendus Palevol. 2003;2(8):663 - 673.
    Tags: 
    archaeology
    Early Pleistocene
    Lower Paleolithic
    Acheulean
    Oldowan
    Turkana
    West Turkana
    Kokiselei
    Kenya
    Africa
    Synopsis: 
    A paper reports on the earliest evidence of the Acheulean, but misses the key story.

  • Older and younger Acheulean in India

    Sun, 2011-03-27 00:37 -- John Hawks

    Shanti Pappu and colleagues [1] report on date estimates resulting from new excavations at the old site of Attarampakkam, India. The news element is that they date an Acheulean occurrence to as old as 1.5-1.6 million years ago. At the oldest, these dates would make the Acheulean in India equal in age to the earliest occurrences in Africa.

    The dates themselves depend on the decay of cosmogenic nuclides in the artifacts themselves. This is a kind of exposure dating -- as the artifacts are exposed to cosmic rays at the Earth's surface, they build up radioactive isotopes of beryllium and aluminum (10Be and 26Al), which have half-lifes of 1.39 million and 717,000 years, respectively. When they are buried deep underground, their exposure to cosmic rays stops, and the radioactive isotopes can only decay. Then the ratio of the two isotopes in the sample reflects the time since deep burial. But like other exposure methods, in practice this depends on a model of exposure time, burial speed, and radioactivity within the soil, which lends substantial uncertainty to the dates. The lower 95% confidence interval of each of the date estimates reported in the paper is still over a million years, leading to the minimal conclusion that the site is that age or older.

    Robin Dennell has written an accompanying short essay that gives a broader view of the Acheulian in South Asia [2]. The essay includes a great paragraph summarizing the now-obsolete idea that Acheulean reached India only a half million years ago:

    How does this new evidence affect our understanding of the South Asian Acheulian? Previously, the general consensus was that the Indian Acheulian was less than 0.6 to 0.5 Ma (5) and was thus much younger than that in the Levant (eastern Mediterranean). There, the earliest dates of 1.4 Ma, from ‘Ubeidiya in Israel, probably indicate a dispersal of hominins from Africa (6). A second influx of African immigrants is indicated by the discovery of African types of cleavers and hand axes at Gesher Benot Ya'aqov (GBY), in Israel, dated to 0.78 Ma (7). This evidence implied that the Acheulian dispersed eastward toward South Asia only several hundred millennia after it first appeared in the Levant. It also implied that the spread of Acheulian bifacial technologies into South Asia was broadly contemporaneous with its first appearance in Europe, where the earliest sites date from ∼0.5 to 0.6 Ma (8). Some have attributed this expansion of the Acheulian into South Asia and Europe to Homo heidelbergensis. This Middle Pleistocene type of hominin is known mostly from Europe, where it was first defined, but is also recognized by some (but not all) researchers at African sites such as Bodo, Ethiopia, and Kabwe, Zambia, and even at some sites in China (9).

    The "Homo heidelbergensis" model is in such utter disarray right now, I'm not sure many paleoanthropologists have realized the full extent of the problems. You should know that I don't believe in Homo heidelbergensis, never have. A couple of months ago, I was discussing some of the issues about mutation rate estimation with a very prominent geneticist, and the conversation turned to Homo heidelbergensis. What a shock the Denisova sequence should have been to those itching to see a H. heidelbergensis incursion into Asia!

    Notice however, the intrinsic nuttiness of archaeological interpretation. Oh, we have the first evidence for Acheulean in India around 600,000 years ago? Well, that's around the same age as the Bodo fossil from Ethiopia! What a coincidence! Maybe this new kind of hominin expanded from Africa and carried the Acheulean to India! And Sima de los Huesos is around 600,000 years old, too -- and there's a handax in the pit! My gosh, we need a name for those hominins!

