Adult Proportionality in Small-Bodied Foragers: A Test of Eco-geographic Expectations

This study by Kurki et al. addresses the variations in body proportions of Later Stone Age (LSA) hunter-gatherers along geographic gradients and ecozones by comparing skeletal samples from different geographic areas and testing 3 hypotheses regarding the expected body proportions of LSA hunter-gatherers. The results are expected to follow Bergmann (1847) and Allen’s (1878) “rules”. Bergmann’s rule proposes that body mass increases in populations inhabiting cold climates. An increase in cellular activity results from the increased body mass therefore producing more heat. Allen’s rule proposes a similar thermoregulatory concept concerning a positive correlation between surface area, determined by limb proportions, and heat dissipation. Studies among human populations during the 20th century have demonstrated that Bergmann and Allen’s rules are applicable to human beings. Kurki et al. use eco-geographic studies to explain the relationship between 3 variables: (1) Latitude; (2) Environment; and (3) Human biological adaptations.

Samples
Sample 1. Khoe-San
Although sub-Saharan African groups are classified as being warm-adapted, low latitude populations, archaeological evidence suggests that the eco-geographic area inhabited by Khoe-Sans (descendants of the LSA hunter-gatherers who occupied the area) is significantly different. While the South African Cape is well below the North and South latitude division, the coastal climate is Mediterranean-like rather than tropical. The sample of 124 LSA hunter-gatherer skeletons (59 male and 65 female) from the Southern, Western, and Eastern Cape regions are dated between 240 and 7, 853 years BP.

Sample 2. Andaman Islanders
From the tropical monsoon climate of the Andaman Island, 31 proto-historic Andaman Island forager skeletons (16 male and 15 female) were collected. These skeletons date to around the mid 1800s and originated from the Greater Andaman Island which is situated between latitude 11° and 14° north.

Sample 3.
Kurki et al. use published literature to collect data representing skeleton samples from Northern and Southern Europe, North Africa, and Eastern and Western Sub-Saharan Africa.

Kurki et al. tested 3 hypotheses to explain the relationship between latitude, climate, and biological adaptations: (1) if the body proportions observed among LSA hunter-gatherers reflect those of populations inhabiting low latitude and warm climate regions (e.g. high limb to skeleton trunk ratio), LSA hunter-gatherers of the South African Cape inhabited similar environments; (2) if the body proportions of the LSA hunter-gatherers are similar to those of the European and North African samples, the LSA hunter-gatherers likely inhabited a Mediterranean-like climate; and (3) if the body proportions resemble those of the Andaman foragers and African Pygmies, LSA hunter-gatherers were adapted to warm climates. Although Andaman foragers and African Pygmies are relatively small-bodied populations, their bi-iliac breadth to stature rations are equal to those of non small-bodied warm climate inhabiting populations.

Materials and Methods
Kurki et al. calculated the brachial, crural, femoral, humeral, radial, and tibial indices and body breadth and mass to stature using the ratios in table 1.

Need to make space or else my post

Results
Limp Proportions:
Compared to the indices calculated for the 3 skeleton samples, the majority of the limb proportions of the LSA hunter-gatherers fall in between those of the North African and European samples.

Body Shape:
Proxy skeletal indicators were used to calculate stature ratios and the bi-iliac breadth determined the absolute body breadth. Kurki et al. found that body breadth decreased in relation to latitude, although the female African Pygmies have the largest bi-iliac breadth among the low latitude samples. Body mass also follows this trend, decreasing at lower latitudes. However, the Andaman Islander sample in which statures are similar to those of the African Pygmies have much more narrow bi-iliac breadths then expected. Sexual dimorphism was also observed in the LSA hunter-gatherer sample, although it was females who were generally larger then the males.

The results obtained in the study correspond to Kurki et al.’s third hypothesis. The skeletal morphology of the LSA hunter-gatherer sample falls between those of the European and North African Samples. Therefore, it appears that the Mediterranean-like climate of the southern African Cape had a greater influence on the LSA hunter-gatherer skeletal morphology than did the low latitude of the region. When compared to other African Sub-Saharan skeleton samples, the LSA hunter-gatherers and their descendants, the Khoe-San, have distinctly smaller limb proportions. From their findings, Kurki et al. caution against grouping populations into climate categories based on latitude. The eco-geographic patterning predictions on which Kurki et al. based this research was contradicted by the inconsistent body proportions of LSA hunter-gatherers and Khoe-San from the southern African Cape and the Andaman foragers.

Kurki et al.’s study of eco-geographic theories emphasizes that researchers consider the climate of regions inhabited by prehistoric populations. This is especially important when considering South African populations because the majority of archaeological sites are located on the coast. As demonstrated by Kurki et al., climates vary among and within latitudinal gradients. As a consequence, environmental adaptations may have developed for different climates then those predicted by latitude. However, the conclusions drawn from the study by Kurki et al. are based on methods that admittedly produce inaccurate results such as: “[…] the relationship between body mass and femoral height is not isometric, and the effect would be amplified in small bodied populations, such as those in this study” (p.30); There were several skeletons that were missing vertebral elements necessary to calculate skeleton trunk height. The height of these vertebral elements was estimated through a regression formula generated from a mixed-population reference sample which is rather problematic since the study sought to differentiate body proportions between populations; and only summary statistics were available for the skeleton samples obtained through published literature. Therefore, the samples were not directly comparable and a t-test identified differences in mean index value. The comparison of body proportions may have been somewhat altered. Finally, the indices and proxies for body proportions among different climates may be influenced by additional elements (e.g. life history parameters). Kurki et al. largely ignore the implications these additional elements may have on the body proportions of the sample populations in question.

Reference:
Kurki, H. K., J. K. Ginter, J. T. Stock, and S. Pfeiffer
2008 Adult Proportionality in Small-Bodied Foragers: A Test of Ecogeographic Expectations. American Journal of Physical Anthropology 136:28-38.

The Shape of the Neandertal Femur is Primarily the Consequence of a Hyperpolar Body Form

The Neandertal femur, when compared to anatomically modern humans, has distinctively larger articulations relative to absolute femoral length, a thicker rounded shaft, and a more obtuse angle between the femoral shaft and neck. In the early 20th century, when Marcellin Boule first described the Neandertal skeleton in detail, these distinct features of the Neandertal femur where attributed to a simpler social and cultural complexity which resulted in a high activity lifestyle. The author, Timothy D. Weaver (2003), notes that the assumption that elevated activity levels where consequences of Neandertal culture and social organization is unfounded because it is difficult to distinguish Modern Human from Neandertal cultures in the archaeological record. Although humans have the ability to buffer some environmental stresses through cultural adaptations, researchers now theorize that climactic adaptations account for the different dimensions of the Neandertal femur.

The theories now generally accepted by most researchers to explain different body dimensions within the same species were originally proposed by Bergmann and Allen. In summary, their theories state that “Endothermic species exhibit climate-related geographical patterns in overall size and body proportions” (p. 6926). Therefore, it is expected that humans inhabiting cold climates maximize heat retention though a lower surface area to body mass ratio, and humans inhabiting warm climates maximize heat loss through a higher surface area to body mass ratio. Cold-adapted humans generally have a small limb to trunk ratio, wider bodies, and reduced distal limb lengths. The “hyper-polar” or “hyper-arctic” body dimensions of cold-adapted Neandertals inhabiting glacial regions during the Pleistocene are most obvious in the absolute bi-iliac breadth and femur length relative to bi-iliac breath.

To determine if there is a relationship between femoral dimensions and climate induced body proportions, Weaver compares modern human males from different climates to fossils of Neandertal and near-modern humans (see tables 1 and 2 for sample summary). Weaver uses geometric morphometric methods to measure the overall hip dimensions of the 97 modern human males. These dimensions were calculated using 26 unilateral landmarks on the pelvis and 13 on the femur. The hip dimensions of Neandertal 1 and Skhul IV (near-modern human) were calculating using 13 unilateral landmarks on the femur. Because of fhe missing superior greater trochanter on the right femur of Spy 2, only 11 unilateral landmarks were available. Weaver’s results demonstrate that femur dimensions are correlated to climate induced body proportions. He found that:

“[i]ndividuals from cold climates tend to have relatively wide bodies as compared with individuals from warm climates… Cold adapted individuals have femora with large femoral heads and distal ends relative to length, thick and round shafts, and low neck; shaft angles; warm adapted individuals show the reverse pattern. These femoral changes are accompanied by pelvic changes. Individuals from cold climates tend to have wider pelvic apendatures, longer pubic bones, more flared iliac blades, more laterally pointing anterior-superior iliac spines, more anteriorly located iliac
tubercles, and more posteriorly rotated dorsal iliac blades relative to individuals from warm climates” (p.6927-6928).

