john hawks weblog

paleoanthropology, genetics and evolution

Lower Paleolithic

  • Low-velocity spatter from the Neandertal palette

    Sat, 2012-01-28 16:43 -- John Hawks

    Paleolithic archaeology is the home of some of the best forensic work anywhere. I've often written about impressive analyses of stable isotopes, microscopic starch grains, phytoliths, and wear traces on artifacts. Among these, some of the most detailed studies involve the use of pigments by ancient people. Out of these, last week's paper by Wil Roebroeks and colleagues [1] really stands out by wringing every drop of information out of an ancient archaeological horizon.

    I wrote last fall about the pigment "workshop" at Blombos, South Africa, which is around 100,000 years old ("Blombos pigment workshop"). And some time ago I wrote extensively about pigment use among Mousterian-era Neandertals ("Pigment use and symbolic behavior in the Neandertals"). These kinds of studies face many challenges. If a mineral pigment has been used by ancient people, it will often exist in a site only in tiny pieces. At best, some accumulation of the mineral pigment might give an indication of intentional use by ancient people. In this case, the material was scattered in a dozen or so tiny droplets over a diameter of 15 meters.

    Mineral pigments have uses other than decoration. Sometimes they were used as part of a formula to make glue, which we can find still adhering to the back end of stone points. Ochre may also have been used in the process of softening animal hides. These uses were reviewed by Lyn Wadley [2], who has done more than anyone to uncover the ways MSA people processed ochre in South Africa. Pigments were used by humans as early as 200,000 years ago in Africa, and earlier than 100,000 years ago in West Asia (Skhul and Qafzeh [3]) and Europe.

    The new study by Roebroeks and colleagues extends the time of pigment use in Europe to earlier than 200-250,000 years ago, which is newsworthy. It is notable that this time is early enough to suggest that the common ancestral population of European and African archaic humans may have also used pigment (or have been capable of learning to use it given the right cultural or ecological conditions). But to me, much more interesting is the way the red ochre was discovered in the archaeological site, and the experimental replication of the process by which it was deposited.

    In the course of the archeological excavations, one of the sites, site C (excavated between 1981 and 1983), yielded 15 small concentrates of red material, with maximum size of 0.2–0.9 cm and 0.1–0.3 cm thick, with sharp boundaries to the sedimentary matrix (Figs. 1 and 2). The contrast in color between the bright- red concentrates and the yellowish-brown (Munsell soil color 2.5Y5/3) to grayish-olive (5Y5/3) sediment was striking (Fig. 2), facilitating recovery of these small, friable pieces at this site, excavated over an area of 264 m2 (Fig. 3). Although the red material has been interpreted as hematite (15, 23), these finds did not play a role in the history of ochre use, even though Maastricht-Belvédère became one of the flagship sites of Middle Paleolithic archeology, reviewed extensively in numerous textbooks (24).

    These hematite features are pictured in several ways in the article and supplement. They are tiny: here is one of them, on a piece of sediment that was removed in total from the site:

    Red ochre droplet from Roebroeks et al 2012 supplement

    Detail of Figure S4 from Roebroeks et al. 2012 supplement, showing red hematite concentration upon sediment fragment removed from site.

    It is simply remarkable to me that this excavation in the early 1980s uncovered an ancient sediment horizon using such great care that these tiny patches of red ochre were found. All were only a few millimeters in size. They were highly visible against the surrounding sediment, which helps to confirm that they don't belong there. Other aspects of the archaeology were likewise carried out meticulously. For example, the paper presents two refits of flakes and cores taken from the site, demonstrating that primary reduction of stone artifacts happened there with some products taken away from the site.

    The paper notes the lack of hematite in local contexts where people might have found it, arguing that it must have been imported from a distance of at least 40 km from a natural source. The archaeological presence of contemporary tools taken in the opposite direction toward that hematite source helps support this argument. Forty kilometers isn't terribly far for hunter-gatherers, but it is interesting.

    The experimental aspect of the paper is only sketched out in the text, and is described much more fully and illustrated in the supplement. Roebroeks and colleagues, looking at the small patches scattered across a diameter of 15 meters, guessed that they were a low-velocity spatter dropped from some kind of liquid. So they set out to reproduce it:

    We hypothesize that the best explanation is that the fine hematite material was originally concentrated in a liquid solution, and that blobs of this ochre-rich substance became embedded in the sediments during use of the liquid,spilled on the soil surface. To test this interpretation, we performed an experiment to observe the impact of drops of a hematite-rich liquid on the site C sediment (SI Text). Despite the limitations of this experiment, the similarity of the experimentally produced concentrates to the archeological concentrates at both macroscopic and microscopic levels is remarkable (SI Text) and lend support to our interpretation of how the material entered the sediment.