    Well, the nice thing about a hypothesis built on mere coincidence, is that it only takes one observation to falsify it. Million-year-old handaxes in India ought to do it, and how. That's the message of Dennell's essay, and the subtext of the paper by Pappu and colleagues. What I find interesting is the extent to which the fact was hinted by earlier discoveries in South Asia but hampered by weaknesses in stratigraphic control and dating. From Pappu and colleagues:

    Sparse radiometric ages from sites in India have situated the Acheulian within the Middle Pleistocene, with a few dates suggesting an early Middle to Early Pleistocene age. However, these ages often exceed the limits of confidence of the methods used (2). They include an electron spin resonance (ESR) mean age of 1.27 ± 0.17 Ma, assuming linear U uptake, on two herbivore teeth from Isampur (23); an ESR age of ~0.8 Ma (lacking uncertainty envelopes) on calcrete from the Amarpura formation, Rajasthan (24), which has been correlated with the Acheulian site of Singi Talav (4); dates ranging from ~1.4 to 0.67 Ma for the tephra at Bori (Kukdi river) (25); and paleomagnetic measurements with evidence of reversals at the sites of Bori, Morgaon, Gandhigram, Andora, and Nevasa (26). However, the reliability of these ages has, in each case, been questioned on various grounds (5, 27, 28). Likewise, the age and stratigraphic position of artifacts and faunal remains from the Early Pleistocene Dhansi formation along the river Narmada are yet to be firmly established (29). Based on data from controlled excavations and two independent dating methods, our ages from Attirampakkam show that the Acheulian in India is older than previously thought. Evidence from other sites in South Asia should be reconsidered and redated.

    Much evidence already exists in the South Asian Acheulean that could be more accessible. The Acheulean in the region has been a long block of undifferentiated time, despite some very well-resolved sites. In addition to this much older dating for early Acheulean, India also has some of the youngest Acheulean assemblages anywhere -- for example, Haslam and colleagues [3] earlier this month reported on an Acheulean assemblage from around 130,000 years ago in northeastern India. That's long after the large biface tradition begins to give way to Middle Paleolithic and MSA toolkits in Europe and Africa.

    On the topic of Denisova, Haslam and colleagues were writing before that genome was reported. But they did know about the Neandertal genetic results, including the evidence of Neandertal ancestry within India. Nevertheless, they assert a scenario in which the makers of earlier and later Acheulean in South Asia are the same biological population, without substantial gene flow from regions to the west, including the Neandertals.

    Recent reports of the draft Neanderthal genome suggest that Neanderthals and H. sapiens likely did interbreed successfully soon after the latter had left Africa (Green et al., 2010), with the probable location of such contact to the west of India, in the Middle East. The southern limit of the Neanderthal range is unknown (Dennell and Roebroeks, 2005), but we emphasise that the continuity seen in the Middle Pleistocene South Asian technological record suggests that taxa derived from earlier hominin dispersals, and not Neanderthals, were the creators of the Indian Late Acheulean. Greater biological separation between dispersing humans and resident Indian hominins may have precluded viable genetic mixing (although see Liu et al., 2010 for an alternate view from East Asia), while similarities in certain technological strategies may have rendered cultural exchange a somewhat more likely occurrence.

    Well, the Denisovans didn't have to live in India when the ancestors of Melanesians ran across them and intermarried. But Denisova and the Neandertal genomes now make it very likely that the inhabitants of South Asia were one or the other. And even if South Asians were yet a third group, as yet unattested from genomes, it is no longer credible to suppose that they were isolated from Europe or Africa for a million years previous. The tools just don't have that much to do with the populations.

