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WHY DO SOME SOCIETIES COLLAPSE while others survive? History is replete with examples of complex civilisations that have nevertheless fallen: the Anasazi of the U.S. south-west, the Maya in Mexico's Yucatan, Easter Island in the Pacific, Angkor Wat in Southeast Asia, Great Zimbabwe in Africa, the Fertile Crescent societies of the Middle East, and the Harappan in the Indus Valley.
These are all societies that destroyed their environments and ultimately themselves, in part by undermining the natural resources on which they depended.
Take the Easter Islanders, a Polynesian people who settled an island that was originally forested, and whose forests included the world's largest palm tree. Over centuries, they gradually chopped down that forest to use the wood for canoes, firewood, transporting statues, raising statues and carving, and also to protect against soil erosion.
Eventually they chopped down all the forests, which meant they ran out of canoes, they could no longer erect statues, there were no longer trees to protect the topsoil against erosion, and their society collapsed in an epidemic of cannibalism that left 90 per cent of the islanders dead.
When I tell this story to my students at the University of California in Los Angeles, where I teach, the question that most intrigues them is one that hadn't registered to me: how could a society make such an obviously disastrous decision to cut down all the trees on which they depend?
What did Easter Islanders say as they were cutting down the last palm tree? Were they saying, "Think of our jobs as loggers, not these trees?" Were they saying, "Respect my private property rights?" Surely Easter Islanders must have realised the consequences of destroying their forest. One wonders whether people of the next century – if there are still people alive – will be equally astonished about our blindness today.
It's a question that astonishes historians too. The most cited book about the collapse of societies is by Joseph Tainter, entitled The Collapse of Complex Societies. In discussing ancient collapses, Tainter rejected the possibility that they might be due to environmental mismanagement because it seemed so unlikely to him.
He argued it was "reasonable to assume" that as resources dwindled, the leadership caste of a complex society would take rational steps to resolve the problem, saying "…Dealing with adverse environmental conditions may be one of the things that complex societies do best". Tainter concluded that the collapses of ancient societies couldn't be due to environmental mismanagement, because they would never make such bad mistakes.
Yet, it's now clear that these societies did make woeful mistakes. Both Tainter and my undergraduates have identified an intriguing phenomenon: the failure of group decision-making by whole societies, or governments, or smaller groups, or businesses.
It's similar to failures in individual decision-making: people make bad decisions – they enter bad marriages, make bad investments, and their businesses fail. But societies are more complex than individuals, and there's no easy answer to why they fail. However, I think there's a road map of factors that can identify when a society, or a group, is staring failure in the face.
First, a group may fail to anticipate the arrival of a problem. Second, the group may fail to perceive it when it arrives. Third, having recognised it, they fail even to try to find a solution. Finally, they may try to solve the problem but ultimately fail.
Societies may do disastrous things because they didn't anticipate a problem before it arrives. They may have no prior experience of such problems, and are therefore ignorant of the potential threat. Consider forest fires in the U.S. west: my family and I spend part of our summers in Montana, and each year when we fly in, I look out of the window to see how many forest fires I can see.
Forest fires are large and widespread in the mountainous U.S. west; such large fires are unknown in the eastern U.S. and Europe. When settlers from the east and Europe arrived in Montana and a fire arose, their reaction was, of course, to try and put it out. They had had no previous experience of fires in a dry environment, where trees that fall into the understorey don't rot away as they do in wet Europe and the eastern U.S., but accumulate on the forest floor as 'fuel'.
Australians live in a similar dry environment. They've known for years that frequent small fires burn off the fuel load; if you suppress those small fires, when a fire eventually starts, it may burn disastrously out of control. The best way to deal with fires in dry forests is to let them burn, and burn out; that way there's no build-up of fuel to feed a wildfire.
But the new arrivals had no prior experience with huge forest fires, and the idea of allowing a fire to burn was so counter-intuitive that it took the U.S. Forest Service 100 years to realise the problem and change strategy. A society has to recognise the problem before it can deal with it.
Another reason why a society may fail to anticipate a problem is that they may have prior experience – but it has been forgotten. A society with little writing or records isn't going to preserve oral memories of something that happened long ago.
The Classic Lowland Maya eventually succumbed to a drought about in around the year 800. There had been previous droughts in the Maya realm, but they could not draw on that prior experience because, although the Maya had some writing, their records merely preserved the history of royal conquests, not droughts.
Mayan droughts recur at intervals of 208 years, so the Maya in 800 – when the big drought struck again – did not, and could not, remember the drought of 592.
In modern literate societies, even though we have writing, that does not mean we can draw on prior experience. We too tend to forget things. People of the developed world today – and particularly Americans – behave as if they've forgotten about the 1973 oil crisis.