    The experiments are illustrated very nicely in the supplementary information for the paper. Here's one of the photos:

    Red ochre droplet experiment, figure S10, B from Roebroeks et al 2012

    Figure S10b from the supplement of Roebroeks et al. 2012. Original caption: "(A and B) Experimental hematite dots created on a 'smoothed' dry surface (50-cm height, 0.3-cm drops). The concentrates are within small craters produced during impact of the drops on the dry sediment."

    Their "hematite liquid" consisted of ground mineral combined with rainwater, "launched" from a height of a half meter. Sounds like something that should be for sale in a natural cosmetics store.

    What were these ancient people doing with liquid ochre? Good question. Given the unique care of excavation, the local context in which the mineral is highly visible in the fine sediment, I wonder how many other instances of similar deposits may have been lost over the years. It is sometimes excruciating to wait for results from an archaeological discovery, but the extremely slow and careful excavation methods do obtain results that could not be gotten any other way.

    I was privileged to see some details from another excavation this week, where even greater care is being taken. It's totally remarkable some of the things that are out there waiting to be found.

    References

    1. Roebroeks W, Sier MJ, Nielsen TK, De Loecker D, Parés JM, Arps CES, and Mücher HJ. 2012. Use of red ochre by early Neandertals. Proceedings of the National Academy of Sciences [Internet]. Available from: http://www.pnas.org/content/early/2012/01/17/1112261109.abstract
    2. Wadley L. 2005. Putting ochre to the test: replication studies of adhesives that may have been used for hafting tools in the Middle Stone Age. [Internet] 49:587 - 601. Available from: http://www.sciencedirect.com/science/article/pii/S004724840500117X
    3. D'Errico F, Salomon H, Vignaud C, and Stringer C. 2010. Pigments from the Middle Palaeolithic levels of Es-Skhul (Mount Carmel, Israel). Journal of Archaeological Science [Internet] 37:3099–3110. Available from: http://dx.doi.org/10.1016/j.jas.2010.07.011
    Tags: 
    pigment
    Neandertals
    experimental archaeology
    Middle Pleistocene
    Lower Paleolithic
    Synopsis: 
    A discovery of red ochre use by ancient Europeans before 250,000 years ago

  • 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, and Feibel CS. 2011. An earlier origin for the Acheulian. Nature 477:82 - 85.
    2. Roche H, Brugal J-P, Delagnes A, Feibel C, Harmand S, Kibunjia M, Prat S, and Texier P-J. 2003. Les sites archéologiques plio-pléistocènes de la formation de Nachukui, Ouest-Turkana, Kenya : bilan synthétique 1997–2001. Comptes Rendus Palevol 2:663 - 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, and Thouveny N. 2011. Early Pleistocene Presence of Acheulian Hominins in South India. Science [Internet] 331:1596–1599. Available from: http://dx.doi.org/10.1126/science.1200183
    2. Dennell R. 2011. An Earlier Acheulian Arrival in South Asia. Science [Internet] 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, et al. 2011. Late Acheulean hominins at the Marine Isotope Stage 6/5e transition in north-central India. Quaternary Research [Internet]. 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.

  • Australopithecus afarensis used stone tools

    Wed, 2010-08-11 15:13 -- John Hawks

    UPDATE (2011-09-06) Note: The conclusions of the research were later critiqued, I posted on that criticism after this post.

    Shannon McPherron, Zeresenay Alemseged and colleagues working at the Dikika field site in Ethiopia have found evidence of stone tool use 3.39 million years ago [1]. That's 800,000 years earlier than the previous first-known tool use, and occurs during the existence of Australopithecus afarensis.

    The evidence is a series of cutmarks and one percussion mark on two bovid bones. One is a piece of rib from a large "cow-sized" animal, the other a femur fragment from a smaller "goat-sized" bovid. The analysis goes through several microscopic comparisons to rule out alternative causes for the cutmarks, such as trampling. The key paragraph of the results:

    The cut marks demonstrate hominin use of sharp-edged stone to remove flesh from the femur and rib. The location and density of the marks on the femur indicate that flesh was rather widely spread on the surface, although it is possible that there could have been isolated patches of flesh. The percussion marks on the femur demonstrate hominin use of a blunt stone to strike the bone, probably to gain access to the marrow. The external surfaces of ribs have thin sheaths of flesh, so the scraping marks on the fossil rib suggest stripping off of these sheaths.