Unfortunately, none of this is new information. There are also a few problems in Weaver’s testing methods which he does not address and have probably altered the results of his comparison. The most significant problem concerns Weaver’s disproportionate sample sizes. Weaver’s fossil sample, 1.75 (due to fragmentation) Neandertal femurs, and 1 near-modern human femur can not accurately represent populations. Although he uses only male femurs and pelvises in his modern-human skeletal sample, Weaver does not control for gender among his fossil samples, or age among any of the samples. Weaver’s calculations are also somewhat problematic as he uses 39 unilateral landmarks on the femur and pelvis of modern humans; however, he makes these same calculations from the fossil samples using only 13 (11 for the fragmented femur) unilateral landmarks only from femurs (not controlled for side, table 2). It appears that the only real value in Weaver’s test is in his comparison of femur and pelvic dimensions among modern humans inhabiting different climates. The sample of fossil Neandertal femurs used in Weaver’s study is too small to prove that the dimensions of the Neandertal femur are the consequence of a hyper-polar body form.

Reference:
Weaver, Timothy D.
2003 The shape of the Neanderthal femur is primarily the consequence of a hyperpolar body form. The National Academy of Sciences 100(12):6926-6929.

Sexual Division of Labor: To Cooperate or not to Cooperate?

Rebecca Bird’s “Cooperation and Conflict: The Behavioral Ecology of the Sexual Division of Labor” examines gendered differences in human subsistence behavior and attempts to provide ecological explanations for this division of labor that might be applied to human evolution and early hominid development. By exploring themes of cooperation and conflict in child-care provisioning, child-care constraints, reproductive goals, altruism and signaling, Bird concludes that cooperation alone does not maintain sexual division of labor but rather the conflict hypothesis is likely to maintain sex differences in subsistence.

The cooperation model suggests that by specializing in different resource acquisition, males and females are likely to maximize energy intake. David Lack suggested that a cooperative provisioning would ensure a higher reproductive success rate for both males and females. This is particularly true if resources are hard to locate. Lack’s hypothesis was based on the observation that nearly 90% of bird species participate in monogamous mating to insure stability in partnership (when insects were the primary diet base). In areas where resources are more easily located, an individual is likely to be self-sufficient and cooperation might collapse (67). It was eventually found that cooperation among the sexes for paternal care did not actually represent equal investment nor equal benefits. For example, male reproductive success is hindered by monogamy in that males have a higher variability than females. That is, males could acquire more fitness-related benefits by mating with more females. It is likely that a type of fathering that is less conflictual with reproductive fitness but less beneficial to offspring is engaged in. Bird argues that although female mate competition is rarely advantageous, if males control access to resources needed by females to reproduce (other than a new sexy pair of gametes), females might attempt to reproduce with many males in attempt to secure needed resources and might attempt to prevent their mates from mating with other females (67).

Bird argues that if sexual division of labor (SDL) results in specialization that would increase provisioning efficiency, three testable hypotheses emerge: 1) gender specialization would increase food going into the household in comparison to non-specialized cases, 2) male resource sharing should favor their own households, 3) men should have high payoffs for fathering in specialized cases.

Birds testable hypotheses are arguably geared towards the effects of specialization on males and male behavior rather than female behavior. What are some of the expected changes/differences in female behavior? Furthermore additional testable hypotheses include: higher success rates in subsistence acquisition (for example, in comparison to non-gendered specialized cases, or specialized males would have less success rates or greater energy cost-less efficient- in acquiring female-specialized resources and vice versa), greater variety in diet breadth and specialized tools.

Bird suggests that contrary to the notion that SDL would result in more reliable provision of food, Hiwi women have been found to contribute far greater than men. It has been shown that by participating in hunting, men loose out on the high returns that might be attained by aiding women in plant collection. Bird’s suggestion that Hiwi women contribute more than men goes against Gurven and Hill who claim that hunting is more productive than foraging where in the late wet season women who were pregnant and/or nursing collected 1,300cal/h, women not pregnant or nursing collected 1,600 cal/h and men collected 2,300 cal/h by hunting (although the reliability is not mentioned) (Gurven and Hill 53). Furthermore, Bird seems to equate caloric revenue as “contribution”. It should be noted however that women’s “caloric revenue” is mainly in the form of carbohydrates versus men’s “caloric revenue” include protein and lipids- both essential to human survival and functioning. Therefore, although women do not seem to gain calorie-wise in a specialized organization, they do in terms of the variety and essential nutrients provided by male contribution. Bird maintains however that even this need for a diversified diet does not explain why “sex differences exist… nor why it necessarily is men who obtain protein” (Bird 68).

Bird suggests that package size of acquired food plays a role in what and to whom food is shared with. She argued that “if big package hunting is primarily about fathering and provisioning, hunter-fathers must keep at least as much meat for their own households as they might if they had chosen small package hunting” (Bird 68). This does not seem to be the case with the Ache nor the Hazda. From this, Bird argues that costly hunting is engaged not because it provides for the family better but because it might “signal his quality as a mate or competitor” (71). The lack of evidence suggesting that providing meat gives male access to more sex leads Bird to suggest that the benefits of being a good under are indirect: the children of better hunters are less susceptible to mistreatment and infanticide and they are married to harder working women (71).

This however has been refuted by a recent study which suggests that hunters can and do influence or control distribution of meat. Kin, neighbors and cooperative partners are likely to receive a larger share of the kill as well as the nuclear family of the hunter. The hunter’s family has been shown to receive an average of 29.9kg/kill versus 13.5kg/kill which is distributed to other families (Gurven and Hill 54).

Furthermore, Bird states that “by hunting [males] can broadcast that skill to the large audience that is attracted to the kill. The fact that big game is shared is incidental” (72). This however brings into question the dynamics involved in large kills which are made successful by cooperation. To what extent do the men participate and how is individual skill recognized? How is more skill accorded to one hunter over the other and how does this get transferred from the kill site to the campsite? One would expect mechanisms that limit individual recognition or prestige to be in place when hunting is conducted in a group setting. How does this get altered when hierarchies (example chiefs participating in the hunt) are in place? It seems that signaling can only function if the group of males hunting allows for recognition of outstanding individuals, or if the group is composed of several hunting parties for attribution to a single individual is more likely in hunting of smaller game (which goes against the notion that hunting is costly behavior because of a lack of distribution control and physical danger).

Bird concludes that SDL will be stronger where males benefit more from investing in mating opportunities over provisioning ones.

Despite some data conflict with later published works, this paper is a good summary of the existing theories of SDL and gender specialization. It does however focus very heavily on an andocentric perspective of specialized subsistence costs and gains to the point where females are depicted as being acted upon, and simply having no choice in the matter. Females seem to have no choice but “cope” with the male’s preferred mating choices (to provide or not to provide?).

Also, it would have been insightful to provide additional ethnographic information that was not based solely on the Hazda or Hiwi.


Works Cited

Bird, Rebecca
1996 Cooperation and Conflict: The Behavioral Ecology of the Sexual Division of Labor. Evolutionary Anthropology: Issues, News and Reviews 8(2): 65-75.

Gurven, Michael and Kim Hill
2009 Why do Men Hunt? A Reevaluation of “Man The Hunter” and the Sexual Division of Labor. Current Anthropology 50(1): 51-74.

Human Social Evolution

Robert A. Foley’s “An Evolutionary and Chronological Framework for Human Social Behavior” examines the chronological framework and ecological basis for human social evolution. Foley argues that the combination of male kin-bonding and selection for energetically expensive offspring played a key role hominid social evolution and that this evolutionary path was not unitary or the consequence of a single event.

Foley maintains that although primatology, anthropology, and paleobiology have contributed behavioral and ecological theories to human social evolution, it is likely that “specific interactions between populations and their environment occurring cumulatively over millions of years”, rather than an inevitable evolutionary track, resulted in today’s observed human social behavior (96). Suggesting that the “particular times and … particular places [are] paramount”, Foley focuses on a chronological retelling of human social evolution. He suggests that human ‘sociality’ is a characteristic of anthropoid primates dating as far back as 35 mya and not a trait exclusive to humans (97). This is based on the argument that hormonal and biochemical mechanisms mediating behavior is similar across anthropoids.

