Category Archives: hunter-gatherer economy

"Modern human behavior" is out, generic human potential is in

There is a hypothetical model in Prehistory on something vague and ethereal which has been called “Modern human behavior” (MHB). It’s not about nuclear weapons, Internet addiction nor commuting to work; it’s not either about the printing machine, the Industrial Revolution and the ideals of Human Rights; it’s not even about farming, living in cities and through sailing the seas… it’s about something extremely vague and ill-defined but which, by definition would set apart “modern humans” (H. sapiens) from “archaic humans” (other Homo species, particularly Neanderthals).
While it is almost intangible and every day more dubious, a large number of prehistorians, some as notorious as Mellars, Stringer or Bar-Yosef, strikingly influenced by religious ideas setting an arbitrarily absolutist line between “humans” (i.e. Homo sapiens) and the rest (including other humans), have insisted for decades on the validity of such notion. Now three researchers challenge the model radically:
Christopher J. H. James, Julien Riel-Salvatore & Benjamin R. Collins, Why We Need an Alternative Approach to the Study of Modern Human Behaviour. Canadian Journal of Archaeology Volume 37, Issue 1 (2013). Pay per viewLINK


In this paper we review recent developments in the debate over the emergence of modern human behaviour (MHB) to show that despite considerable diversity among competing models, the identification of given material traits still underpins almost all current perspectives. This approach, however, allows assumptions over the biological relationship between archaic and modern humans to permeate the definitions of MHB and, as a result, has effectively stultified archaeology’s potential contribution to the issue. We suggest that the concept of MHB as currently defined is flawed. It must either be redefined in strictly behavioural terms before reincorporation into the debate over modern human origins or, more productively, discarded all together to avoid the harsh and unrealistic dichotomy it creates between a modern and non-modern archaeological record.
They essentially argue that: that the model (of which there are several, often contradictory variants) is extremely useless and confusing, that there are “archaic humans” with many or even all traits of MHB and there are “modern humans” without many or even most of them.
They tentatively argue for a throughout revision of the model but then they seem to lean rather for the whole abandonment of the idea suggesting instead a mosaic and punctuated evolution pattern that is socio-cultural rather than merely genetic or essentialist:

(…) the rapidly accumulating evidence for a mosaic pattern of behavioural change (…) and the evidence of behavioural advances appearing and rapidly disappearing in the MSA, make the harsh dichotomy model untenable. What it does suggest is a punctuated or saltation model that led to widespread adoption of more complex behavioural patterns once the demographic circumstances were appropriate (…).

Somehow this made me recall one of my all-time favorite bands: Suicidal Tendencies and their 1990 hit “Disco’s out, murder’s in” (surely not apt for pop, techno and folk music lovers):

Mouth bacteria changed with civilization… for worse

A premise of Primitivism, which is not really a doctrine or philosophy but more like realistic approach to the human condition, is that our evolutionary past is shaped almost totally by hunter-gathering. That we are basically hunter-gatherers in a jump or maybe formal suit. Why? Because some 95% of the biological history of Homo sapiens, as a formed species is one of hunter-gathering, not of productive economy nor civilization. This percentage can be extended to maybe 99.5% if we consider the whole history of the genus homo, etc. And that is a lot. 
Do I digress? Well, maybe not so much after all. The evolutionary news today is in any case that the bacterial ecosystems in our mouths have been degenerating since Neolithic, and then again with Industrialization. As Not exactly rocket science (a National Geographic blog written by Ed Yong) explains the bacteria in our mouth is not all hostile but, at least for hunter-gatherers, often balanced: some bacteria may attack our teeth but then others protect and even repair them. Much like the better known bacteria of our guts, there is a general balance in which, naturally at least, symbiosis with the human needs tends to dominate. After all those bacteria live in our mouths and therefore need it to exist in good shape: they may not be exactly “aware” of their own needs or the benefits of harm they bring to us but evolution fixes it in the long run, of course. 
Epipaleolithic foragers from Poland with a rather thick plaque, plaque that retained in millennial hibernation the bacteria of their mouth, have provided evidence of Prehistoric hunter-gatherers having a healthy, balanced mouth bacterial ecology. 
Instead Medieval English, who were already eating many carbohydrates from cereals, illustrate with their plaque the beginning of mouth bacterial decadence. There are a total of 34 studied remains between these two dates, illustrating that this change happened exactly with the Neolithic Revolution.
The members of the modern research team used their own mouths as reference for the modern bacterial environment. The results were rather depressing: industrialization has created many refined, unbalanced, foods (white cereals and sugar especially) that cause our mouths to be the boon of dentists.
We are what we eat

A similar kind of bacterial ecology decadence was observed in a previous study between the guts of Burkinabe farmers’ children and those of Italian urban ones. The latter have ecosystems dominated by well-fed firmicutes, associated to obesity.