    I have some lingering doubts, none of which are very serious, but that point out the need to look harder at other sites. It sure would have been nice if they'd found an anomalous sharp-edged rock nearby.

    The two bones are compelling, but the study does not give much indication of how representative they are. How many similar-sized bone fragments were left at the site? How many were collected? What fraction of "cutmarked" bones does that make? What fraction show signs of trampling and various kinds of post-depositional damage?

    Those questions are essential to answer the "green car" problem. If you don't know this one, it's fairly simple -- a witness reports a green car leaving the scene, and green cars are very rare -- the police think this is a great lead. But blue cars are very common in the city, and there is a small chance that the witness mistook a blue one for a green one. Whether it actually was a green car depends on the actual proportion of green to blue cars, and the actual probability that the witness was wrong.

    In this case, I think there is a very small chance that the marks on these bones could have been produced by processes other than deliberate cutting by a stone tool. But in a sample of hundreds or thousands of bone fragments, a small chance might well happen a couple of times. It's very difficult to quantify this, because archaeologists don't collect every bone fragment. The only real way to address the problem is to find more cutmarks and do other statistics on them -- do they occur where flesh is attached to bone, etc.

    It does seem odd that nobody's identified clear stone tools, which are in later sites a lot more common than cutmarked bones. A tool-user will make many artifacts during her life. (Why "her"? Well, in chimpanzees, it's the females who dominate technology transmission...) We have a lot of australopithecine bones. If this was a long-lasting tradition, we should have found a lot of stone tools by now.

    Maybe it wasn't a long-lasting tradition. Chimpanzee technology is significantly clustered geographically, some of the most interesting behaviors have been observed only at a single field site. If Australopithecus had a similar pattern of cultural diversity, tool use may have been innovated many times without "catching on" over a wide geographic or temporal extent. Here's what McPherron and colleagues conclude along similar lines:

    Whether A. afarensis also produced stone tools remains to be demonstrated, but the DIK-55 finds may fit with the view that stone tool production pre-dates the earliest known archaeological sites and was initially of low intensity (one-to-a-few flakes removed per nodule) and distributed in extremely low density scatters across the landscape such that its archaeological visibility is quite low (16).

    Or maybe we just haven't noticed. Fluvial contexts may have been bad places for Australopithecus to hang out. McPherron and colleagues allude to this explanation for the local absence of tools at Dikika:

    However, stone tool production and consequently archaeological accumulations are not expected at this locality given the sedimentary environment characterized by the palaeo-Awash River emptying into a nearby lake (3, 4). In this relatively low-energy depositional environment, clasts suitable for stone tool production are not present (few particles larger than fine gravel, 8 mm diameter). Within the exposed SH Member, the distance from DIK-55 to cobble-sized raw materials (>64 mm) is ~6 km (at Gorgore; Fig. 1). Thus, in this instance the absence of evidence for stone tool production in the immediate vicinity of the cut-marked bones may reflect landscape-level raw material constraints.

    The research article is accompanied by an essay by David Braun reviewing the find [2]. He stretches a bit, but I think the interpretations he suggests are worth airing. One -- why are there cutmarked bones 6 km from any good source of stone raw material?

    The meat and marrow of large animals must have been a valued resource, because McPherron et al. conclude that the tool users incurred the cost of transporting stones 6 kilometres from where they occurred naturally to the site where the butchery took place. Further costs that were associated with the consumption of carrion, and were apparently worth the risk, include exposure to parasites and competition with large carnivores.

    Two -- what about the "meat-brain" connection?

    This provides exciting evidence of how A. afarensis behaved. At one time, the species was considered to be a relatively primitive hominin, but this perception is being redefined. For example, it now seems that Lucy's kin had body proportions that were more similar to those of humans than of apes (6). Analyses of the hand of A. afarensis show that it had relatively short fingers that would allow the kind of fine-scale manipulation necessary for tool use (7). A recently discovered skeleton from the Woranso–Mille area of Ethiopia suggests that A. afarensis did not have the ape-like, 'funnel-shaped' thorax usually associated with a large digestive tract and low-quality diet (8). Perhaps the findings that these hominins used tools and had a carnivorous component to their diet should not have been so unexpected.