For a year or two after the crisis, Americans avoided gas-guzzling vehicles; but then quickly forgot that knowledge – despite having a mass of newspaper articles, books, historical records, and lengthy television footage of the impact of the oil crisis.
In the 1960s the city of Tucson in Arizona went through a severe drought, and the citizens swore that they would manage their water better; but within a decade or two, Tucson had fallen off the rails and reverted to its water-guzzling ways, even building golf courses.
Then there's 'reasoning by false analogy', another cause for why a society may fail to anticipate a problem before it develops. When humans are in an unfamiliar situation, we fall back on reasoning based on old, familiar situations. That's a good way to proceed if the old and new situations are truly analogous; but can be dangerous if the situations are only superficially similar.
Take Norwegian Vikings who migrated to Iceland from 871 AD. Their familiar homeland of Norway has heavy clay soils ground up by glaciers: those soils are so heavy that, if the vegetation covering them is cut down, they are not blown away.
Unfortunately for the Viking colonists of Iceland, the local soils are as light as talcum powder: Icelandic soil was not a product of glacial grinding, but of the wind dispersal of light volcanic ash from volcanic eruptions. So when the Vikings cleared Icelandic forests to create pasture, the ashen soils blew away. Within a few generations, half of Iceland's topsoil had eroded into the ocean. Other examples of reasoning by false analogy abound.
Societies can also fail to perceive a problem that has actually arrived. The history of collapsed civilisations reveals failures of recognition have at least three distinct causes, all of them relatively common in the world today.
First, a problem may not be noticed because its origins are literally imperceptible. For example, the nutrients responsible for soil fertility are invisible to the naked eye, and have only recently become measurable via chemical analysis.
In Australia, parts of the U.S. south-west, the island of Mangareva in French Polynesia, and many other locations, most of the nutrients had already been leached out of the soil by rainfall before people arrived. When human settlers began growing crops, the remaining nutrients were quickly exhausted and agriculture rapidly failed.
Such nutrient-poor soils often bear deceptively lush-appearing vegetation: it's just that most of the nutrients in the ecosystem are held by the plants rather than the soil, so the nutrients vanish when the vegetation is cut down. There was no way that the first colonists of Australia or Mangareva could have known about soil-nutrient exhaustion before they started clearing vegetation.
A more common reason for failing to perceive a problem is that it may be a slow trend that is hidden by wide fluctuations. The best example is global warming: we now realise that temperatures around the world have been slowly rising for decades, due in large part to changes in the atmosphere caused by humans.
However, it is not the case that the climate each year is 0.17°C warmer than the previous year. Temperature fluctuates widely from year to year: three degrees warmer one summer, then two degrees warmer the next summer, down four degrees the following summer, down another degree the next summer, then up five degrees, and so on. With such fluctuations, it takes a long time to recognise the upward trend.
That's why it was only a few years ago that the last professional climatologist, previously sceptical of global warming, became convinced. Many political leaders still say we need more research. Medieval Greenlanders had similar difficulties recognising their climate was slowly becoming colder, and the Maya of the Yucatan had trouble discerning that their climate was gradually becoming drier.
The term 'creeping normalcy' (or normality) is often used to describe such slow trends buried within noisy fluctuations. If a situation is getting worse only slowly, it is difficult to recognise that this year is worse than last year, and each successive year is only slightly worse than the year before; what you consider 'normal' shifts only gradually and almost imperceptibly. It may take a few decades or a long sequence of such slight year-to-year changes before someone suddenly realises that conditions were much better several decades ago.
The final frequent reason for failure to perceive a problem is 'distant managers', which can often happen in a large society. Administrators can be so far removed – geographically and otherwise – from local conditions that they do not notice changes that might be apparent to someone on the ground.
The third stepin my road map of failure is perhaps the most common and most surprising one: a society's failure to make even a rudimentary attempt at solving a problem it has recognised.
Such failures frequently arise because of what economists term 'rational behaviour': they stem from clashes of interest between people. Some people may reason correctly that they can advance their own interests by behaviour that is harmful to other people. Economists term such behaviour 'rational', even while acknowledging that morally it may be rather naughty.
The perpetrators – beneficiaries of big, certain, immediate pro fits from the bad status quo – are likely to get away with their rational bad behaviour because they are typically concentrated (few in number) and highly motivated. The losers meanwhile are diffuse (the losses are spread over large numbers of individuals) and lack motivation because they receive only small, uncertain, distant profits from halting or reversing the bad behaviour of the minority.
A typical example of rational bad behaviour is "good for me, bad for you and for the rest of society". To put it bluntly, 'selfishness'. A few individuals may correctly perceive their self-interest to be opposed to the interest of the majority.
