Jared Diamond Guns, Germs and Steel, 1997, Hardback Feature

What is History 10: Polynesia a Natural Experiment of History

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What is History 10: Polynesia a Natural Experiment of History — Guns, Germs & Steel by Jared Diamond

Articles in the What is History? series are 1 Introduction 2 Sleep Patterns, 3 The Medieval Mind, 4 Love,  5  EH Carr Historians & their facts, 6  Religion 7 EH Carr Causation in History, 8 EH Carr History as Progress , 9 Guns, Germs & Steel Overview and 11 World Economic History.

I introduced Jared Diamond and Guns, Germs & Steel in my introductory article on What is History? and again in article 9 with an overview. Diamond is a biologist as I am by training. His foray into history is almost one of frustration. Because as a biologist he understands evolution and is interested how an intelligent naked ape might develop into what we recognise as a human being (Homo sapiens) and how humans might develop agriculture, settled towns, city states, political structures and civilisations.

Yuval Harari (a historian) in Sapiens is attempting something similar from a different perspective.

The development of human history is set in a background of geography, climate, the distribution of plants and animals and other external factors. These sorts of things are quite acceptable as the study of ecology with animals and plants, but suddenly become less acceptable when one deals with human beings and human history.

Diamond’s frustration with history was because mainstream history did not cover the issues of the biological origin of human beings, the development from a hunter gathering background and the influence of such things that can loosely be called environment on human history.

Diamond is frequently labelled as an environmental determinist and dismissed, but that is wilfully misunderstanding what he is trying to do. Part of this is simply an unwillingness to accept a different approach, but Diamond is also at fault for the quirky way he approached his topic.

In article 9, I felt the need to give an overview to the good, the bad and the controversial in Guns, Germs and Steel to get over these issues so that we could begin to look at some of the important findings contained in the book and their implications for human history.

A unique idea

Of a normal book, if I said that Diamond’s one original idea was… I would be readying myself to belittle the work.

However, we are talking about a generalist work in Guns, Germs and Steel whose aim is to examine the impact of external forces, especially of a biogeographical kind, on human history. Generalist integrating works are moderately unusual because they require synthesis of a diverse array of disparate academic disciplines and they rarely contain new ideas other than the generalist overview itself.

In spite of this, there is one very original idea in Guns, Germs and Steel, that Diamond appears to have had, which he outlines in Chapter 2 A Natural Experiment of History.

It is Diamond’s apparently novel idea that is the basis for the remainder of this article.

With humans, one can’t take a group of subjects and expose them to some form of experimentation over generations to prove or disprove some hypothesis. (That has only happened in Douglas Adams The Hitchhikers Guide to the Galaxy.) One can do this in biological science. For example, one could imagine placing experimental populations of wild rats in enclosed colonies and subjecting them to different controlled environmental conditions over generations.

In human history one can make some assertions such as, the development of agriculture occurred in various places because of local scarcity of resources, or droughts on the Mongolian steppes propelled tribes of warrior horsemen towards China or Europe. But, one cannot experimentally verify such assertions. Or, easily state whether they are true or false.

Diamond because of his biological background would have liked to experimentally verify aspects of human history but could not. However, because of his long association with New Guinea and his knowledge of the Pacific, he eventually came to the idea that the Polynesian expansion into the Pacific provided the most known and perhaps the only verifiable natural experiment of history in the history of humankind.

Unfortunately, the apparent novelty of the idea is not Diamond’s. Patrick Vinton Kirch, Diamond’s main source of information on Polynesia, said in a personnel communication that he and others had raised the idea in the scholarly literature several times and that it was well-known amongst researchers in the Pacific (see Further Information).

Similarly, on the biological side, Jared Diamond would have been aware of and influenced by The Theory of Island Biogeography by Robert MacArthur and Edward O Wilson 1967. Kirch and McNeill (pers. comm.) and virtually all other field biologists of this generation were also well-aware of the book. Kirch says it had a huge influence in his formative years and that he still consults it on occasion. It is very difficult in science to have an original idea.