    A 2.6-million-year-old butchery tradition should already have refuted the hypothesis that meat-eating caused the expansion of brain size in Homo. But it was still possible to maintain that the initial Oldowan was insufficiently dedicated, or that the anatomical specializations (e.g., small guts) allowing brain expansion took time to develop, or that as-yet-undiscovered large-brained hominins would be found. Any of these are still possible, but the observations Braun points out pretty much demolish the 15-year-old story of "expensive tissue." Australopithecus seems to have had a small gut, and a bigger brain than chimpanzees. If there was a tradeoff, A. afarensis had already made it.

    Braun didn't mention A. sediba, which adds another wrinkle. A late species of Australopithecus with human-sized teeth. Or (as some prefer), a pre-habilis species of Homo with an Australopithecus-sized brain. What was its diet like? I have a feeling we'll know before too long.

    Meanwhile, I'll be floating for the rest of the year, since I included this as the far-out "bonus" entry in my 2010 New Year predictions! You know, the one that's so bizarre that it seems like it'll never happen. Heh.

    UPDATE (2010-08-11): John Noble Wilford got ahold of some skeptics for his NY Times story on the discovery:

    Still, the discoverers are already being pressed to defend their interpretation that the cut marks on the bones are evidence of stone-tool butchery. Tim D. White of the University of California, Berkeley, one of the foremost investigators of early human origins, said flatly that their “claims greatly outstrip the evidence,” and noted, “We have been working sites in this area for 40 years, and not a single stone tool has been found in deposits of this antiquity.”

    Sileshi Semaw, a paleoanthropologist at Indiana University who was a discoverer of the oldest confirmed stone tools, from 2.6 million years ago, noted in an e-mail message from Ethiopia that researchers had often been misled by bone markings left by trampling animals and other natural causes. “I am not convinced of the new discovery,” he said.

    UPDATE (2010-08-12): Maybe some are looking for more about australopithecine diets. My post from 2005, "Chemistry and early hominid diets" has a good compilation of stable isotope observations and what may explain them. With the cutmark evidence, you can read through the discussion of C4 plant contributions, and think about the grazers that A. africanus may have been eating.

    UPDATE (2010-08-16): Science Friday with Ira Flatow covered this story last week, including commentary by Alemseged and David DeGusta, who suggests that the marks may be crocodile bite marks. Doesn't look like it to me, but as I wrote above, I'd like to see statistics on a few hundred damaged bones to see the probability that an arbitrary one will look like stone cutmarks.

    References

    1. McPherron SP, Alemseged Z, Marean CW, Wynn JG, Reed D, Geraads D, Bobe R, and Bearat HA. 2010. Evidence for stone-tool-assisted consumption of animal tissues before 3.39 million years ago at Dikika, Ethiopia. Nature [Internet] 466:857–860. Available from: http://dx.doi.org/10.1038/nature09248
    2. Braun DR. 2010. Palaeoanthropology: Australopithecine butchers. Nature [Internet] 466:828. Available from: http://dx.doi.org/10.1038/466828a
    Tags: 
    Dikika
    Lower Paleolithic
    Pliocene
    A. afarensis
    taphonomy
    archaeology
    Ethiopia
    Oldowan
    stone tools
    Africa
    zooarchaeology
    Synopsis: 
    A report finds cutmarks on fauna from Dikika, Ethiopia, 3.4 million years ago.

  • Mailbag: First Europeans

    Sat, 2009-12-19 13:35 -- John Hawks

    Regarding Lézignan-le-Cèbe:

    Now that's interesting. Few thoughts:
    1. Can you be more specific about the artifact skepticism?

    The question is whether they may be geofacts. If the ones pictured in the article are the best they have, out of a total of around 20, it's a fair question.

    2. Assuming it's real & it's about 1.6Ma, I think this has interesting implications about the initial Out of Africa expansion. It seems clear between this & Dmanisi that the earliest people in Europe did not have Acheulean technology. This leads me to two questions:
    A. Is the Acheulean really that superior to the Oldowan, in terms of straight up functionality? People have kicked around the idea that the handaxe might have been more important in terms of social interactions (i.e. the big handaxes as signs of competence/sexiness/whatever). I don't know enough about archeology to answer this question.

    I think we have to answer this with reference to the mechanism that causes Acheulean artifacts to be so widespread and persistent. This means not only bifaces but also aspects of procurement and other element of artifact reduction. It's easy to see why Oldowan is widespread and persistent: If you can maintain the idea of stone tools, knocking flakes off rocks, you've got Oldowan.