For example, until 1971, mining companies in Montana tended to just dump their toxic waste of copper and arsenic into rivers and ponds because the state of Montana had no law requiring them to clean up after abandoning a mine. And after the Montana legislature did pass such laws, mining companies discovered they could still extract the valuable ore and avoid the expense of cleaning up by declaring bankruptcy.
The result has been billions of dollars of clean-up costs borne by the citizens of the United States and, in particular, Montana. The miners had correctly perceived that they could advance their own interests and save money by making their mess and leaving the clean-up burden to society.
One particular form of such clashes of interest has received the name 'tragedy of commons'. It refers to a situation where many people harvest a communally owned resource – such as fish in the ocean, or grass in common pastures – but in which there is no effective regulation that specifies how much of the resource each individual can draw.
Under those circumstances, individuals can correctly reason, "If I don't catch that fish or graze that grass, some other fisherman or herder will, so it makes no sense for me to be careful about over fishing or overharvesting". The correct rational behaviour is to harvest before the next person can, even though the result is depletion or extinction of the resource, and hence harm for society – and all of the fishermen and herders – as a whole.
Clashes of interest also arise when a group has no long-term stake in preserving a resource. For example, much commercial harvesting of tropical rainforests today is carried out by international logging companies, which lease land in one country, cut down all the rainforest, and then move on to the next country selected for harvesting.
International loggers have correctly perceived that as soon as they have paid for the lease their interests are best served by clear-cutting their leased land without regard to its future use or rehabilitation.
In this way, loggers have destroyed most of the forest in the Malay Peninsula, Borneo, the Solomon Islands and Sumatra; the same is likely to happen in the Philippines, Papua New Guinea, the Amazon, and the Congo Basin. In such cases, the consequences are borne by the next generation; and the next generation cannot vote or stage protests.
Failures also occur when the interests of a decision-making elite conflict with the interests of the rest of society. The elite are particularly likely to do things that profit them but hurt everybody else if they can somehow insulate themselves from the consequences of their actions.
Such clashes are increasingly frequent in the United States, where the high-flyers and the wealthy live in gated communities inhabited by people like themselves; their conduct and decisions impact on a society with which they have little connection. Enron's executives calculated they could gain huge sums of money for themselves by looting the company and harming the rest of society, and that their gamble was likely to go undetected. They almost succeeded.
Such failures are less likely in societies where the elites cannot insulate themselves from the consequences of their decisions. Take Netherlands, a modern nation with the highest proportion of citizens belonging to environmental organisations. I never understood the reason for this national interest in the environment until I was visiting a few years ago and raised this question with my Dutch colleagues as we were driving through the countryside.
"Just look around you," they answered. "The land here is 7m below sea level. It was once a shallow bay of the sea that we surrounded by dikes and then drained with pumps to create low-lying land we call a 'polder'. We have pumps that pump out the water that is continually leaking into our polders through the dikes."
"If the dikes burst, the people in the polder drown. But it is not the case that the rich Dutch live on top of the dikes, while the poor Dutch are living down in polders. If the dikes burst, everybody drowns, regardless of their wealth."
"That was what happened in the terrible floods of February 1953, when high tides and storms drove water inland over the polders of Zeeland and nearly 2,000 Dutch drowned. After that disaster, we all swore, 'Never again!' and spent billions building reinforced barriers against the water."
In Netherlands, the people in power know they cannot insulate themselves from their mistakes, and that they have to act in ways that will do the maximum good for as many people as possible.
As outlined in the previous examples, societies sometimes fail to solve a problem – even though it's been recognised – because maintaining the status quo is good for the perpetrators or the power brokers, even if it's not so good for everyone else.
In contrast, there are also failures to attempt to solve perceived problems that are clearly harmful for everybody. This 'irrational behaviour' often arises when we are torn by clashes of values: we may be strongly attached to a bad situation because it is favoured by some deeply held value that we admire.
Religious values are especially deeply held and often the cause of disastrous behaviour: much of the deforestation of Easter Island had a religious motivation – to obtain logs to transport and erect the giant stone statues that were the basis of the island's religious practice.
Today, one reason why people in Montana have been reluctant to solve the obvious problems accumulating from mining, logging and ranching is that these industries were formerly the pillars of the local economy, and as a result they became bound up with the pioneer spirit and with Montanan self-identity.
Irrational failures also frequently arise from clashes between short-term and long-term motives. Billions of people today are desperately poor and able to think only of food for the next day. Poor fishermen in tropical reef areas use dynamite and cyanide to kill and catch reef fish, in full knowledge that they are destroying their future livelihood. They continue to act in this way because they feel they have no alternative food source in the struggle to meet the short-term needs of their children.
Governments also regularly operate on a shortterm focus: they feel overwhelmed by imminent disasters, so that they pay attention only to those crises that have reached flashpoint, and feel that they lack time or resources to devote to long-term problems. I've heard it said that political leaders in Washington now have a '90-day focus': they only talk about those problems with the potential to cause a disaster within the next 90 days.
