Saturday, August 9, 2014

The agricultural revolution that wasn't


 

 
Originally from south China, Austronesians spread successively outward to Taiwan, Southeast Asia, and Oceania. Was farming the secret of their success? Or was it their mental makeup? (source: French Wikipedia - Maulucioni)

 

About 10,000 years ago, the pace of human genetic evolution rose a hundred-fold (Hawks et al., 2007). Our ancestors were no longer adapting to slowly changing physical environments. They were adapting to rapidly evolving cultural environments.

What, exactly, caused this speed-up? The usual answer is the shift from hunting and gathering to farming, which in turn caused other changes. People were becoming sedentary and living in ever larger communities: villages, towns, and finally cities. Farming also produced a food surplus to be stored for future use, thereby providing powerful men with the means to bankroll a growing number of servants, soldiers, and other hangers-on. Thus began the formation of early states. And thus ended the primitive equality of hunter-gatherers.

But is that the whole story? Was farming the trigger for this chain of events? Or did something earlier get things going? More and more anthropologists are taking a closer look at what happened just before the advent of farming, a period called the "Broad Spectrum Revolution": 

All Paleolithic hominids lived by hunting and collecting wild foods, an aspect of existence that began to disappear only with the emergence of the farming and herding societies of the Neolithic ≤10,000 years ago (10 KYA). What are the roots of this remarkable economic transformation? The answer lies in equally revolutionary changes that took place within certain stone age cultures several millennia before. In 1968, Lewis R. Binford noted what appeared to be substantial diversification of human diets in middle- and high-latitude Europe at the end of the Paleolithic, roughly 12-8 KYA. Rapid diversification in hunting, food processing, and food storage equipment generally accompanied dietary shifts, symptoms of intensified use of habitats, and fuller exploitation of the potential foodstuffs they contained. (Stiner, 2001).

Farming thus came on the heels of a broader cultural, behavioral, and even psychological revolution. It is this broader change, rather than farming alone, that probably caused many supposedly farming-related events, such as the rapid spread of certain agricultural peoples into territories that formerly belonged to hunter-gatherers. Examples include the Bantu expansion, which began about 4,000 years ago along the Nigerian/Cameroun border and spread east and south, eventually throughout almost all of central, eastern and southern Africa. There was also the more controversial Neolithic expansion, which started about 10,000 years ago in present-day Turkey and pushed north and west into Europe. Finally, there was the Austronesian expansion, which began over 6,000 years ago when Malay-speaking farmers crossed from south China to Taiwan. Then, some 4,000 years ago, they began to push rapidly into Southeast Asia and Oceania, finally reaching places as far apart as Easter Island and Madagascar.

Farming is said to have fueled all three demographic expansions. It created more food, which in turn created more people, who then bulldozed the less numerous hunter-gatherers out of existence. Yet this theoretical model does not fit the Austronesian expansion very well, as anthropologist Roger Blench points out:

The [existing] model proposes that it was the Austronesian adoption of an agricultural package, including rice, pigs and chickens, which allowed them to colonise Island SE Asia at the expense of resident hunter-gatherers. However, archaeology has signally failed to confirm this model. Early sites show very similar dates across a wide geographical area, suggesting that the first phase of post-Taiwan Austronesian expansion took place extremely rapidly. Pigs, dogs and chickens have been shown to arrive in ISEA via other routes and rice is conspicuously absent in most places. This paper argues that this model has effectively inverted the actual situation, and that the Austronesian expansion was the consequence of a failed agricultural revolution and a reversion to opportunistic foraging. (Blench, 2014)

There was no "package" of domesticated plants and animals that enabled Austronesians to overwhelm the earlier inhabitants of Southeast Asia:

No remains of cereals of the relevant antiquity have been found in the Northern Philippines. Even today, the characteristic millets of the Asian mainland are barely represented in ISEA agriculture. Of the dogs, pigs and chickens originally thought to be part of the Austronesian 'package' only pigs cross the Taiwan Strait, and these now seem to be a local domestication not ancestral to the domestic pigs which are generally part of the Austronesian world. The apparent reconstructions for names of these domestic species formed part of the argument for their salience, but as Blench (2012) points out, these were based on chains of loanwords giving an appearance of spurious antiquity. (Blench, 2014)