    But why bifaces? One possible answer is the same as the Oldowan -- they're really quite obvious. But if they were so obvious and easy, why didn't anybody make them earlier?

    My preferred explanation: They were functionally valuable, not too difficult, and were therefore recurrently invented again and again. This is the explanation for the fire drill in recent contexts -- independent invention. The test is whether there are non-biface aspects of the Acheulean that are too persistent to be compatible with independent invention. I don't know. Some obvious objections: If bifaces were so good, why were they ultimately replaced most everywhere? And why didn't they use them more often in East or Southeast Asia?

    Bifaces could be easier than we might suspect for another reason: Maybe there were genetic biases maintaining them.

    B. If the Acheulean is simply better technology, were humans really spread so thinly on the landscape at this time that they couldn't transmit a better technology across continents? If they were, it certainly highlights the appropriateness of source/sink models of human expansion out of Africa.

    I agree. The question is how hard were they to transmit? If we knew, we could say much about the demography.

    3. Assuming the site is legit & the Acheulean is plain better, does this have implications for the Out of Africa 2/Replacement model? The linchpin of that is that better technology allowed modern humans to once again expand out of Africa & replace the archaic peoples. But if ancient humans could expand out of Africa initially with nothing more than pebble tools, doesn't that seem to mitigate the logic of advanced technology facilitating a later expansion & replacement? Maybe the two out of Africa events are apples & oranges & this comparison simply isn't valid. (That is there was no one to outcompete initially, relative success is not a factor for the initial expansion.)

    4. Makes you wonder what else is in Europe at this early age.

    Don't forget Sima de Elefante. It's not as old, but it already raises many of the same questions. Was early European occupation constant? Was it an expansion out of Africa or Asia? Was it predictable as a consequence of Homo's ecology, or did it depend on some unique climatic conditions?

    5. Imagine they find hominin fossils. How much would you bet they're similar to the Dmanisians?

    Not too long ago, we had two options -- they were like Ceprano, or they were like Gran Dolina. Now Ceprano looks a lot less likely. And Gran Dolina, which gives us basically a face, isn't so awfully different from the Zhoukoudian faces. How hard would it be to derive these from Dmanisi? On the other hand, what do we know about the faces Africans after 1.5 million years ago? We've got OH 12 and Buia.

    Of course, we might predict that faces should be extremely variable, considering that the mandibles are. I'll be writing something about KNM-ER 1482 before long, which strikes me as an interesting case.

    Tags: 
    Lower Paleolithic
    Atapuerca
    Early Pleistocene
    Europe
    France

  • 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

  • Handaxes from under the North Sea

    Fri, 2008-03-14 10:58 -- John Hawks

    In case you needed a reminder that much of the territory occupied by Pleistocene humans is now beneath the waves, just take a look at this press release from the British archaeology company Wessex Archaeology:

    An amazing collection of 28 flint hand-axes, dated by archaeologists to be around 100,000 years-old, have been unearthed in gravel from a licensed marine aggregate dredging area 13km off Great Yarmouth.

    The find was made by a Dutch amateur archaeologist, Jan Meulmeester, who regularly searches for mammoth bones and fossils in marine sand and gravel delivered by British construction materials supplier Hanson to a Dutch wharf at Flushing, near Antwerp, south west Netherlands.

    The axes show that deep in the Ice Age, mammoth hunters roamed across land that is now submerged beneath the sea. These are the finest hand-axes that experts are certain come from English waters, although there have been a few finds on beaches, for example at Pakefield in Suffolk.

    As a result of the find, they moved the dredging operation to conform with regulations -- I suppose to preserve the site in case the sea level falls!

    It seems to me that these are likely to predate 100,000 years ago, but no date is really possible given the circumstances.

    This isn't the first such find. Werz and Flemming (2001) reported the separate discoveries of three quartzite bifaces during shipwreck archaeology in Table Bay, South Africa. Again these are undated but probably precede 300,000 years ago. Finds of artifacts from the later stages of the Paleolithic have been more common.

    References:

    Werz BEJS, Flemming NC. 2001. Discovery in Table Bay of the oldest handaxes yet found underwater demonstrates preservation of hominid artefacts on the continental shelf. S Afr J Sci 97:183-185.