The Theory of Island Biogeography was a hugely influential book based in part on EO Wilson’s studies of the ants of Melanesia. The purpose was to attempt to take the development of ecology from a natural history setting towards that of a predictive science. Subsequent to the book EO Wilson and a graduate student Daniel Simberloff fumigated six small mangrove islands in the Florida Keys to clear them of arthropods and then studied the recolonisation. They confirmed one prediction from The Theory of Island Biogeography that there was an inverse relationship between the number of species on each island and the distance from the source region.

This was heady theoretical and experimental stuff in the heyday of ecology in the 1960s and 1970s. And, the ideas are similar in essence to the Polynesian expansion into the Pacific being such an experiment of natural history.

Background on the Austronesian people

Although it seems to be in reverse, Chapter 17 Speedboat to Polynesia: the history of the Austronesian Expansion in Guns, Germs and Steel sets the scene for the wonderfully original idea in Chapter 2.

Diamond uses the evidence of linguistics and archaeology developed by others to espouse the mainstream ‘out of Taiwan model’.

Austronesian-speaking people made a seaborne expansion out of Taiwan about 3500 BCE. In three paths they populated South East Asia, travelled west to Madagascar and east into Micronesia and Melanesia.

Around 1600 BCE to 500 BCE Lapita people defined by specific red-slipped pottery were expert seafarers and navigators. The Lapita are thought to be ancestors of historic cultures in Micronesia, Polynesia and coastal areas of Melanesia. The main Lapita archeological sites with characteristic pottery are found in Melanesia and into Polynesia (Samoa, Fiji, Tonga, New Caledonia).

Their descendents, the Polynesians went on to populate islands east across the Pacific, ranging from New Zealand to Hawaii, Tahiti and Easter Island. Pottery persisted in Fiji but disappeared completely from other areas of Melanesia and from Polynesian culture.

This story of pre-historic Austronesian expansion is relatively uncontroversial. Although, the dates and details are subject to debate.

Similarly, Diamond’s dates on historic Polynesian expansion have also changed slightly over the years. For example, where he puts Maori arrival in New Zealand at 1000 AD, current estimates are 800 years ago (but even this is open to debate).

Polynesian Expansion a Natural Experiment of History

Polynesia is defined roughly as a triangle from New Zealand to Hawaii to Easter Island (Rapa Nui). Fiji, Vanuatu, Kirabati and the Marshall Islands are not in Polynesia. The first two are in Melanesia and the last two in Micronesia (but the fine distinctions are relatively arbitrary).

Using Diamond’s timeline for Polynesia, Tonga and New Caledonia were settled around 1200 BCE, the Society and Cook Islands around 1 AD, Hawaii and Easter Island around 500 AD and New Zealand about 1000 AD and the Chatham Islands about 1300 AD.

The key element of the Polynesian expansion was that it occurred in historic times. The Polynesians had a common language and culture that remains stable and identifiable today. Each group started with basically the same package of animals, plants and technology with slight exceptions. In each society eating animals was occasional. Mostly they were dependent on their agricultural plants and of course fish.

John McNeill in Of Rats and Men 1994 uses the term ‘portmanteau biota’ taken from Alfred Crosby (used in a different context) for the plants and animals island settlers brought with them, promoting ecological homogenisation. He also says that on arrival:

[T]he Polynesian portmanteau biota consisted chiefly of three or four animals (the rat, dog, chicken, and pig) and several edible plants (for example, coconut, taro, and breadfruit) now widespread throughout the Pacific. Indeed, almost all the food crops of the islands are imports.

McNeill says they also brought fire, a great labour saving device. And that:

Upon first arrival they exploited and depleted the resources that appeared easiest to use.

An example, is that on New Zealand the Maori exploited the nine species of Moa they found and drove them to extinction.

The portmaneau biota varied because of several factors including chance. The New Zealand Maori brought only dogs and rats with them. The Easter Islanders had only rats and chickens. Plants varied too but they each began with three categories: dryland crops (especially taro, yams and sweet potato), irrigated crops (mainly taro) and tree crops (bananas, breadfruit and coconuts).