    References

    1. Pappu S, Gunnell Y, Akhilesh K, Braucher R, Taieb M, Demory F, Thouveny N. Early Pleistocene Presence of Acheulian Hominins in South India. Science [Internet]. 2011;331:1596–1599. Available from: http://dx.doi.org/10.1126/science.1200183
    2. Dennell R. An Earlier Acheulian Arrival in South Asia. Science [Internet]. 2011;331:1532–1533. Available from: http://dx.doi.org/10.1126/science.1203806
    3. Haslam M, Roberts RG, Shipton C, Pal JN, Fenwick JL, Ditchfield P, Boivin N, Dubey AK, Gupta MC, Petraglia M. Late Acheulean hominins at the Marine Isotope Stage 6/5e transition in north-central India. Quaternary Research [Internet]. 2011. Available from: http://dx.doi.org/10.1016/j.yqres.2011.02.001
    Tags: 
    Denisova
    India
    Lower Paleolithic
    Asia
    Early Pleistocene
    Late Pleistocene
    Neandertal DNA
    Acheulean
    Synopsis: 
    Long known from India, new papers are adding detail to the temporal extent of the Acheulean.

  • Handaxe beat

    Wed, 2009-09-30 11:50 -- John Hawks

    Julien Riel-Salvatore wrote recently about several handaxe stories, including the giant ones from paleo-Lake Makgadikgadi.

    By any standard, at 30+cm in length these things are frikkin' huge! Strikingly, the press release only mentions that these very large items were found, without any discussion of how their size is unusual and what this distinctiveness might mean. These specific artifacts are of uncertain age, and their function is also uncertain - at that size, it is unclear exactly what practical function they might have served, as they would have been rather unwieldy to use, unless they were somehow hafted, in which case their heft might be an indication of their ultimate function.

    Tags: 
    Africa
    Acheulean

  • The spotty Acheulean

    Wed, 2009-09-02 22:59 -- John Hawks

    Scott and Gibert report in today's Nature on the "oldest handaxes" in Europe:

    In Africa, large cutting tools (hand-axes and bifacial chopping tools) became part of Palaeolithic technology during the Early Pleistocene (1.5 Myr ago). However, in Europe this change had not been documented until the Middle Pleistocene (

    The "Anthro 101" version of the Acheulean makes it out to be a million-year-long technological yawn. The breakthrough of the first handaxes 1.5 million years ago led to a stultifying stasis. The handaxe was a "Paleolithic pocket knife" useful for many purposes -- but the advent of Levallois manufacture around 300,000 years ago consigned the handaxe to the midden of history. Except, of course, for scattered, benighted peoples who were still using handaxes up into historic times -- the exceptions proving the rule of bifaces' never-ending utility.

    Well, the Acheulean was boring, but it wasn't uniform. The Anthro 101 version makes Acheulean people sound too accomplished -- like they invented the bifaces and then started turning them out like industrial robots for a million years.

    Not so: Fine, finished bifaces tend to be less than 500,000 years old. They also tend to be European. Acheulean people didn't usually carry rock very far. With more sources of chert and flint, Europe's geology allowed a wider selection of fine handaxes than Africa's. That is, at least after 500,000 years ago or so. Before then, there just weren't very many handaxes in Europe.

    Here, Scott and Gibert suggest that maybe some other sites with "advanced" or "terminal" Acheulean may prove to be earlier than people now think. The two sites in this study were both initially thought to be much later -- for example:

    The youthful age (200 kyr old) assumed for Solana del Zamborino was largely based on its well-developed Acheulian lithic typology. Such a young age contrasts with our continuing lithostratigraphy and palaeoclimate research in the region, which indicates a final, major lake-forming event near the end of the Early Pleistocene (starting 800 kyr ago) and deposition terminating in the Baza Basin (600 kyr ago).

    They could well be right -- some European sites now thought to be late (post-500 kyr) might be earlier. What does that mean for our understanding of the Acheulean?

    Lower Pleistocene Europeans sometimes made finished bifaces, these were initially sporadic, and later became more and more common until the advent of Middle Paleolithic technocomplexes. The sporadic appearance suggests that people could live without handaxes, and that they were simple enough to be repeatedly invented. There's just not that much information content there, and groups of Early to Middle Pleistocene people arrived at the same solutions again and again.