    Tags: 
    Lower Paleolithic
    archaeology

  • Earliest stone tools on Java

    Mon, 2006-04-24 13:24 -- John Hawks

    The current Science has meetings reports from the Indo-Pacific Prehistory Association Congress, including this article by Richard Stone about excavations from Sangiran:

    At the meeting, archaeologist Harry Widianto of the National Research Centre of Archaeology in Yogyakarta, Indonesia, wowed colleagues with slides showing stone tools found in sediments that he says were laid down 1.2 million years ago and could be as old as 1.6 million years. The find, at a famous hominid site called Sangiran in the Solo Basin of Central Java, "opens up a whole new window into the lifeways of Java Man," says paleoanthropologist Russell L. Ciochon of the University of Iowa in Iowa City.

    This report is the latest in a series of finds from the site, which have been increasing in date:

    Over 2 months, they unearthed 220 flakes--several centimeters long, primarily made of chalcedony, and ranging in color from beige to blood red--in a 3-by-3-meter section of sand deposited by an ancient river.

    The find, not yet published, could be even more spectacular than Widianto realizes, says Ciochon. His team, which also works at Sangiran, has used ultraprecise argon-argon radiometric methods to date the volcanic strata overlying the levels excavated by Widianto to 1.58 million to 1.51 million years ago--making the flakes at least 1.6 million years old. If the flakes were undisturbed, Ciochon says, they would represent "some of the earliest evidence of the human manufacture of stone artifacts outside of Africa." Their antiquity would match that of the oldest flakes found in China, at Majuangou, dated to 1.66 million years ago and also made of chert.

    The article includes a picture of some of the tools, which are small flakes on a fine-textured material.

    The Sangiran flakes "are fundamentally different"--smaller--than the stone choppers made by H. erectus in Africa, says Ciochon. The evidence, he argues, suggests that Java Man had to range far for small deposits of good flint or chert and so created small, finely worked tools in contrast to the larger tools found in Africa.

    There certainly is a contrast in the absence of large core tools, but it would take a close study to show that the flakes are different. But if there was a conscious limit to the selection of good raw materials, that might be significant also.

    Tags: 
    Lower Paleolithic
    archaeology
    Homo erectus

  • Social vs. nonsocial information and Lower/Middle Paleolithic

    Mon, 2006-04-17 13:33 -- John Hawks

    On the basis of a couple of student questions, I think it's worthwhile to reflect a bit on where I am going with this (also possibly made more clear in this post, which covers learning more extensively.

    By definition, material culture is culture. From this, it follows that explaining regularities within (and among) stone tool industries is explaining cultural regularities.

    On the other hand, there is much more to culture than material culture. Material culture presents one facies of culture, but other aspects may have little to do with the material remains of tool use and manufacture. By extending our consideration of archaeology to the entire chaine opératoire, from the acquisition of raw materials, the process of learning manufacturing skills, and the ultimate use, reuse, and discard of the tools, we may hope that one or more aspects of tool-related behavior will at least touch on many other elements of social life. But still, tools may misrepresent the substance of culture as a whole.

    The problems understanding the whole culture at the Acheulean-MP transition are expressed by Belfer-Cohen and Goren-Inbar (1994:145-146, emphasis mine):

    Of the 2 my and more, which are assigned to the Lower Paleolithic, over 1.5 my are attributed to the Acheulean Industrial Complex (Isaac 1977,1986). The immensity of this time-span -- which is quite beyond our comprehension -- can be 'blamed' for our difficultures in assessing and interpreting various phenomena observed in the material remains from this period. Prehistoric research during the last few decades has focused primarily on issues such as hunting versus scavenging, mobility, camping, division of labour and sharing, etc. Thus the study of lithic assemblages has become of secondary and minor importance. For a while it seemed as if the lithic component constituting the majority of the retrieved material remains could not contribute any information towards resolving the issues detailed above. However, new approaches to the study of lithics, employing various methods of technical analysis and procedures such as multivariate analyses (Karlin et al. 1991) have led to a better understanding of lithic manufacturing processes (Boëda et al. 1990; Pelegrin 1993). The large body of data acumulated over the long term demonstrates that, through well-planned research, lithic assemblages can provide significant insights into the cultural complexity of prehistoric people (Gowlett 1984; Pelegrin et al. 1988; Pelegrin 1990; Wynn 1993a). Nevertheless, some researchers (usually those far removed from lithic studies) still demonstrate simplistic attitudes, such as referring to a single artefact type, or a single technological feature, as if it faithfully reflected the total material complexity of a Lower Palaeolithic culture. Thus Foley (1987) treated the biface as if it embodied the entire Acheulean tradition, and as such he opposed it to manifestations of Levallois technique, which he regarded as the marker of the Middle Palaeolithic 'Levallois-Mousterian' (p. 386). But not only do most Levantine Acheulean assemblages contain a Levallois component (Gilead 1970; Goren-Inbar in press, and references therein) -- which from the outset pulls the ground from under Foley's argument -- but the paper contrasts two entirely dissimilar, basically incomparable entities -- a specific tool-type and a particular production technique. Most important, the selection of a single component as the all-encompassing representative of a complex techno-typological tradition hinders the serious search for meaningful patterning.