Reference paper:  Christina J. Adler et al., Sequencing ancient calcified dental plaque shows changes in oral microbiota with dietary shifts of the Neolithic and Industrial revolutions. Nature 2013. Pay per viewLINK [doi:10.1038/ng.2536]


Early farming was inefficient compared to foraging

Early farming was only able to generate some 60% of what foraging (hunting and gathering) did, according to new research:
Samuel Bowles, Cultivation of cereals by the first farmers was not more productive than foraging. PNAS, 2011. Pay per view (depending on world region and time).


Did foragers become farmers because cultivation of crops was simply a better way to make a living? If so, what is arguably the greatest ever revolution in human livelihoods is readily explained. To answer the question, I estimate the caloric returns per hour of labor devoted to foraging wild species and cultivating the cereals exploited by the first farmers, using data on foragers and land-abundant hand-tool farmers in the ethnographic and historical record, as well as archaeological evidence. A convincing answer must account not only for the work of foraging and cultivation but also for storage, processing, and other indirect labor, and for the costs associated with the delayed nature of agricultural production and the greater exposure to risk of those whose livelihoods depended on a few cultivars rather than a larger number of wild species. Notwithstanding the considerable uncertainty to which these estimates inevitably are subject, the evidence is inconsistent with the hypothesis that the productivity of the first farmers exceeded that of early Holocene foragers. Social and demographic aspects of farming, rather than its productivity, may have been essential to its emergence and spread. Prominent among these aspects may have been the contribution of farming to population growth and to military prowess, both promoting the spread of farming as a livelihood.
A news article is also available at PhysOrg.
Is the alternative explanation correct?
I find this discovery most interesting because the assumption has generally been that automatically farming was more productive than the old human way of life: foraging what Nature had to offer. 
Yet this assumption did not explain why farming had not evolved earlier or why the, generally very pragmatic, peoples of the World, did not adopt it earlier, as they were no doubt aware of how gardening could be done.
It reminds me somewhat of the very much comparable misunderstanding on the transition from the Bronze to the Iron Age: iron had by then been known for very long but it was brittle in comparison with bronze, quasi-bronze (copper and arsenicum) and even the old good flint stone. Actually I read somewhere recently that another good old friend of humankind, obsidian, makes such great blades that compete favorably with steel scalpels.
Things are not so simple: steel began to be developed (as sweet iron is not really good for most uses) after tin resources began to fail in the Eastern Mediterranean, as the communications with Atlantic Europe (where most tin mines were back then) may have collapsed when the two classical Iberian civilizations, El Argar and Zambujal (VNSP), did as well for reasons not well understood and not too relevant to discuss here. 
It was therefore problems in the bronze industry, so critical for the military of the time, what pushed steel technology ahead, inaugurating the Iron Age.
Molino neolítico de vaivén
Seed milling was done long before Neolithic too
Therefore I’d like to consider what may have caused people to adopt farming instead of just continue foraging, as they had done successfully until that time. We know that farming was preceded by a period we call Mesolithic and that is characterized by intensive foraging of wild cereals or other foraging behaviors that somehow announce the advent of farming or herding. 
So, in the Fertile Crescent, there was for a time, since about the end of the Ice Age, a focus on a pre-farming type of foraging. As I have not read the paper yet, I do not know if Bowles has factored this period in his equations. As for me, I’d think that this kind of foraging (maybe already associated to some early gardening practices) we call Mesolithic, seems to respond to an ecological pressure of some sort, no doubt related to the then ongoing climate change. 
Another issue I am pondering is that, even before cereal farming was fully developed in Palestine, herding of sheep and goat was adopted in Kurdistan, followed by cow herding in Anatolia (near the well-named Taurus mountains). Maybe herding had to be developed in order to make farming effective? Cattle (be it bovine or ovi-caprine) provides nutrients in form of manure and, goats specially but not only, can also be used to clear up wild vegetation areas, while pigs are great to plow the fields.
So I am wondering if animal domestication was a condition to make cereal (and pulse and flax) farming an economically effective way of life. 
Honestly I prefer a true economic explanation rather than one based on very conjectural preferences about sedentarism, and this may be made up of:
  • The push factor of climate change at the end of the Ice Age
  • The pull factor of animal domestication, increasing the yields of agriculture until it became economically worthwile
What do you think?