Not only did the Austronesians bring a limited farming package to Southeast Asia, the existing peoples there already practiced a mix of farming and foraging:

Ellen (1988) describes this type of mixed vegeculture and arboriculture, a sedentary lifestyle based around sago extraction, for Seram in Eastern Indonesia. Stark (1996) touches on this hypothesis in a discussion of the archaeology of Eastern Indonesia, and Kyle Latinis (2000) discusses the broader role of arboriculture in early subsistence in ISEA. Hunt & Rushworth (2005) report evidence for disturbance in the tropical lowland forest at Niah, Sarawak, Malaysian Borneo at 6000 BP which they attribute to cultivation. Huw Barton (2012) has evidence from starch on stone pounders in the Kelabit highlands for palm granules earlier than 6500 BP. (Blench, 2014)

The incoming Austronesians really brought little, agriculturally speaking. In some cases, they actually reverted to foraging. In other cases, they adopted various crops and farm animals from the locals.

The picture is diverse, suggesting continued foraging, vegeculture, and sago starch extraction. Hence the concept that the maritime Austronesians reverted to a type of subsistence based on fishing, trading, possibly raiding and exchange of prestige goods. With their advanced sailing technology, they were well-placed to carry high-value goods from one exchange site to another. Their encounter with the Melanesian populations in Eastern Indonesia is certainly responsible for their adoption of vegeculture and domestic animals, but they were willing to drop and re-adopt these according to the circumstances of individual cultures they encountered. (Blench, 2014)

The Austronesians are often treated in the existing literature as a type-society for demographic expansion, with agriculture the underlying engine of growth. This is in increasing disaccord with the archaeology of the region, and this paper will suggest that the explanation is almost its inverse, that they succeeded precisely because they strategically reverted to foraging. (Blench, 2014)

What advantage, then, did the Austronesians have over the natives they displaced? There must have been something to offset the "home team" advantage of the natives, who knew the local environment better than anyone else. 

The Austronesian advantage seems to have been threefold: (1) a more flexible and innovative approach; (2) a less present-oriented time orientation that extended further into the past and the future; and (3) a less individualistic approach to life that made collective goods and goals more possible.
 

Flexibility and innovation

Blench (2014) states: “Austronesians quickly reinvented themselves, incorporating regional innovations into their cultural repertoire. Apart from their own distinctive pottery, they must have quickly seized on other early trade possibilities, obsidian, stone axes, woven goods and baskets. By the time they begin to reach uninhabited islands they have constructed Austronesian culture out of fragmentary elements adopted from a wide range of sources.”
 

Time orientation

The Austronesians saw themselves as the embodiment of lineages that stretched backwards into the past and forwards into the future. Preservation of genealogies seems to have been a typical cultural trait of Austronesian peoples, and this ancestor worship fostered a widespread desire among them to become revered ancestors. Quoting an earlier author, Blench (2014) points to "a culturally sanctioned desire to found new settlements in order to become a revered or even deified founder ancestor in the genealogies of future generations." The rapidity of the Austronesian expansion was thus, in part, ideologically driven.
 

Collectivism

Blench (2014) refers to "the striking differences between Austronesians in contact with Melanesians, whose typical social structures were individualist, acephalous and marked by great diversity in approaches to religion and belief." Austronesian society was more hierarchical with caste-like elements, particularly priestly castes who acted as repositories of esoteric knowledge. Belief-systems were more homogeneous. Austronesian peoples have long shown evidence of strong religiosity, even those who have not converted to Hinduism, Islam, or Catholicism.
 

Conclusion

One of my professors, Bernard Arcand, would talk to us about the hunter-gatherers of Upper Amazonia and their indifference to farming. They saw it as something akin to slavery and couldn't understand why anyone would want to stay put in one place and toil in the fields all day. Attempts to teach them the benefits of farming typically failed. Benefits? What benefits?

There has to be a change in mental makeup before farming becomes possible. People must become willing to exchange short-term pain for long-term gain. They must accept monotony and sedentary living. They must live in larger communities with people who are not necessarily close kin. And they must get used to bland, nutrient-poor food.