Polynesia consists of more than 1000 islands many of them inhabited. Certainly providing a variety of habitats sufficient for a vast natural history experiment.

Jared Diamond says of Polynesian societies:

Polynesians ranged from the hunter-gatherers of the Chathams, through slash-and-burn farmers, to practitioners of intensive food production living at some of the highest population densities of any human societies. Polynesian food producers variously intensified production of pigs, dogs, and chickens. They organized work forces to construct large irrigation systems for agriculture and to enclose large ponds for fish production. The economic basis of Polynesian societies consisted of more or less self-sufficient households, but some islands also supported guilds of hereditary part-time craft specialists. In social organization, Polynesian societies ran the gamut from fairly egalitarian village societies to some of the most stratified societies in the world, with many hierarchically ranked lineages and with chief and commoner classes whose members married within their own class. In political organization, Polynesian islands ranged from landscapes divided into independent tribal or village units, up to multi-island proto-empires that devoted standing military establishments to invasions of other islands and wars of conquest.

Finally, Polynesian material culture varied from the production of no more than personal utensils to the construction of monumental stone architecture. How can all that variation be explained?

Diamond says that Tonga because of its proximity to other archipelagos including outside of Polynesia, such as Fiji, was virtually an empire by the time of arrival of Europeans whereas in Hawaii the Big Island’s Chief Kamehameha used the arrival of Europeans (guns and ships) to conquer the other kingdoms.

On the colder South Island of New Zealand and the Chatham Islands the Maori reverted from agriculturalists to hunter-gatherers. Their crops could not flourish in the colder climates and at least for several generations seals and moa were easy pickings.

Environmental Variation

Diamond says that there were at least six sets of environmental variables on the islands of Polynesia that had specific consequences on Polynesian societies and which explain many of the differences between them.

Diamond goes into detail in Chapter 2 (which is quite short) beyond what is possible here. I am more interested in explaining the idea than in providing all the details.

The environmental variables are:

1 Climate: Varies from warm tropical to sub-tropical on most islands, to temperate (New Zealand) and cold sub-antarctic (the Chatham Islands). Rainfall also varies from extreme to so dry that the habitats are marginal for agriculture.

2 Geology: Varies from coral atolls, to raised limestone, to volcanic islands, to pieces of continents and mixtures of these. The volcanic islands also vary depending on the height of the mountains, which produce deep soils and permanent streams on the higher islands.

3 Marine resources: Those with shallow seas and coral reefs have abundant marine resources. Others with rocky coasts and a steeply dropping ocean bottom, such as Easter Island, Pitcairn and the Marquesas, are less productive.

4 Area combined with population density (i.e. land fertility or productivity): is another obvious variable.

5 Terrain fragmentation: Less obvious but important. Tonga with its low rolling landscape, high productivity and lack of isolation in its archipelago was conducive to developing a single political entity of 40,000 people. In the Marquesas neighbouring steep-sided valleys communicated with each other mainly by sea, making each valley conducive to forming a single political entity.

6 Isolation: Easter Island and the Chatham Islands are small and remote. Hence once colonised they developed in complete isolation. New Zealand, the Marquesas and Hawaii are also very remote. The last two did have some contact after first colonisation apparently. But, all three had significant and different political entities within to engage with and to struggle with.

Diamond’s evidence that these environmental variables did shape Polynesian societies is clear and compelling. He demonstrates this qualitatively and makes no attempt to quantify his information. Nevertheless, it would be hard to argue against it with any conviction.


Diamond’s contention that the Polynesian expansion into the Pacific is a natural experiment of history is a valid one. The scholarly research on the topic offers much detail and fleshes out the topics Diamond skims over. Nevertheless, there is still huge potential to research and quantify this more fully.

Such an important case study in human history needs to be examined in much more detail. The endeavour, however, was well beyond what Diamond was trying to achieve in Guns, Germs and Steel.