The emergence of monogamy or instances of monogamy among anthropoids is associated with the inability for females to simultaneously have access to a resource base and a (undefined) “component of male contribution to infant survival” (99). According to Foley, monogamy is fairly unstable as if males are able to acquire more mates they will likely attempt to do so. Some primate groups have been shown to have various social states and are flexible within them. It is argues that this may have been the origin of social states which would have diverged with niche separation (99). In the development of hominids, however, an increase in infant dependency is likely to have affected the frequency of monogamy. Foley notes that an increase in infant dependency (as observed in chimpanzees) is typically dealt with by increased female kin-bonding which provides “allomothers”, lowering energetic costs for mothers. The lack of female kin-bonds in early hominid groups would have increased the importance of male-female bonds and food sharing.


This is supported by a distinct divergence between cercopithecoids and hominoids where the former show significant female kin-bonding and the later were likely characterized by “small social units made up of one male, one or more females, and young. It is suggested that the early diversification of Hominoidea between 25 to 20 mya was likely to have established the “small core units of homoid social life” of which gorillas, orangutangs and Gibbons are examples (100).

With the retreat of forests and the expansion of savannah grasslands, Foley argues that an increase in day range length, home range area and time for foraging was likely to have occurred due to the overall patchy dispersal of resources and increased seasonality. This is seen as a factor likely increasing the formation of small(er) social units and a strengthening of family bonds. (101-2). Although there have been disputes as to whether this was the ancestral condition (and that common chimpanzees departed from this model). The author proposes that it was likely an independent adaptation of the hominid lineage to open grasslands (102).

The increase in seasonality on the savannah is interpreted by Foley to have triggered an increased reliance on meat around 2 mya. This new reliance would further shift social relations and social structures such that this new behavior is different from australopithecine populations (102). The reason for this differentiation is not explained. This shift in diet is argued to have triggered an increase in encephalization , which consequentially would further alter human social behavior. Foley argues that for encephalization, being extremely costly, to occur and continue to develop there had to be positive selective pressures. The selective pressures for increased encephalization are argued to be “Greater meat-eating [as it] provided more energy, allowed for reduced energy expenditure, and acted as a selective pressure leading to greater levels of sociality” (102). This statement however relies on the assumption that during ecological changes gathering became insufficient and no longer provided the necessary calories and that hominids were skillful enough to hunt, kill, and butcher meat without expending more energy than attained (thus reducing energy expenditure). Also this suggests that encounter/success rates with prey were high enough to encourage increased meat consumption.

Foley further suggests that:

…during the period of 2.0 to 1.0 Mry the expected shift in social organization might well have been towards more intense and extensive male alliances…provided a premium in terms of foraging behavior under these new ecological conditions. Females associated with male groups that were numerically larger and effective at acquiring, and probably protecting resources (Foley 104).

This statement assumes that by 2-1 mya, males were the ones doing the hunting and that it was this male behavior that led to an increase in socially complex behavior. The notion that females would start to associate themselves with large male groups runs contrary to the small hominoid family unit previously argued by Foley. Also, this assumes that females were ineffective “at acquiring and probably protecting resources” and therefore had to rely on males (104). Changes in female behavior and therefore contribute to social complexity are ignored or are only discussed in relation or in response to male shifts in behavior.

Foley suggests that group size increased by 300,000 years BP to the point where grooming was no longer efficient for the maintenance of social relationships and therefore language emerged. The increase in brain size to 1000 grams during this time would have also prompted increased male competition and conflict between mating strategies as maturation of infants would have slowed and longer inter-birth periods would become characteristic (104-5).

The first 80,000 years of AMH is argued to not be characterized by social behavioral innovation but rather differences start to emerge around 40,000 BP and are not the founded in specific behavior but rather the propensity for dispersal which is argued to have come about as a result of increased hostility between males in male bonded kin-groups (106). As size increases, competition also increases and resulted in “demographic fission of communities” which would be composed of mainly kin-based groups (107). This is an interesting suggestion and would be consistent with fission of modern hunter-gatherers but the groups would have to maintain adequate genetic variability within the group or have a certain amount of inter-group exchange. The explanation of fission due to male hostility however seems incomplete and Foley ignores resource competition among other possible female conflicts (though it is not made clear if male hostility includes this).

Foley also claims that at about 30 kya, long-term evolutionary changes in behavior come to halt and are only reinstated with the beginnings of agriculture which require a “shift from small mobile hunter-gatherer groups to larger and more sedentary farming communities” and would have resulted in different social interactions and therefore a change in basic social structures (108).

The author maintains that the nature of social evolution must be considered similar to any other evolutionary process as one that is additive and that what we observe today is the product of individual elements. He argues that the “relationships between members of the same sex have remained more stable than relationship between the different sexes”. This is significant in that the author moves away from any type of biological determinism and suggests that male-female relations are flexible (and therefore existent unequal gender relations are not naturalized).

Finally, the author ends in summarizing the proposed “human revolution” theories of the Upper Paleolithic. These include language and symbolic thought. He stresses that “there is no clear anatomical boundary between archaic and modern” and “there is continual and regionally variable evolution in human cranial from 100-10kya” (113). Behavioral changes only become clear around 45 kya and this is restricted to Europe and the Mediterranean. This leads the author to suggest that symbolic expression was a regional phenomenon and not a reflection in change of “human global traits”. He claims that genetic diversification was not specific to the Upper Paleolithic but was present in both the Pleistocene and Holocene.

This paper presents a series of hypothesis for social evolution among early hominids and appropriately suggests that social evolution was not the result of a single event or drastic change. It is interesting that Foley suggests a regionally diverse hypothesis over a structural one. This paper was well argued though may have been more convincing if archaeological evidence was provided.

Works Cited

Foley, Robert A.
1996 An Evolutioanry and Chronological Framework for Human Social Behavior. In Evolution of Social Behavior Patterns in Primates and Man: A Joint Discussion Meeting of The Royal Society and The British Academy. W. Grunciman with John Maynard Smith and R.I.M. Dunbar, eds. Oxford: Oxford University Press.

Absolutely no TV until you’ve sharpened your biface...

Technological Efficiency and tool curation

Bamforth has acknowledged that tool curation is often defined in relation to its efficiency, but amid the multiple components involved in the activity, what is efficient is rarely specified. As stated in his 1986 publication, Technological Efficiency and Tool Curation, Bamforth seeks to clarify the notion of curation, assess several previous attempts explaining why curation occurs, and to present a hypothesis accounting for several important aspects of curation behavior.
Binford (1973, 1977, 1979) outlined two contrasting aspects of technological organization. According to him, curated tools are effective implements for a variety of tasks in which their structure has been designed with a particular function in mind. These pieces are maintained through numerous tasks, transported, and recycled when exhausted. To the contrary, lithic technologies based on expediency comprise manufactured tools, which are then used and discarded upon task completion. Therefore, curation should produce technologically sophisticated tools with formal distinctions designed to facilitate particular tasks, whereas expedient tools produce technologically simple assemblages portraying less patterned pieces.
Attempts to explain the occurrence of curation in the archaeological record, by both Binford (1973, 1977, 1979) and Torrance (1983), have lacked the specificity necessary to address the full behavioral complexity intrinsic to the process of curation. Binford links curation to subsistence-settlement organization, while Torrence attributes curation to the problem of scheduling different activities co-occurring in time.
Bamforth critiques these two stances with two simple explanations. He first criticizes both Binford’s and Torrence’s inability to address the full suite of behavior intrinsic to curation. Torrence’s definition’s failure to predict curation processes occurring after the initial design is its downfall, whereas Binford’s definition of curation encompasses an additional four aspects of stone tool manufacture. However, Bamforth recognizes that all five kinds of behavior need not occur in concert all the time. His example, that the flaked knives used as butchering tools in communal Plains bison kills were apparently manufactured in advance, resharpened, but then discarded, without being recycled, transported, or applied to other tasks beyond their primary function, indicates that different aspects of “curation” are circumstance dependent and that “no single measure of technological ‘efficiency’ can be universally applied to explain them” (P.39).
Ultimately, technology is structured by the requirements of an activity or set of activities that constrain variation in all aspects of tool manufacture and use (P.39). Technological efficiency appeases these requirements with minimum energy expenditure. Alternatives to extensive curation (i.e.: resharpening a dulled edge vs. discard and creating a new tool) are efficient only in the absence of sufficient raw material. Maintenance and recycling are thus closely related to raw material availability and not directly, as proposed by Binford, to settlement organization or the time limits, as advocated by Torrence, on the activities for which tools are used.
If processes of maintenance and recycling are a function of raw material availability, than a second major criticism is unveiled. Both definitions ignore local patterns of lithic resource availability, which inevitably places fundamental constraints on technology and subsequent curation processes. In light of this, Bamforth states, “we must examine these aspects of lithic resources in conjunction with the ways in which humans are or were organized to satisfy their other needs” (P.40).
Bamforth illustrates this response to material shortage using an example from the American Southern Planes. The Lubbock Lake site has hosted intermittent occupations over the past 12,000 years including significant Folsom, Plainview, and Firstview portions of the Paleoindian period.
The lithic assemblage is composed of three basic types of raw material, ranging from vey high-quality chert, to very low-quality silicified caliche. Bamforth’s hypothesis stipulates that maintenance and recycling rates should vary with access to raw material. Assuming distance to a source effects access, this range of materials should demonstrate varying rates of retouch (curation) depending on the distance between the source and the site. Therefore, tools manufactured from material originating in more distant sources should be subject to more frequent retouch in an effort to prolong its use-life.
In accordance with this hypothesis, tools manufactured from distant sources were subject to a high frequency of curation. In addition, based on their material, tools differed in their designated tasks. Durable but granular quartzites and cherts were predominately selected for wood work, while non-local stone, as expected, was used frequently for all tasks. In short, tools constructed from non-local materials were subject to higher maintenance and recycle rates reflecting their multipurpose nature. Bamforth acknowledges that the Lubbock Lake assemblage depicts a toolkit organization based on the different distributions and natures of the various sources of stone used to manufacture it (P.48).
The Lubbock Lake example affirms Bamforth’s original statement; that tool curation is a complex set of behaviors that cannot be explained by any single factor.