Anthropology has long tried to explain human societies in terms of their modes of subsistence: hunting and gathering, farming, industrial capitalism. This material basis of society is thus the source of our mental makeup. In reality, the two have coevolved with each other. Moreover, when humans adapt to a certain mode of subsistence, they may become "pre-adapted" to later ones. We associate the dawn of civilization with a shift toward future time orientation and a resulting complexification of technology, yet this shift seems to have first begun among hunter-gatherers of the sub-Arctic, where the yearly cycle required development of technologies for storage, meat refrigeration, and heat conservation, as well as other means to collect unpredictable and widely dispersed resources. This 'first industrial revolution' pre-adapted early modern humans for later cultural developments in places farther south. 

It is perhaps no coincidence that most of the human gene pool ultimately came from people who, more than 10,000 years ago, roamed the northern wastes of Eurasia. Such people were ancestral to many southward-pushing demographic expansions, including the one that would give rise to the Austronesians (Frost, 2014).

 

References

Blench, R. (2014). The Austronesians: An agricultural revolution that failed, To be presented at the Second International Conference on Taiwan Indigenous Peoples, 15-17 September 2014 Shung Ye Museum, Taipei, Taiwan
http://rb.rowbory.co.uk/Archaeology/Oceania/Blench%20Austronesian%20Taipei%202014%20agric%20failed.pdf

Cochran, G. and H. Harpending. (2009). The 10,000 Year Explosion: How Civilizations Accelerated Human Evolution, Basic Books, New York. 

Frost, P. (2014). The first industrial revolution, Evo and Proud, January 18
http://evoandproud.blogspot.ca/2014/01/the-first-industrial-revolution.html  

Hawks, J., E.T. Wang, G.M. Cochran, H.C. Harpending, & R.K. Moyzis. (2007). Recent acceleration of human adaptive evolution. Proceedings of the National Academy of Sciences (USA), 104, 20753-20758.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2410101/  

Stiner, M.C. (2001). Thirty years on the "Broad Spectrum Revolution" and paleolithic demography, Proceedings of the National Academy of Sciences, 98 (13), 6993-6996.
http://hatayup.web.arizona.edu/pubs/stiner2001.pdf

12 comments:

Anonymous said...

Two questions:

First, what does the genetic data say about admixture between Austronesian and Papuan/Melanesian peoples over the range of Austronesian dispersal? How much do, say, Tahitians differ from, say, Filipinos or Javanese in this regard?

Second, what's the score on average IQ in Austronesian versus Melanesian populations? I seem to recall from Piffer's study earlier this year that Melanesian groups had an average of 25 percent incidence of the gene variants he surveyed - lower than Eurasians but higher than sub-Saharan African. But I don't remember what the Indonesian/Micronesian/Polynesian figures were, if indeed they were included.

Juoni said...

If longer future-orientation (=higher intelligence) is a crusial part of becoming farmers, then what was the selection pressure in the case of Bantu-people?

Not climate for sure.

Beyond Anon said...

This pattern of rapid dispersals
followed by pauses strongly resembles the ‘punctuated equilibrium’ model of evolution delineated by Niles Eldredge and Stephen J. Gould (1972).


Heh. Not sure they would appreciate the reference.

pyrrhus said...

Very fine piece, Peter. It sounds to me like these Austronesians developed some very flexible, opportunity seeking minds. Could we call that quality something like "g"?

Jim said...

Peter - I had thought the expansion into Oceania began about 3,000 years ago I recall reading that archaeological evidence in Guam indicates human presence there since about 1000 BC and this is among the earliest known occupied sites. Is there new evidence for earlier presence of humans in Oceania?

By the term "Oceania" I am excluding New Guinea and nearby islands such as the Solomon's etc. where archaeological evidence of human presence goes back at least 30,000 years.

Peter Fros_ said...

Anon,

The best map of Papuan admixture appears in:

Shuhua Xu, Irina Pugach, Mark Stoneking, Manfred Kayser, Li Jin, and The HUGO Pan-Asian SNP Consortium. (2012). Genetic dating indicates that the Asian–Papuan admixture through Eastern Indonesia corresponds to the Austronesian expansion. PNAS
http://www.pnas.org/content/early/2012/03/05/1118892109.abstract

I haven't seen any good IQ data for Austronesian or Melanesian populations. Piffer's study did not include any Austronesian populations.