Diamond’s main source for these two chapters was Patrick Kirch an American born in Hawaii who straddles the disciplines of biology, archaeology and anthropology. Diamond primarily cites his book The Wet and the Dry: Irrigation and agricultural intensification in Polynesia 1994. The work is an important academic treatise that turns an earlier theory concerning Hydraulic Empires in Eurasia on its head, at least in Polynesia. (Although many reviews state this I’m not sure that Kirch’s intention was primarily directed at overturning the hydraulic theory and the study needs to be judged as a brilliant analysis on its own merits.)

The idea that Kirch formulated from his research on Futuna and extended to Hawaii, Mangaia and Tikopia is that it is the dry agriculture side of islands rather than the wet that are expansionary, which is counter intuitive.

There is certainly a huge element of opportunity in expanding Kirch’s detailed anthropological, archaeological and biological research and ideas with further work. However, as with most things generalist the closer you look the more complicated things become. This is evident in Kirch’s work over a lifetime. Nevertheless, such an important topic cries out for further quantification specifically concerned with verifying the implications of a natural experiment of history.

I do not think that environmental determinism as a means of rebuke and dismissal holds much merit. The environment, as defined for Polynesia by Diamond, obviously had an impact on human history. Environmental factors, biology and disease (which we have not yet covered) have obviously had a huge impact on human pre-history and history and will continue to do so.

I am not criticising mainstream history in this series. I am merely pointing out that human history on Earth is endlessly fascinating and made more fascinating by broadening the definition of history rather than narrowing it. History is not just a narration of events.

Nevertheless, let’s give the mainstream historians a win. Relying on generalisations is always tricky. There is no alternative to hard work in the field in archaeology, anthropology and biology. Similarly in history there is no getting around primary sources. Relying on secondary sources or tertiary sources is always hazardous.

Key Words: Jared Diamond, Guns germs and steel, Patrick Vinton Kirch, John McNeill, Yuval Noah Harari, Alfred Crosby, Robert MacArthur, Edward O Wilson, Theory of Island Biogeography, Natural Experiment of History, Polynesian expansion into the Pacific, environmental determinants, primary sources

Further Information

Yuval Harari

Yuval Harari was introduced in article 6 What is History: Religion. His book Yuval Noah Harari Sapiens: A brief history of humankind 2014 (first published in Hebrew in 2011) is discussed in detail in this article.

Patrick Vinton Kirch

Patrick Vinton Kirch born in Hawaii is a formidable academic. An American professor in multiple fields including archaeology, anthropology and integrative biology. He is author of many books and scholarly articles in his fields of expertise, mainly focused on the Pacific.

Kirch espoused the idea of a natural experiment of history in his first major book The Evolution of the Polynesian Chiefdoms 1984 and says he has to pay homage to even earlier efforts, such as Marshall Sahlins classic Social Stratification in Polynesia 1958, which he says laid the groundwork for his own research.

Wikipedia gives an overview on Kirch

As does the UC Berkeley Anthropology page on Kirch which also has a link to his CV with a much more comprehensive publications list.

The Kirch publications of particular interest here are:

  • The Evolution of the Polynesian Chiefdoms 1984 where he introduced and developed the idea that the Polynesian cultures represent a sort of grand natural experiment of history in terms of a common culture adapting to a range of island environments (mentioned above).
  • The Wet and the Dry 1994 which Diamond cites in his Further Readings in Guns, Germs and Steel and was my first introduction to Kirch’s work. Over a five year period I used Diamond’s Further Readings as an introduction to a large amount of scholarly writing in an array of fields with which I was unfamiliar.
  • Controlled Comparison and Polynesian Cultural Evolution in Jared Diamond and James Robinson eds. Natural Experiments of History 2010. This is a scholarly short essay on the topic.

Robert MacArthur and Edward O Wilson

The Theory of Island Biogeography by Robert MacArthur and Edward O Wilson 1967. This is a pivotal book in biology and had a sensational impact in its time. I was impressed that Patrick Kirch says: I still turn back to it from time to time (pers. comm.). I wish I was as disciplined.