Bamforth, Douglas B.
1986 Technological Efficiency and Tool Curation. American Antiquity 51(1): 38-50.

Accumulation of Stochastic Copying Errors, Akumulation ov Stokastic Coppying Errrors, Akoomulajon ov Stokasic Coppyng Errrers

The Accumulation of Stochastic Copying Errors Causes Drift in Culturally Transmitted Technologies: Quantifying Clovis Evolutionary Dynamics. Hamilton and Buchanan, 2009.
This paper looks at the application of Eerkens and Lipo’s (2005) model on determining causes of copying errors that result in variation in material culture, and how different forms of cultural transmission or social learning affect the amount of variation. Eerkens and Lipo’s model basically seeks to predict the amount of variation given different factors and circumstances. Unlike Eerken’s and Lipo (2005) however, the Hamilton and Buchanan seek to determine not only frequency of variation but also its distribution through measuring the mean, variance, skewness and kurtosis.
Hamilton and Buchanan adapt Eerkens and Lipo’s model to analyze the variation found within Clovis point sizes, to determine if this variation is stochastic (random) or deterministic (result of biased selection). They also argue that this model can be used to track the movement of people across space and time, due to the drift effect of variation in Clovis point size.
Hamilton and Buchanan are particularly interested in drift “which is caused by population fluctuations and subsequent founder effects. A second source of drift is the accumulation of neutral, unbiased, but proportional copying errors through time.” (Hamilton and Buchanan 2009, page 55).
Hamilton and Buchanan term the first model the ACE, accumulated copying error model, which determines variation as a result of the accumulation of stochastic, imperceptible errors during transmission events. Thus the ACE is unbiased vertical transmission from a master to an apprentice. The Weber fraction explains that when humans try to make a copy of something without measuring it directly, their copy will vary by up to 5%. This difference becomes a source of variation which becomes compounded as copies of the copy (and so on) are produced with up to 5% copying errors at each generation.
From the ACE model, Hamilton and Buchanan develop the BACE model, which stands for biased accumulated copying error model. The BACE is similar to the ACE except cultural transmission in this case is biased.
Hamilton and Buchanan go on to create complex equations and simulations to test their models and the results of copying errors. First they test the ACE model, unbiased stochastic copying errors. Their simulation shows negative drift of the mean over time. Next, Hamilton and Buchanan test the BACE model, which is the biased accumulation of copying errors. They identify multiple sources of biased transmission. One of these is conformism where “each individual within a population chooses either to copy the most frequent variant, often given by the population mean […] a process akin to stabilizing cultural selection, […]or follow the rules of vertical transmission” (page 58). Another source of biased transmission is prestige bias, “where prestigious individuals influence social learning [because] each individual within a population chooses either to copy a prestigious individual […] or follow the rules of vertical transmission” (page 58). Here, prestigious individuals are skilled flintknappers from whom beginners would rather learn from. Like conformists, prestigious individuals and their followers are most likely to produce projectile points close to the mean variant. Both are analytically equivalent because the bias is towards the average variant, thus under biased accumulation of copying errors variation should be overall reduced. However copying errors still occur and result in negative drift of the mean. Thus it is predicted that projectile points should decrease over time at a slower rate than unbiased ACE.
The authors propose a case study on Clovis projectile points. The authors look at 232 points from 26 sites across North America. These sites are either caches, camps or kill sites. Also look at radiocarbon dates to determine time scale. This data shows their hypotheses to be true. They are as follows:
Hypothesis 1: frequency of distribution is lognormal as predicted by the ACE and BACE models.
Hypothesis 2: mean size of Clovis points decreases over time, as a function of distance from origin. Site type and raw material are non-significant factors.
Hypothesis 3: size of decrease in size caused by stochastic cultural transmission should be about 5%, as predicted by the Weber Fraction. Copying error accounts for about a quarter of the variation found in Clovis points.
Hypothesis 4: Variation should remain constant over time, suggesting variance is “bounded by transmission bias as predicted by the BACE model” (page 65). This highlights the relevance of biased cultural transmission is social learning.
Since the case study fits within the authors’ models and prediction, they argue it is strong support in favour of their hypotheses. Thus point sizes may be used as a tool for interpreting Clovis populations. They argue that the movement of people across North America can thus be found by analyzing average point size. Specifically the authors argue that by analyzing variations they can determine that Clovis populations were stable and spread rapidly while maintaining long distance social networks.
Furthermore, the authors conclude that the decrease in Clovis point size over time is a result of accumulated copying errors, and not a deterministic selection for smaller points. In other words, points got smaller because of errors in copying and not because smaller points were actually better for hunting due to ecological changes. That is not to say selection never occurred, but rather it simply wasn’t the main cause of the drift in mean size. Variance may have been reduced due to both conformist and prestige bias, due to the fact that the mean was probably the optimal form.
One interesting fact about this paper is that although the authors cite Eerkens and Lipo for the weber fraction figure, Eerkens and Weber say it is a 3% error while Hamilton and Buchanan say it is “up to 5%”, but never discuss where this difference comes from.
Despite this, the authors successfully applied Eerken and Lipo’s previous model, and expanded it. Use of these models in analyzing variation among artifacts can be very useful to archaeologists in interpreting hunter-gatherers behaviour. Use of these models can identify where variation is significant or not, and whether it is linked to particular types of cultural transmission. Furthermore, archaeologists may be able to interpret movement of populations over time. There are without a doubt other factors not accounted for by these models, including social relationships, skill level, etc etc, yet I think the models remain valid.
Clearly, research in evolutionary archaeology can result in new ways of interpreting data.


References:
Eerkens, JW; Lipo, CP. 2005. Cultural transmission, copying errors, and the generation of variation in material culture and the archaeological record. Journal of Anthropological Archaeology 24 316–334
Hamilton, MJ; Buchanan, B. 2009. The accumulation of stochastic copying errors causes drift in culturally transmitted technologies: Quantifying Clovis evolutionary dynamics. Journal of Anthropological Archaeology 28 55–69

Cultural Transmission, Copying Errors, and the Generation of Variation in Material Culture and the Archaeological Record. Eerkens and Lipo 2005.

In this paper, Eerkens and Lipo make a model to understand the means by which variation in material is produced. It is important to realize that here the authors are discussing variation among the same type of artifact, for example variability in thickness of the same type of ceramic pot or projectile point. They look specifically at copying errors as a source of variation, and how methods of cultural transmission either reduce, increase or maintain this variation. They have thus constructed simple models to quantify expected distribution of variation through time under different conditions. The authors claim their arguments can be extended to other aspects of human culture, although they never go into the meaning of this statement.

The authors discuss what produces variation. Although previous work has been done on the subject, it has focused on variation of types and not variation within types.

They begin by exploring cultural transmission, noting its difference with biological transmission, and thus the difficulties in tracking its complex processes.