Juoni,

Farming doesn't require as much future time orientation in the tropics as it does outside the tropics. The Bantu expansion may or may not have been driven solely by farming. This is a question that should be re-examined because many anthropologists have assumed that farming is the sole explanation for all of these expansions.

Beyond Anon,

Dead men don't mind being cited.

Pyrrhus,

I don't deny the existence of the g factor, but I don't think it is the only mental trait worth studying.

Jim,

Yes, relatively recent evidence has pushed these dates farther back in time. See Reid (2002) and Hung et al. (2011) in Blench's references.

JIm said...

Peter - Thanks for the references you provided. I lived in Guam when I was a child and I have a special interest in Oceania.

BenK said...

Adaptationist arguments that require a spatially local fitness advantage are not necessary to explain the displacement of local Micronesian populations by the Austronesians.

All it requires is an already well-established migration pressure. With superior ships, the incoming group would have been able to relatively quickly populate any sites that experienced temporary demographic setbacks - perturbations, disturbances. Famine, war, disease, whatever it was, if the new group could find and utilize the site,... well, there was no competition on the relevant time scale at the smaller spatial scale.

Jim said...

BenK - What is the evidence for populations in the Micronesians who did not speak Austronesian languages? I believe that the archaeological evidence in Guam dating from 1000 BC. indicates probable migration from the Phillipines and continuity since then. Chamorro is an Austronesian language.

The funny thing about the archaeological evidence from the Micronesians is that except for the Marianas the earliest dated sites are in the East and some of the youngest in Yap and Palau. So it looks like a migration from East to West but this may be an artifact of just which sites have been discovered so far.

Peter Fros_ said...

Ben,

That's the traditional model, i.e., a steady demographic expansion driven by more numerous farmers at the expense of less numerous hunter-gatherers.

Blench argues, convincingly in my view, that this model is inadequate. The Austronesian expansion involved very rapid dispersals, often within a time range of a few hundred years.

BenK said...

Peter, Jim;
Thank you, I'm not an expert at this at all. I'm just suggesting that there needn't be any advantage besides the ability to move/migrate - i.e. the boats - if populations fluctuate rather severely for one or both types of people. In fact, local fitnesses could be the inverse.

roelm said...

Blench presents a plausible scenario with regards to the mind-set of the Austronesians. I also find very interesting the contention that Daic is an offshoot or at least very closely related to Proto-Malayo-Polynesian. He may be overstating it somewhat when he says "an agricultural revolution that failed", however. Here is a quotation from a Bellwood paper:
http://www.jstor.org/stable/10.1086/658181

"Comparative lexical reconstructions for PAn and its daughters PMP and proto-Oceanic (POc) indicate major changes in material culture through time and space (Blust 2009; Pawley 2002; Ross, Pawley, and Osmond 2007). For PAn itself, they reveal an economy focused on rice cultivation, with a large vocabulary for rice in many forms and stages of growth as well as a processing and cultivating vocabulary with words for millet, sugarcane, and possibly aroids. PMP added many fruits and tubers to this vocabulary as befitted its probable location in the tropical Philippines (Taiwan is mostly temperate in latitude). POc witnessed the ultimate loss of rice under equatorial climatic and day-length conditions (Paz 2002:280). Other reconstructions apply to words for pigs and dogs (but not chickens until PMP), pottery, boats and sails, fishing, and a wild placental (not marsupial) mammal fauna. The morphological and semantic integrity of these many reconstructions, as Pawley (2002:266) points out, implies continuous linguistic transmission through time, not late borrowing. In other words, Austronesians did not start as farmers, revert to foraging and lose all their farming vocabulary, and then readopt farming much later. Even the few centuries of naive faunal exploitation on Remote Oceanic islands did not reduce the food-producing vocabulary of Polynesians. Furthermore, the rakelike phylogeny of the main MP subgroups implies rapid migrational spread at least from the Philippines to as far east as western Polynesia (Gray, Drummond, and Greenhill 2009; Pawley 1999)."

Note also the section in the paper entitled "How Significant Were Rice and Pigs?".