Economists rationally justify these irrational focuses on short-term profits by 'discounting' future profits: that is, they argue that it may be better to harvest a resource today than to leave some of the resource for harvesting tomorrow, because the profits from today's harvest could be invested, and the accumulated interest between now and a harvest of exactly that same quantity of resource in the future would make today's harvest more valuable than the future harvest. This may well work in investment-banking circles but is it any guide to running a sustainable society?
A further possible cause of failure to attempt to solve a problem can be found in a particularly human trait: psychological denial. It's a technical term with a precise definition in individual psychology, which has since spread into pop culture.
If there's something that arouses an unbearably painful emotion, you may subconsciously suppress it or deny perception of it in order to avoid the unbearable pain – even though the practical results of ignoring your perception may prove ultimately disastrous, even fatal. The emotions most often responsible are terror, anxiety and sadness. Typical examples include refusing to think about the likelihood that a loved one may be dying, because the thought is so painful.
It happens in whole populations too. Consider a narrow deep river valley below a high dam; if the dam burst, the resulting flood would drown people for a long distance downstream. People living downstream have been polled about their feelings: are they concerned about the dam bursting? It's not surprising that fear of a dam burst is lowest far downstream, and increases among residents increasingly close to the dam.
Surprisingly, though, in populations that live within a few kilometres of the dam – where fear of the dam's breaking might be highest – pollsters find that the concern falls off to zero! That is, the people living immediately under the dam – who are probably most certain to be drowned – profess no concern.
It's a classic case of mass denial: the only way of preserving one's sanity while living immediately under the high dam is to deny the finite possibility that it could burst. Psychological denial may also explain why some collapsing societies fail to face up to the obvious causes of their collapse – even when the causes are plain to see and tower above them.
Finally, there is the failure to succeed in solving a problem that a society actually tries to solve. The problems may be too large, too difficult or require more resources than a society can allocate. Often, though, we fail to solve a problem because our efforts are too little and begun too late.
Australia is a case in point: it has suffered tens of billions of dollars in agricultural losses, as well as the extinction or endangerment of most of its native small mammal species, because of the introduction of European rabbits and foxes for which there was no close native counterpart in the local environment.
Foxes have been widespread over the Australian mainland for more than a century, but until recently they were absent from the island state of Tasmania, because foxes could not swim across the wide, rough seas between the mainland and Tasmania.
Unfortunately, a few years ago someone surreptitiously and illegally released 32 foxes on the island – perhaps for their foxhunting pleasure or to spite environmentalists. Those foxes now represent a large threat to Tasmania's lamb and chicken farmers, as well as the island's native wildlife.
When local environmentalists became aware of the fox problem about March 2002, they urged the state government to exterminate the creatures quickly, before the fox-breeding season began in July. Once those 32 foxes had produced litters and those litters had dispersed, the interlopers would be far more difficult to eradicate.
Unfortunately, the state government debated and delayed. In June, it finally committed funds to eliminating the foxes. A golden opportunity was missed, and now the foxes are in danger of displacing the Tasmanian devil, found exclusively on the island and the largest carnivorous marsupial in the world.
Meanwhile, the devil population is now being ravaged by a mysterious facial-tumour disease, which has triggered a dramatic collapse of the animal's population – and created an ecological niche for the foxes. The combination raises the real possibility that the Tasmanian devil may become extinct.
HUMAN SOCIETIES and even smaller groups – cities, corporations, governments – all can make disastrous decisions for a whole sequence of reasons: failure to anticipate a problem, failure to perceive it once it has arisen, failure to attempt to solve it after it has been perceived, and failure to succeed in attempts to solve it.
It may sound pessimistic, as if failure is the rule in human decision-making. That is not always the case, and many human societies have survived and prospered against huge odds because they have anticipated, perceived, tried to solve, or succeeded in solving their environmental problems.
The Inca Empire, 18th-century Japan, 19th-century Germany, the New Guinea Highlanders, and the paramount chiefdom of Tonga – all of these groups and societies recognised the risks that they faced from deforestation, and all adopted successful reforestation or forest-management policies.
Understanding the reasons for the failure and collapse of different societies is essential to making successful decisions for our own. If we understand the reasons why societies make bad decisions, we can use that knowledge as a check list to help make good decisions. We may also become more conscious of how others have failed, and of what we need to do in order to get it right.
Jared Diamond is a renowned evolutionary biologist and a professor of geography at the University of California in Los Angeles. A Pulitzer Prize-winning author, his most recent book is Collapse: How Societies Choose to Fail or Succeed, published by Penguin. This is an extract of his Lewis Thomas Prize Lecture delivered at New York's Rockefeller Institute in March 2003.