According to the authors, variation can occur at different points in the creation of material culture in the archaeological record. There are: (1) transmission of instructions, (2) execution of instructions, (3) result of using different raw materials (Eerkens and Lipo 2005, page 319).
The authors propose a schematic for the generation of variation of material culture, which I have replicated here: (sorry about the bad reproduction, I had no choice but to up it up as an image)

The authors argue that the left and right column (stochastic and biased errors, respectively) create different kinds of variation patterns. Stochastic errors are compared to random mutations in genetic transmission, and therefore do not have a predetermined direction. This supposedly leads to smaller scale variation. On the other hand, biased errors, which are intentional, are greater and can be directional. This is because cognitive processes can “sort variation” (page 320). Thus when a hunter-gather wants to create a new form (ei: invent something new), it is not produced by random errors or from a blank slate, but with intentional modifications of a prior known (inherited) form that is believed to be an improvement.

However the authors are mostly concerned with the first column and variation as a result of stochastic copying error. They describe the Weber Fraction, a well known concept, which says due to the human threshold of perception; humans produce 3% error when copying something without being able to directly measure it. Thus we can expect a variation of 3% across a type of artifacts stemming from imperceptible human error. As the errors accumulate, they become perceptible over time, resulting in drift.

In their simulations, unbiased copying errors cause variation to be transmitted and increase over time, although the rate of increase slows down over time. They simulate biased transmission, notably conformist and prestige transmission. Conformist transmission means “individuals conform to the average value […] of the entire previous generation” (page 323). In conformist simulations, variance equilibrium is always eventually reached, although the time it takes to reach that equilibrium depends on the strength of conformity. Overall, this reduces the effect of drift. In prestigious bias, individuals are more likely to try to copy from prestigious flintknappers, which are assumed to produce variants closest to the mean. Thus, prestigious bias should reduce variance. However, prestigious individuals may not necessarily be producing traits that are closest to the means, and individuals may have to choose between multiple prestigious flintknappers, therefore drift is possible. Overall, biased transmission reduces variability caused by the accumulation of copying errors throughout time.

The authors then apply this model to two case studies. The first involves the basal width and thickness of Owens Valley projectile points. Since variation of basal width reduces over time, it suggests non-copying errors may be factors, in other words a biased transmission process may be operating. Thickness however, becomes increasingly variable throughout time, suggesting stochastic copying errors. The second case study involves Illinois Woodland Pot Sherds. Thickness remained constant over time, probably because thickness is important to the function of a vessel and thus non-functioning thicknesses would be weeded out. It would seem that a particular thickness was a trait that was selected for, thus drift was not caused by stochastic copying errors.

The authors admit in their conclusions that there are surely many other factors at play, including changes in settlement patterns, social organization, individual memory, concept of ideal form, etc. However copying error seems to be universal, and thus this paper provide us with a null hypothesis with which we can test data to determine the source of variance over time in the archaeological record.

I like that the authors created a null hypothesis. They build a model based on a universal human trait, and therefore can theoretically be used in any case study and is then very useful to archaeology.

I find it interesting that the trend of random error accumulating over time is the same as that in biological evolution with a rate of increase slowing down over time. The cause of this in biology is history; although here is always variation in traits of organisms, the extent of that variation depends on the organisms’ genetic history (Bell 2008). If this the same in cultural information, even though there are errors, a previous artifact from a long time ago is still remembered, even though it is not the one being copied? I think there are many implications of this that can be more thoroughly investigated.

Clearly, creating a theory of cultural evolution based on Darwinian evolution has many challenges, but as the authors have demonstrated, with more research in this area it is possible to build models appropriate for archaeology.

References:
Bell, Graham. (2008). Selection: The Mechanism of Evolution, 2nd edition. Oxford University Press.
Eerkens, JW; Lipo, CP. (2005). Cultural transmission, copying errors, and the generation of variation in material culture and the archaeological record. Journal of Anthropological Archaeology 24 316–334.

Neanderthals and Chimps and Cave Bears, Oh my!

Eric Trinkaus (1995). Neanderthal Mortality Patterns. Journal of Archaeological Science. 22, 121-142.

In his article, Neanderthal Mortality Patterns, Eric Trinkaus compares the mortality profile of 206 European and Near Eastern Neanderthals with 11 Recent human ethnographic profiles and two non-human species, finding an unusual patter involving too few infants and older adult as well as a very high number of adolescents and prime age adults in the archaeological record.

                  Trinkaus points out three palaeodemographic considerations to be kept in mind when attempting to discover demographic patterns through an examination of mortality profiles. He notes the difficulty of assigning age to any individuals in any society, but reasons that the use of life stage categories in the place of specific ages can mitigate this problem. He appreciates the prospect of sex and age biases generated through the taphonomic process, but adds that comparison to reference samples or demographic models can help to provide relevance. He also acknowledges that variation in demographic regimes can produce lineage affects, but argues that over enough time these distortions should average out. Despite these draw backs to basing demographic interpretations on age-at-death distributions, Trinkaus suggest that insights regarding paleodemographics can still be drawn.

                  Trinkaus employs six age categories to 206 individuals from 77 sites spanning from the Atlantic to Central Asia and from the Levant and Mediterranean Sea in the south to the Crimea and Belgium in the north.  He employs a time scale ranging from the last interglacial to the end of the early last glacial. Assuming that Neanderthals exhibited equivalent rates of maturation as modern humans, Trinkaus employs similar aging techniques in his comparison of this Neanderthal pool with mortality patterns from a set of ethnographic profiles of living ethnographic samples, one including foraging and horticultural groups, another composed of Holocene village foragers or horticulturalists as well as one prehistoric urban sample, and two additional groups of non-human species; Pan troglodytes –our closest relative, and Ursus spelaeus—a large bodied mammal from similar environmental conditions as the Neanderthals.

                  Through comparison of the various profiles, Trinkaus finds that both the non human chimpanzee and care bear patters parallel the Recent human samples, leading him to believe that the Neanderthal pattern should be comparable with Recent human samples. This closer comparison reveals some interesting similarities and variations, as Trinkaus finds that 80% of the individuals in the sample did not reach the age of 40,as well as a very high mortality rate among prime age adults and low number of neonates when compared to Recent human patterns.

Despite Trinkaus’ admission of the many difficulties in translating mortality profiles into paleodemographic data, as well as noting that such pattern may be more of a reflection of differing burial practices, he offers some implications of the study. Neanderthals appear to have had low life expectancies as adult, which in conjunction with the seemingly common phenomenon of healed injuries suggests a difficult life. He reasons that this low life expectancy would need to be countered with a high fertility rare, which would imply a demographic profile at or beyond the limits of Recent human populations (assuming stable population).

                  Trinkaus’ article both offers an interesting and exciting use of data in a creative way and makes very clear the limits of building paleodemographic data on related but indirect indicators in mortality profiles. His attention to the short falls of this extrapolation of data strengthens his credibility in interpreting his findings and suggesting possible implications. The only assumption made by Trinkaus that I felt remained unaddressed was his treatment of Neanderthal as homogenous, monolithic, and static. While acknowledging the distinctness in culture and economy of each Recent human population and how these lifestyles may affect demographics and mortality patterns, he lumps together Neanderthals in an extremely broad geographical area and time scale, offering no justification and making no attempt at consideration of regional differences. I would think that factors such as population pressures, environmental conditions, or even modern regional interests in archaeological research would be important factors in both the influence over and reconstruction of demographic profiles.

                 

 

Adding insult to injury, only burials for the contributors

P.B. Pettitt. Neanderthal Lifecycles: Development and Social Phases in the Lives of the Last Archaics. World Archaeology, Vol. 31, No. 3, Human Lifecycles (Feb., 2000), pp. 351-366.

 

             In her article, Neanderthal Lifecycles: Development and Social Phases in the Lives of the Last Archaics, P.B. Pettitt offers an interpretation of Neanderthal ontogeny and lifecycles in the context of the archaeological record in an effort to gain insight as to how Neanderthal individuals would have constructed their societies. She addresses this question in two parts, first presenting data on Neanderthal ontogeny and lifecycles, then constructing an interpretative vision of Neanderthal society.

            Pettitt undertakes a strategy of examining Neanderthal remains through categorization of individuals according to lifecycles phase, demonstrating that Neanderthals were subjected to considerable and habitual physical stress and exertion as well as inordinately high levels of physical trauma from a young age, noting a high preponderance of healed upper body insults, but near absence of survival after injuries impeding mobility. In her treatment of mortality, Pettitt notes that Neanderthal profiles differ from AMHs in their greater proportion of death at prime age, and relatively few examples of individuals surviving into old age. She attributes the infrequency of aged individual remains to a rarity of deliberate burials for this demographic as well as a similar trend regarding those under 4 or 5 years of age at death, seldom uncovered as single burials.