Jared Diamond’s return to the topic of Natural Experiments of History

In my conclusion I said:

The scholarly research on the topic offers much detail and fleshes out the topics Diamond skims over. Nevertheless, there is still huge potential to research and quantify this more fully.

and further on:

Nevertheless, such an important topic cries out for further quantification…

I think that Diamond himself thought that the topic deserves more detailed exploration, as evidenced by Jared Diamond and James Robinson eds. Natural Experiments of History 2010. However, although there are thought provoking contributions in this collection of essays, the book hardly does much to advance the concept with the type quantification that I envisage.

John McNeill

John McNeill in Of Rats and Men: A Synoptic Environmental History of the Island Pacific Journal of World History 5: 299-349, 1994 is another who has made a major contribution to the issues discussed in my conclusion. His scholarly article is a study of the biota of the Pacific islands before the Polynesian expansion into them; a study of the changes brought about by the Polynesians; and, a study of the changes brought about post-Captain Cook by the European colonisation of the Pacific.

John McNeill was cited in my article 9 Guns, Germs & Steel Overview for his review of Guns, Germs and Steel in 2001.

Alfred Crosby

Alfred Crosby introduced the concept of portmanteau biota in Ecological Imperialism: The Biological Expansion of Europe, 900-1900, 1986 in the context of European expansion into the rest of the world.

Alfred Crosby is perhaps best known for his book mentioned in article 1 What is History: Introduction: The Columbian Exchange: the biological and cultural consequences of 1492, 1972.

Further Readings in Guns, Germs and Steel

I gave Siria in Goodreads a serve in 1 What is History: Introduction for giving Guns, Germs and Steel  a low rating because:

When it comes to assessing the reliability of Diamond’s arguments, the fact that there are no footnotes and no full bibliography make that a somewhat difficult task…

I disagreed with this vehemently (at which she took umbrage in Goodreads) and said:

Diamond’s book is well-indexed and instead of a bibliography he includes a section entitled Further Readings, which I found a breath of fresh air. In Further Readings Diamond provides his references in a lucid English description of his sources chapter-by-chapter, with complete formal citations. I found that it made his research very accessible.

Now, perhaps I owe Siria a slight apology. Although from my point of view I found Further Readings refreshing as a reader, it does provide Diamond with some latitude in deciding what to credit and possibly what to gloss over. For example, in the current topic I as a reader was left to assume that the Polynesian expansion as an experiment in history was his original idea rather than the idea of other scholarly researchers on the Pacific. One could assume that Diamond was being less than generous in crediting sources on this occasion.

However, before pointing the finger at Diamond. I should mention generalist writing is quite difficult. One must gloss over many things and often omitting to cite the source of your inference may be inadvertent or a mistake.

I am certainly not one to cast the first stone, because in my own articles my thoughts are merely stones skittering across deep lakes of knowledge and I am most unlikely to acknowledge everyone that I should. Although I do try hard not to.

Big-picture history

Looking at history from different perspectives or perhaps from a big-picture overview seems to me to be a natural way of looking at things. After all, that is the basis of my What is History? series. But, perhaps there are other ways of seeing.

I was brought up short by John McNeill (pers. comm.) when he said:

Big-picture history is indeed fascinating.  It does seem to be male-dominated, which I don’t know how to explain.

I have no idea why it should be a male-dominated enterprise. Indeed, it gives me an uneasy feeling and goosebumps.

The other articles in my What is History? series are 1 Introduction 2 Sleep Patterns, 3 The Medieval Mind, 4 Love,  5  EH Carr Historians & their facts, 6  Religion 7 EH Carr Causation in History, 8 EH Carr History as Progress, 9 Guns, Germs & Steel Overview and 11 World Economic History.

Posted in Christchurch, New Zealand



  1. Author

    Hi Peggy

    Thanks for your comment as always. This is a fascinating area of history. Although I think Diamond should have attributed the idea to others. Having a few teething problems with my site regarding this post. Until today it has only been visible to those who follow the blog. We are back from New Zealand today and hopefully remedying this. Catch up soon.

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