Human natural societies flexible and not primarily built on genetic kinship

Understanding hunter-gatherer societies is important because we are after all just paleolithic peoples dumped into Market Street. Our flexibility allows us to deal with this strange unnatural reality with some ease but this is not the context in which we evolved, not at all.
New research in this ancestral reality of us, embodied in a variety of surviving hunter-gatherer groups, provides some interesting results:


Contemporary humans exhibit spectacular biological success derived from cumulative culture and cooperation. The origins of these traits may be related to our ancestral group structure. Because humans lived as foragers for 95% of our species’ history, we analyzed co-residence patterns among 32 present-day foraging societies (total n = 5067 individuals, mean experienced band size = 28.2 adults). We found that hunter-gatherers display a unique social structure where (i) either sex may disperse or remain in their natal group, (ii) adult brothers and sisters often co-reside, and (iii) most individuals in residential groups are genetically unrelated. These patterns produce large interaction networks of unrelated adults and suggest that inclusive fitness cannot explain extensive cooperation in hunter-gatherer bands. However, large social networks may help to explain why humans evolved capacities for social learning that resulted in cumulative culture. 
A news article is also available at Science Daily.
What may seem a bit unexpected is how this social structure is not at all like any related primate group. Our closest relatives live in individual units (orangutans), in single-male dominated harems (gorillas), in patrilocal promiscuous communities (chimpanzees) and in matrilocal even more promiscuous ones (bonobos). 
Instead humans form bands, typically of some 28 individuals, which are neither patrilocal nor matrilocal, and end up including people who are mostly not even closely related to each other. There it goes genetic egoism down the toilet!
This structure actually seems to integrate wider networks of relationships beyond the band, which (from other sources) is typically so flexible that it loses and gains members very frequently. Probably what this implies is ethnic (tribal) networks as main unit, however not even these are closed to strangers, not at all.
The research included some 5000 people from the following nations: Gunwinggu (Australia), Labrador Inuit, Apache, Ache (America), Mbuti, Aka (Africa), Agta and Vedda (Asia).

Update (Mar 17): Blackbird, who runs some interesting blogs on non-human animals you may want to check, mentions that our Pan sp. cousins, both chimpanzees and bonobos, may not be as gender biased as we used to think in regards on who moves and who lives in the established community. The following paper addresses this matter a bit and also includes an interesting analysis of haploid genetics among bonobos (all of which live in D.R. Congo):

Jonas Erikson et al, Y-chromosome analysis confirms highly sex-biased dispersal and suggests a low male effective population size in bonobos (Pan paniscus). Molecular Ecology 2006. [doi: 10.1111/j.1365-294X.2006.02845.x]

He (Blackbird) suggests, and he may be right I’d say, that this ambiguity of locality is similar to what Hills observes for Homo sapiens and may therefore be a shared pattern among the super-genus.  


Modeling cultural diversity, local extinctions, etc.

Before I forget, just a quick mention of another potentially interesting paper published at PLoS ONE this week:

L.S. Premo and S.L. Kuhn, Modeling Effects of Local Extinctions on Culture Change and Diversity in the Paleolithic. PLoS ONE 2010. Open access.

The persistence of early stone tool technologies has puzzled archaeologists for decades. Cognitively based explanations, which presume either lack of ability to innovate or extreme conformism, do not account for the totality of the empirical patterns. Following recent research, this study explores the effects of demographic factors on rates of culture change and diversification. We investigate whether the appearance of stability in early Paleolithic technologies could result from frequent extinctions of local subpopulations within a persistent metapopulation. A spatially explicit agent-based model was constructed to test the influence of local extinction rate on three general cultural patterns that archaeologists might observe in the material record: total diversity, differentiation among spatially defined groups, and the rate of cumulative change. The model shows that diversity, differentiation, and the rate of cumulative cultural change would be strongly affected by local extinction rates, in some cases mimicking the results of conformist cultural transmission. The results have implications for understanding spatial and temporal patterning in ancient material culture.

This mention is not adhesion. I find the modeling potentially interesting in its essentials but I surely have many discrepancies on issues such as assuming tiny “populations” of some 25 individuals in black and white (life or death) states. Such size is ok with operative hunter-gatherer bands but these are not “sovereign” units but just dynamic and fluctuating economic ones, integrated in larger groups. Probably a better size would be something like 100 or 200 people but again integrated into larger units of several hundreds to several thousands (tribes or nations).

Also we have to consider that people change “clans”, for example when marrying. So cultural, as well genetic flow is persistent at least within the borders of the ethnicity, which are anyhow generally open. So I guess that the modeling needs a lot of refinement but still it is a curious speculation – or exploration if you wish.

Something I do agree is in the authors founding their research on previous works that strongly suggest that population size and specially connectivity is critical in driving and maintaining the rhythm of innovation.