            In her reconstruction of Neanderthal lifecycles, Pettitt pays special attention to the high level of recovered prime adults, and this deficiency of aged individuals and singularly buried infants. She suggests this is a reflections of mortuary practices, which in the absence of evidence for complex verbal communication or abstract art serve as a medium for recognizing a social significance directly based on an ability to contribute to the group. She proposes that this ability to produce for the group constituted the basis for social organization, pointing to maturation and transformation through trauma as the two crucial factors in determining social worth. She identifies weaning, marked by independence and resulting heightened risk of mortality, as the point at which Neanderthals gain recognition as individuals of value. Sexual maturity completes this transformation as value is solidified through an ability to contribute to the hunt, reproduce, and provide for younger siblings. She hypothesizes that from this point on, death is recognized as a loss to the group and marked with a burial. Status as an individual of value can however be diminished or lost after sustaining debilitating trauma or reaching an age where contribution begins to decline. In this case death does not hold the same meaning of loss, and is therefore less likely to be recognized by the group. She points to a lack of healed lower body insults as evidence for the abandonment of injured individuals during travel, where their remains are less likely to be preserved.  Pettitt suggests that mortuary practices would only be performed so long as social value had been achieved and maintained up until the time of death.

            Pettitt’s framing of her article as ‘interpretive’ makes criticism of her arguments more difficult. The paper is well laid out and logical, but highly speculative as she reconstructs an entire social structure from a lack of evidence for developed verbal communication, a lack of evidence for symbolic art, and a lack of examples of deliberate burials for the very young and the very old. Attributing the deficiency of very young and very old Neanderthals to burial practices, or lack there of, is the basis of her entire argument. This is quite a leap of faith. The elaborate extrapolation of data is surely imaginative, creative and interesting, however I question how positive a contribution it is given the severe lack of supporting evidence involved, and near impossibility of proving or disproving a theory undetectable in the archaeological record. Pettitt’s narrative may very well strike closely to the true social structure and psychology of Neanderthals, but we will be hard pressed to ever evaluate its validity. 

Social Agency in Prehistoric Technology: A Critique

Marcia-Anne Dobres’ “Gender and Prehistoric Technology: On the Social Agency of Technical Strategies” attempts to provide theoretical space and methodology for studying gendered social agency of prehistoric technologies. Dobres tries to test the possibility and practicability of applying such a method by examining bone and antler technologies of the Upper Paleolithic. She concludes that Late Magdalenian tool producers not only solved problems but also expressed various social interests through material tool production.

 

Dobres stresses that the symbolic production of technology has long been downplayed by traditional considerations of tool production as “primarily about making and using raw materials” (27). She argues that the use and production of technology involves a complex system of interactions between social actors, expressions of social relations, and a re-creation of the social actor’s material world. According to Dobres, because technology relies on social relations of production, it is “a materially grounded arena for dynamic social interaction involved in the planning, production, use, repair and discard of material culture” (27). She argues that technology embodies cultural attitudes about production and use and therefore expresses a material manifestation of social ‘rules’.

 

She also discusses the importance of different macro and micro scale contexts of tool production. Macroscale refers to the environmental conditions and constraints imposed by nature on tool production as well as functional requirements of technology. Microscale context refers to the intimate daily interactions that occur during manufacture, use, repair or discard of the tool. Being the subject of Dobres’ study, microscale context reveals that different people will act differently towards one another depending on their relation to each other, the activity they are undertaking, and their location (29).

 

Dobres criticizes the traditional macro-regional study of traditional research on European Late Paleolithic artifacts and argues that they are too typological, transforming heterogeneous assemblages into homogenous artifact “types”. In attempting to find norms of technique, manufacture and morphology, traditional studies divide assemblages in “types”. This is argued to result in the studying tools “out of their original and archaeological contexts” (30). In order to overcome this, Dobres proposes a methodology that links production strategies to social relations in attempt to “infer the organizational dynamics of the concomitant production activities pursued at several sites” (31). She proposes a hierarchical system to study attributes of six different organic categories of artifacts. The data was subsequently organized along different axes: artifact class, morphology, raw material, inferred function, site-specific composite assemblage, and comparatively across regions (31-2).

 

Her results infer standardized shaft widths for harpoons, bone points and bone needles in morphologically similar zones with different types of deviation per site. That is, there are a variety of technical strategies employed to make, use, and repair the technology recovered. The variable patterning of shaft width at various sites suggests that function and raw material does not explain the differences observed (33). Dobres proposes that “gendered identities were an especially dynamic set of social relations intimately involved in the practice of Late Magdalenian bone and antler artifact production and use” and that the observed variability is “linked with gender relations through the social agency of technical strategies” (34).

 

The La Vache site was shown to have a significant amount of repair (20%) in comparison to neighboring sites. La Vache boasts a site-specific technique of harpoon base preparation (for hafting) as well as a great diversity in strategy for cutting harpoon barbs. Dobres attempts to understand how this variability in production relates to the diversity of the producers and how they might have positioned themselves throughout the production and repair processes. This, according to Dobres, can only be reached through a regional comparative approach. This led to analysis of the Mas d’Azil site, which reveals initial blank production as being the main technological process occurring at that site (repair being almost non-existent). This is argued by Dobres to suggest “a different intensity of social relations” and different “organization and dynamic quality of interpersonal relations of production…at these two sites” (39-40). She argues that gendered divisions of labor would have communicated, “power, rank and social status through material means and [through the] specific activities taking place” (40).

 

The regional variability found suggests flexibility in social conduct that varied according to the context. Dobres argues that if social mechanisms existed to control material and social rules of technological production (for example, tool production being ascribed according to gender, age or social position) there would not be evidence of technological variation to the degree found in the French Pyrénées (41). This would explain both regional variability in technique as well as degrees of variability across artifact types.

 

Finally Dobres argues that technological production served to produce more than material tools but also to establish and negotiate identity and social status/position. The production of tools also produces “gendered subjects” without necessarily attributing one artifact type or technical strategy to a gender (42).

 

Marcia-Anne Dobres provides an interesting and refreshing attempt to examine technology production within the conceptual framework of social identity and social agency. There are however several drawbacks to her arguments.

 

Although she attempts to provide definitions throughout her paper, they are scarcely sufficiently explained. They are often limited and redundant. For example, her definition of social agency “as a dynamic process involving acts of gendered identity, affiliation and differentiation” make statements such as “…studying the gendered social agency of prehistoric technology” redundant and unnecessarily confusing. If social agency by definition entails gendered identity, what or why is “gendered social agency” used? Is this something different form social agency?

Her attempt to argue for social agency in technology and tool production seem valid but becomes problematic when she defines technology in a way that “highlights the web interweaving the social, material and symbolic dimensions of material culture production”(26). She essentially attempts to argue something (social agency in technology) that is made true by virtue of a definition (technology as composed of social, material and symbolic dimensions). Although a technical detail, a series of similar tautologies exist throughout the paper. These confuse the reader into circulatory arguments that take away from some of the author’s valid points.

 

Dobres argues traditional Upper Paleolithic technological studies as being “narrowly typological” and focused on the “macro-regional trends and norms” (30). This might be argued to stem from a conflict in interests. Dobres is clearly interested in the social interactions and identities forged and negotiated through tool production. However, Upper Paleolithic technological studies are not as simplistic as Dobres seems to imply. It should be noted that the Upper Paleolithic is characterized by a surge in complex burials, the disappearance of H. Neanderthalensis and appearance of Anatomically Modern Humans (AMH). This greatly complicates the picture and adds significant weight on the importance of technological differences and artifact “types” as they may reveal a site’s inhabitants as well as traces of exchange or acculturation.

 

Her concern that site-specific composite assemblages are rarely studied is valid and would definitely handicap any conclusions made. Evidence of the extent to which assemblages as a whole are not studied by traditionalists is not provided and therefore her claim that such a critical holistic perspective is ignored seems unfounded.

 

It is questionable if Dobres’ methodology and technique of study is actually any different than that of traditional studies of technology. It is true that her methodology incorporates more components, but how many? And how well defined as her ‘empirical axes’?