    Technological "progress" is a misnomer before around 300,000 years ago. Early Homo made Oldowan (and Oldowan-like) industries that required few capabilities not mastered routinely by wild chimpanzees. Some, sure, but few. Bifaces require a bit more: a spatial conception of symmetry, longer action sequences. But Early and Middle Pleistocene people didn't carry it off all the time; they kept losing the biface outside Africa. And they kept hitting that biface mode. Curious.

    Other entries of interest:

    "Early Malaysian axes

    And then there was Levallois

    How monolithic was the Acheulean?

    Acheulean endings

    References:

    Scott GR, Gibert S. 2009. The oldest hand-axes in Europe. Nature 461:82-85. doi:10.1038/nature08214

    Tags: 
    Lower Paleolithic
    Middle Pleistocene
    Spain
    Acheulean
    stone tools
    Europe

  • Shell instead of stone

    Mon, 2009-04-06 10:53 -- John Hawks

    Discovery News has a short article about Australian archaeologist Katherine Szabo's analyses of tools made of shell instead of stone in Late Pleistocene contexts:

    In published research to date, Szabo reports having excavated shell tools dating back 32,000 years from a cave site in eastern Indonesia, and comparing them with stone tools from the same cave.

    "It transpired that the shell tools were in fact much more complex to produce than the stone tools," she said.

    The stone tools were randomly chipped, but the shell tools had been carefully chosen and shaped.

    In one case, a "cats eye" or operculum shell was flaked systematically with five blows, each one slightly overlapping with the last in a clockwise direction.

    I want to mention along with this story that one of our own Ph.D.'s, Kildo Choi, published a paper in 2007, "Shell tool use by early members of Homo erectus in Sangiran, central Java, Indonesia: cut mark evidence". That paper documented cutmarks on early Pleistocene faunal elements that were made by clamshell, not stone. So the use of shell as a raw material probably goes back hundreds of thousands of years in the area.

    Tags: 
    archaeology
    Acheulean
    Southeast Asia
    Late Pleistocene
    Indonesia

  • Knapping a handaxe

    Thu, 2009-03-05 10:00 -- John Hawks

    Science magazine's "Origins" blog is running a little feature by archaeology student Steven Goldstein on how to knap a handaxe.

    I’ve had a lifelong interest in archaeology, and to better understand the process of making chipped stone tools, I began teaching myself how to replicate them. I started with Oldowan tools and eventually moved up to Neolithic and New World materials. Here’s what I do, and what I think, while I make an Acheulean hand ax, which early humans created about 1 million years ago.

    On the same topic, I continue to recommend Tony Baker's site, which takes a practical view of stone tool production from the perspective of an experienced knapper. His Acheulean essay in particular is a thought-provoking exposition of the idea that handaxes were flake cores rather than finished artifacts.

    Tags: 
    teaching
    social
    Acheulean

  • Early Malaysian axes

    Sun, 2009-02-01 19:29 -- John Hawks

    I know nothing beyond the short press accounts about the 1.83-million-year-old "stone axes" from Malaysia.

    On the one hand, there's nothing inherently unlikely about it. Why not early artifacts in Malaysia, considering the 1.8-million-year-old Mojokerto from Java.

    You might object that it's too early to be a true handaxe, but the artifact pictured in the news article is not your typical Acheulean version, it looks more like one of the large bifacial artifacts that sometimes show up much earlier:

    On the other hand, the deposition scenario sounds a little wonky:

    The artefacts were found embedded in suevite rock, formed as a result of the impact of meteorite crashing down at Bukit Bunuh.

    The suevite rock, reputedly the first found in Southeast Asia, was sent to the Geochronology Japan Laboratory three months ago and carbon dated using the fission track dating method.

    Setting aside that fission track dating is not a form of radiocarbon dating, this still leaves problems. Fission track has a large standard error, and this doesn't make apparent how they know the artifacts are contemporaneous with this deposit. One of many reasons I'm glad I'm not a geoarchaeologist.

    Tags: 
    Bukit Bunuh
    Southeast Asia
    Acheulean
    Malaysia
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