    The "new approaches" mentioned here would be part of the "technological approach" discussed by Chazan (1997), reviewed in another post.

    After a due consideration of the technical aspects of the Lower Paleolithic industries at 'Ubeidiya and Gesher Benot Ya'aqov, Belfer-Cohen and Goren-Inbar (1994) concluded that the full technical repertoire of Acheulean people was complex and advanced. Quoting Pelegrin (1993), they write:

    It is of interest to note that Pelegrin (1993), in his detailed discussion of lithic production, refers to the process of biface manufacture as complex stone knapping. It involves '"a coherent critical approach" to the situation. It is also characterized by the construction of techno-morphological mental hypotheses and their evaoluation through the double filter of what is desirable and what is possible' (pp. 310-311). Summing up his observations, Pelegrin states that 'This operational competence is comparable with that of modern man in this technical context' (p. 313) (Belfer-Cohen and Goren-Inbar 1994:152).

    They draw this to an interesting conclusion:

    Perhaps we should not be surprised by the complexity observed in early lithic production. Applying the rules of 'General System Theory' (Bertalanffy 1968), we can compare the pattern discerned in the evolution of the lithic material cultures with that learned from Cambrian fossils about the history of life's evolution on earth (Gould 1989): 'The maximum range of anatomical possibilities arises with the first rush of diversification. Later history is a tale of restriction, as most of these early experiments succumb and life settles down to generating endless variants upon a few surviving models' (p. 47). In the history of the evolution of lithic production, too, we have the initial appearance of several production modes, used in a distinct fashion for the manufacturing of discrete morphotypes. Then, in later stages, for example the Mousterian cultures of the Middle Paleolithic, we observe a reduction in the number of production sequences and an increase in typological diversity (ibid:153).

    I view the situation rather differently. The maintenance of a cultural tradition of tool manufacture requires individuals to receive both the information of how to make the tools and the motivation to learn and make the same types of tools by the same process. Some information is acquired socially -- by watching others make and use the tools. Some information is acquired physically -- by attempting to flake stone and learning its fracture properties, for example. Likewise, some motivation is physical -- the need to cut something, while some motivation is social -- the need to produce tools that resemble the group's tradition, or that carry forward the signature of a teacher, for example.

    Without social motivations to maintain a tradition, individuals may have no particular reason to be receptive to the information that would allow the replication -- information concerning stereotypical reduction sequences and their outcomes. Physical motivations alone -- the need to cut something -- require relatively little in the way of social information.

    In a statistical analogy, the Lower Paleolithic may usually be interpreted beyond the number of degrees of freedom it actually presents. Bifaces, core tools, and flakes made on different raw materials and with different reduction modes are not necessarily evidence of complexity. Certainly a modern-day knapper asked to recreate each of the many combinations of tools and mode in an assemblage would have a complex task ahead of him. But thirty novice knappers asked to make each of several tools and given time to work with the materials would very likely come up with many different methods. In essence, our analyses might like to make some conclusion about "complexity", perhaps for interpreting cognitive prowess, but "complexity" is simply not a parameter relevant to the assemblages

    The Middle and Upper Paleolithic expresses some strong differences in tool types and manufacturing techniques across assemblages, along with greater within-assemblage consistency in technique. These two observations -- variability between and consistency within -- are sides of the same coin, since consistent differences between samples are impossible without consistent similarities within samples. They both arose because individuals were making more use of social information sources as they learned to make and use tools. Traditions are necessarily less recognizable when individuals acquire and use less social information in tool manufacture. Thus, more social information must lead to more recognizable and distinctive industries.

    Continuing the statistical analogy, the later industries present more degrees of freedom. There is more information to be explained in their production techniques, and the techniques themselves explain more about the lifeways and cognition of the makers. But what is to be learned is not mainly spatial or technical abilities, but instead attention to social information and motivations for maintaining social traditions.