 

Her only addition seems to be the inclusion of “site-specific composite assemblage”. She does not explain what “artifact class” or “artifact morphology” entails nor how it differs from artifact “types”. From a reader’s perspective, and without additional explanation, these seem identical. Furthermore, her criticism of traditional technology studies for employing or “aiming for” macro-regional analyses to discover patterns of production technique and morphology becomes confusing when she claims that “to make sense of technical strategies in terms of social actors requires comparative and regional orientation” (37). Is this not the same methodology? The difference not well explained.

 

Dobres does not provide specific information on the assemblage found at La Vache and Mas d’Azil nor does she discuss the distance between “neighboring sites”. The differences in activities and artifacts within the site have various possible explanations (for example different peoples, different function of sites, proximity to raw material etc.) but a lack of data makes the suggestion of anything other than what the author proposes impossible to found. Furthermore, little stratigraphic information is given and the “variety” found at the sites is not clearly defined as being found in a single layer. Information regarding the integrity of stratigraphy is not provided nor is the number of occupations.

 

The use of the word “gender” throughout the paper seems irrelevant. She largely argues for social agency, which includes acts of gendered identity (among other things), but yet distinguishes gendered identity throughout the paper (by explicitly using the word gender) from the other components of social agency. This is contradicting and confusing as it seems to step away from the holistic social perspective that she initially attempts to provide and openly criticizes traditional technological studies for not doing. Furthermore, she asserts that gender played a specific role in the dynamics of tool production yet she does not explore that role nor does she link it to her evidence.

 

Finally, although she provides an interesting take on technology production, it is questionable if any of her assertions are actually novel to archaeology. Her criticism of traditional technological studies seems to suggest that there is a serious lack of in-site composite assemblage study and how this reveals differences in social agency. But did archaeology every really doubt social agency in tool production? Regardless, Dobres’ attempt to bring social agency to the forefront of her research and insuring that it is not forgotten is appreciated- despite some of its drawbacks.

           

Works Cited

Dobres, Marcia-Anne

            1995 Gender and Prehistoric Technology: On the Social Agency of Technical             Strategies. World Archaeology 27(1): 25-49.

 

Middle to Upper Paleolithic Transition = Stoopid

O. Bar-Yosef (2004). Eat What is There: Hunting and Gathering in the World of Neanderthals and their Neighbours. International Journal of Osteoarchaeology. 14: 33-342.

 

In his article, Eat What is There: Hunting and Gathering in the World of Neanderthals and their Neighbours, O. Bar-Yosef briefly summarizes and offers a generalized critique of three current hypotheses regarding the Middle to Upper Paleolithic, arguing that humans hunted, gathered, and scavenged what was available in local contexts.

Bar-Yosef begins by outlining some of the limitations imposed by the archaeological data set, focusing specifically on the problem of reconstructing diets, economies, and mobility patterns in the absence of critical data regarding plant food. He also stresses the fact that many trends we see in ethnographic accounts of hunter-gatherers were not necessarily present before the Holocene. Fish did not appear to be a major dietary component until this time, and the ethnographic record is devoid of hunter-gatherer occupation in temperate regions now dominated by sedentary groups.

The author follows his mention of broad problems of constructing Paleolithic environment with a brief outline of three current hypotheses explaining the Middle to Upper Paleolithic transition. The first explaining the change as resultant of gradual behavioural and cultural changes, the second citing technological advancements as a response to specific environmental changes in a core area enabling a dispersal of homo sapiens sapiens and their impact on neighbouring populations, the third attributing the transition to a fundamental neurological change which allowed for greater behavioural flexibility.

The author then shifts to a focus on Middle and Upper Paleolithic hunting, pointing out that older visions of Neanderthals as strictly big game hunters or scavengers have been generally discarded. He contends that there was essentially no difference between the Middle and Upper Paleolithic, and that this comparison should be discarded in favour of analysis based on smaller and standardized time units and more localized regional conditions. Bar-Yosef concludes by stating that current research indicates that faunal assemblages are representative of what was locally available to hunters, and that any deviation from this pattern warrants further investigation of the discrepancy. He also suggests that future research needs to break from a Eurocentric study of the transition, incorporating a wider context by testing theories against data from other regions of the Old World.

Figure 1. Diagrams always make arguments look more scientific (Bar-Yosef 2004)

Bar-Yosef’s overview of the Middle to Upper Paleolithic transition was extremely broad and shallow. No specific arguments were aimed at any of the three theories he introduced at the beginning of the paper, nor were they elaborated upon because such would be “beyond the scope of this paper.” Leaving me to wonder why they were mentioned at all. The problems outlined were diverse and involved little depth, reading like a to-do list rather than offering any insights or clear issues for consideration. Anyone with enough background in Paleolithic archaeology to know what Bar-Yosef was talking about would not find anything new or interesting in the paper while anyone without such experience was not given enough context to figure out why or how such issues were problems. Without any clear direction or objective in the paper other than to list off problems with constructing Paleolithic conditions or comparing Middle and Upper Paleolithic economies, the paper struggled to maintain cohesion. What I learned from this paper is that you can’t really compare ethnographic accounts with Paleolithic hunter-gatherers, you can’t really tell what Paleolithic hunter-gatherers ate or how they moved around because of the lacking faunal data, you can’t really construct broad theories because local conditions are what’s most important, and the three hypotheses that exist to explain a Middle to Upper Paleolithic transition aren’t very useful because their frames of reference are flawed. The only real question that I was left with after reading the paper was if there is any point in looking at the Middle to Upper Paleolithic transition at all.

 

When in doubt, map it out

Jordi Serangeli & Michael Bolus, Out of Europe – The dispersal of a successful European hominin form. Quatär 55 (2008): 83-98

            In their article, Out of Europe – The dispersal of a successful European hominin form, Jordi Serangeli & Michael Bolus map the geographical distribution of Pre-Neanderthal, Early Neanderthal, and classical Neanderthal remains in an effort to discover a core area of Neanderthal occupation. By mapping 183 sites, the authors discern southern Europe as a core area of continuous occupation. They postulate that this region served as a launching point of subsequent dispersal into the Near East and central Asia. In conjunction with the assertion that Neandertals evolved in relatively warm southern Europe, Serangeli and Bolus refute theories of Neanderthal cold adaptation, attributing the presence of Neanderthal remains in cooler climates as only peripheral to this warmer core region.

            The authors point to an absence of ancestors with Neanderthal traits outside of Europe as key evidence for Neanderthal evolution taking place on the continent in isolation from other humans. Through analysis of their map, the authors distinguish southern Europe as the area where Neanderthals lived continuously and exclude northern and central Europe for the fact of depopulation during glacial periods.

Serangeli and Bolus support their hypothesis of Europe specific adaptation with various bit of evidence, attributing Neanderthal morphology instead to requirements of high mobility and close contact hunting strategies. Among their southern European adaptations they point out that no other major extinctions accompanied Neanderthal expansion, citing a low population density adaptation as a contributing factor. They also describe the low number or bone and antler artifacts as a result of heavier reliance on wood tools, readily available in warmer southern Europe, as well as a lack of dwelling structures and heavy footwear, both less crucial in the south. The fact that Neanderthals survived longest in southern Europe is also pointed to as evidence of their being most suited to this region.

(Serangeli & Bolus 2008)

Serangeli and Bolus also address the question of whether Neanderthals, in their expansion “Out of Europe” meet Anatomically Modern Humans expanding Out of Africa, suggesting a situation of alternating occupation, not coexistence. In agreement with their Europe adapted view of Neanderthal evolution, Serangeli and Bolus suggest the Neanderthal occupation in the Near East occurred during cooler, more humid periods, reminiscent of southern Europe conditions, vacating the region during warmer, drier times when AMHs moved in. A similar reaction to less favorable conditions is suggested with regards to the vacation of northern Europe. While AHMs eventually replaced Neanderthals in Europe, the authors point out the opposite appears to be true in the Near East.

Serangeli and Bolus’ use of mapping in order to uncover a core Neanderthal region is a logical and natural step in the quest for answers regarding Neanderthal evolution. The clean and straightforward methodology is easy to understand and difficult to argue with, it is quite persuasive. The authors do however make a broad assumption regarding the completeness of the data and presume the pattern uncovered through excavation truly reflects Neanderthal populations despite an acknowledgement of uneven interest in Paleolithic archaeology across the continent. Using an absence evidence for bone/ antler tools, hard footwear, and shelters in northern Europe as evidence for southern adaptation is not the most rock solid line of argumentation, but given the general paucity of such data it can be forgiven as support for a well laid out map.