    The point to the analogy is that the earlier tool traditions can say little about cultural systems, because the people show little evidence of having attended to cultural information in the context of tool manufacture. Even among chimpanzees, tool manufacture requires some cultural information -- observing other individuals using tools, for example -- and early humans must have had more social information about tool manufacture than this.

    And some aspects of early human tool manufacture do reflect social information. For example, raw material utilization clearly varies among sites:

    Figures 2 and 3 list the major tool types with the raw materials of which they were most frequently made (as can be seen in this inventory, the bifaces represent but one of several production sequences encountered at the site). Similar associations of specific kinds of raw material with specific tool types have been repeatedly identified elsewhere, especially in East Africa (Feblot-Augustins 1990 and references therein). In our opinion, these associations, which were found to be spatially and temporally transgressive at Ubeidiya, clearly attest to a continuous and effective process of information transmission. Such preference for certain selected raw materials within a given assemblage is a distinctive feature of the Acheulean, and can be viewed as indicating awareness of one or more of the following environmental potential, lithological properties or procurement logistics. Interestingly, the relative frequency of certain tool types does not seem to have been affected by the degree of availability of specific raw materials. Thus, while the scarcity at the site of limestone, for example, does not seem to have deterred the production of limestone spheroids and sub-spheroids, the abundance of basalt pebbles did not result in a higher production rate of basalt bifaces (ibid.: 150).

    But the use of social information did not dominate early tool manufacture. This means that the same functional items may have been repeatedly reinvented independently. A diversity of forms and methods reflects the primary use of nonsocial information in the learning and production of tools. Each individual worked with stone, probably upon observing others do so and use the tools that resulted. But they did not attend to the specific procedures used by other individuals, at least not beyond a point. Instead, each individual discovered much about flaking techniques and the physical properties of stone by himself (or herself). That repeated trial-and-error learning spread across many individuals explains the variation in reduction sequence in early tool traditions, the relative simplicity of end results, the use of a similar range of procedures on multiple raw materials, and the widespread lack of interregional or local variations. Some variations did exist and were persistent (i.e., East Asian lack of handaxes, woodland vs. nonwoodland in Europe). These may have reflected functional considerations oor persistent and widespread differences in raw materials (i.e. bamboo). But the East Asian case in particular begs for a solution that involves social as well as functional considerations, since bifaces to occasionally occur and might presumably have been useful for a range of functions that bamboo and simple choppers and flakes could not manage.

    In this case, there is some reason to see the biface not only as a functional implement but as an icon of its own manufacture. Social information is present in the form of the biface itself, to the extent that it is clearly recognizable as a product of human manufacture. A person might discover the way to replicate a biface, and even the motivation to do so if recurrently exposed to the shape and manufacture of them. Thus, the Achuelean tradition carries persistent social information, even if the ability of individuals to incorporate this social information was limited to the end product and basic fact of manufacture.

    It is tempting to interpret uniformity as requiring the repeated emphasis of certain kinds of information. But this interpretation assumes a human context in which many other kinds of social information are easily received and compete for attention. Students put their names repeatedly on assignments because of long reinforcement and adverse consequences for failure. This piece of information is emphasized to drown out the noise of other social information.

    But standardization and uniformity may equally be the result of limits to information transfer. We may imagine a society in which the only information that can be written is a name. In this context, it would be no mystery why there should be many objects that have names on them -- indeed, it is the only possible outcome. The biface may have emerged from a society much more like this one -- it was repeated because of the lack of other information, not because of a persistent reinforcement.

    As an aside, individuals who use lots of social information in their toolmaking procedures -- essentially, who learn to make tools by observing the precise steps that others use to make tools -- may not always imply that groups will arrive at different toolmaking traditions. There may be, after all, one best way to make tools, and different groups may arrive at similar methods semi-independently. But the observation that later technologies appear to become more consistent in their use of reduction sequences is strong evidence for the greater employment of social information irrespective of the appearance of regional or local variations. These variations may be a welcome confirmation of the model, but the degree of such variations cannot be predicted from it.

    References:

    Belfer-Cohen A, Goren-Inbar N. 1994. Cognition and communication in the Levantine Lower Paleolithic. World Archaeol 26:144-157.

    Noble W, Davidson I. 1996. Human evolution, language and mind. Cambridge University Press, Cambridge UK. Amazon

    Tags: 
    information
    archaeology
    society
    Lower Paleolithic

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