The grass is always greener on the other side

Modelling Paleoindian dispersals

The primary hindrance to the rapid dispersal of early Paleoindian populations in the terminal Pleistocene was the influence of habitat variability. Steele et al. present a demographic simulation model in which rates of spatial range expansion are measured with the assistance of the mapped reconstruction of North American vegetation coverage.
The rapidity of the southward expansion is explained archaeologically in two contrasting scenarios. The first model stipulates one or more late glacial dispersals occurred, characterized by far ranging expanses and rapid population growth. This model implies archaeological material represents a sudden appearance characterized by an increase in artifact densities on a continental scale. The second scenario states that multiple, slower, colonization events occurred defined by low rates of population dispersal and slow population growth. Therefore a gradual increase in the archaeological remains observed in the cultural record occurs.
The archaeological data supports the first model, but taphonomic biases and sampling strategies conflict with the identification of the earliest occupation remains, confounding attempts to elucidate both models. Steele et al. suggest the contribution of paleovegetation reconstruction will optimize the prevailing scenario of a late glacial Beringian colonization of the Americas.
Ethnographic observations indicate hunter-gatherer densities vary according to habitat and therefore it becomes imperative that the paleohabitat be the primary variable in the simulation of population densities for Paleoindian colonizers. Evidence for the reconstruction of the Pleistocene environment is derived from numerous lines of evidence. The most direct evidence comes from fossil remains of vegetation, which provide a diagnostic indicator for particular vegetation zones (Ex: boreal forest, grassland, etc…). Additional sources of data include sedimentological indicators; soil types containing trace elements of overbearing vegetation coverage, and animal fossils; indicating which animals exploited a particular niche and its co-occurring vegetation coverage.
Naturally, the greatest uncertainty in the reconstruction of Pleistocene paleoenvironments in North America occurs for the older time frames and the most accurate, developed with the most samples, occur after 11,000 years.

Figure 1. 13,000 radiocarbon years ago.
Following the last glacial maximum, by around 14,000 BP, a significant warming and moistening of the climate occurs. However, throughout much of southern North America, cold and dry conditions appear to have endured. Nevertheless, continual glacial retreat carved an ice-free corridor although not to the extent that its entire length was navigable; glacial lakes inundated much of the interior.

Figure 2. 12,000 radiocarbon years ago.
Boreal forests had spread throughout much of the western lowlands indicating the continued effects of warming and moistening. By this point, the receding glacial wall had revealed a much wider corridor but still presumably impassable on account of vast lakes of meltwater.
Induced by the warming climate and moist conditions, short grasses crept over much of the desert conditions of the Great Plains.

Figure 3. 11,000 radiocarbon years ago.
This period coincides with the Younger Dryas cold shift inducing a brief reversion to cold and arid conditions. Rising sea levels severed North America from Eurasia while the ice-free corridor at last opened extending some 500 km in width permitting passage.

Figure 4. 10,000 radiocarbon years ago.
The Younger Dryas concluded shortly after ushering in vast expanses of forest throughout much of North America save for the plains and the western basins. In the North coverage was patchy, creating a forest-grassland mosaic.

This paleoenvironmental reconstruction permits observation of the effect of variation in the continental landscape on predicted Paleoindian occupancy rates. This is aided by a map developed by Faught, Anderson and Gisiger (1994) compiling 10,198 incidences of Paleoindian projectile points over the landscape throughout the continent. Inferred from these point locations along the landscape are the regions occupied during the terminal Pleistocene by initial Paleoindian migrants.

Although this projectile point compilation is an incredible asset to Paleoindian mobility research, it is a large assumption to accept that mapped artifact densities reflect actual deposition and not variability in recovery rates. A glimpse reveals the highest concentrations of Paleoindian projectile points are located on the east coast of the United States, the most densely populated region subject to the most modern landscape development. Although this very well may be a valid depiction of Paleoindian dispersal patterns, the possibility that it is the product of an extreme sampling bias cannot be ignored. Any analysis of Paleoindian mobility and dispersal must take this into account.

Based on the mapped deposition of projectile points and the reconstructed paleovegetation coverage of North America, Steele et al. conclude that population mobility and growth were constrained by the vegetation structure in the terminal Pleistocene. However, this model is complicated by how capable of adapting to the available resource structure early colonists were.

Steele et al. make a bold assumption that the Early Paleoindian populations were initially highly adapted to the resource availability of each new habitat zone. Despite this assumption, the trend indicates an extremely rapid adaptation in light of the significant increase in population density as inferred from larger and more sites and denser artifact assemblages. Although the assumption that Paleoindians entered the New World preconditioned to the new lifestyle is unreasonable, their ability to adapt so rapidly should not affect the results of this study, despite the intrinsic assumption.

Steele, James, Jonathan Adams, Tim Sluckin
1998 Modelling Paleoindian dispersals. World Archaeology 30(2): 286-305.

The Walrus and the.... Paleoeskimo?

The immediate, short-term effects of a sudden prosperity are visible and well understood; exploitation increases, mobility patterns are adapted to the new resource, and social or cultural factors often follow suit. Meribeth Murray describes how a short-term abundance of walrus caused long-term changes in the socio-economic system of the Dorset Paleoeskimo culture that persisted into the Late-Dorset; long after walrus hunting had become less productive.

The Pre-Dorset culture is characterized by small ephemeral dwellings, high mobility, and a heavy reliance on ringed seal at the coast and caribou inland. Around 500BC, environmental changes produced an ideal habitat for walrus, particularly in Foxe Basin, the area of this study. This stable and abundant food source brought about changes leading to the Dorset culture, including larger and more permanent settlements, and increased storage. Walruses are large and dangerous marine mammals, and as such, walrus hunting is similar to whaling, which occurs in organized, hierarchical groups. Murray argues that the new form of harpoon heads show unique markings to claim ownership over the killed walruses because killing one of these large and dangerous animals was associated with prestige for the hunter.

On a larger scale, this increase in resource availability in the Foxe Basin promoted a more sedentary lifestyle involving longhouses, storage caches, and intensified walrus hunting. According to Binfod’s 1980 classification scheme, the Dorset culture experienced a shift from a residential mobility pattern to logistical organization. As groups became more associated with specific places on the landscape, group identity became more focused on the location and transcended the individual social relations, taking on a permanence that was not dependant on a particular individual or individuals.

Also, the increase in walrus availability was not uniform throughout the region inhabited by the Dorset culture, with the greatest abundance occurring in the Foxe Basin. This led to an accumulation of wealth and prestige by the Foxe Basin groups, a hierarchical trading structure, and more formalized inter-group relations.

Eventually, over-exploitation led to a decrease in walrus availability and the focus of hunting returned to the ringed seal, marking the transition to the Late-Dorset. However, the prestige relationships created in the Dorset culture were self-perpetuating and the traditions associated with this prestige, such as longhouses, continued beyond the time that they would have been beneficial to the Paleoeskimo people. Murray concludes that this short-term and localized abundance had long-lasting effects on the Dorset and Late-Dorset cultural identities.

This study of the socio-economic change associated with a changing resource base gives an interesting look at the cultural forces that would have been at play, an element that is often lacking in discussions of environmental and subsistence shifts. If this explanation of the social dynamics of is correct, it will provide another example against the strictly egalitarian nature of hunter-gatherer groups, and an example of how the accumulation of wealth can begin. However, Murray provides little concrete evidence for her conclusions about how this played out in the social and cultural spheres, instead referring the reader to works by other archaeologists.

What she does not discuss are the changes in subsistence other than the decrease in reliance on ringed seal and intensification of walrus hunting (refer to figure 4 of Murray 1999). There appears to be a general broadening of resources exploited, with ringed seal remains decreasing from almost 90% to about 15% of the faunal assemblage, and the exploitation of arctic fox, bearded seal, caribou, walrus, fish and birds showing an increase. In particular, the most common remains found in the Dorset culture are those of arctic fox, which increases from nearly 0% to about 35%, a greater increase than is seen in walrus remains. Although walrus is much larger than fox, and would have provided a greater portion of the diet even if less frequently hunted, there appear to be other important trends that Murray does not mention and may have been as significant in the socio-economic prestige systems.

References

Binford, Lewis R.

1980. Willow Smoke and Dogs' Tails: Hunter-Gatherer Settlement Systems and

Archaeological Site Formation. American Antiquity. 45(1): 4-20.

Murray, Maribeth S.

1999. Local heroes. The long-term effects of short-term prosperity – an example from the Canadian Arctic. World Archaeology. 30(3): 466-483.