Human Cultural Evolution: In Favor of the Boserup Theory
by Lynden S. Williams
This is the last of a three part series on human cultural evolution. First we examined the ‘supply-side’ or Malthusian Theory of cultural evolution; second we explored the ‘demand-side’ or Boserup Theory. In this third section I will argue in favor of the demand-side or Boserup Theory and discuss some of the implications of that perspective for human history. I strongly recommend you read Parts One and Two prior to reading this section.
The Boserup Theory
The Boserup Theory holds that increases in demand are usually necessary to stimulate major changes in human culture. As explained in detail in the previous section, increased production usually requires intensification of land use, and the Law of Diminishing Returns generally results in increased labor requirements when land is used more intensively; the Law of Least Effort acts to discourage changes that require increased labor input unless increased demand requires that change. In addition, living at higher densities and a more sedentary lifestyle promotes exchange of ideas and formal education. Therefore, population growth (or other increased demand) is the cause for intensification of land use rather than the result, and it may give rise to innovation that could increase per capita productivity. For most of pre-human and human history, increases in demand resulted from population growth, and population growth continues to compound increasing demand in those societies where per capita consumption is increasing. Thus, in contrast to the Malthusian Theory which postulates innovation and discovery as necessary to allow or stimulate population growth, the Boserup Theory holds that population growth (and by extension other increases in demand) is usually the cause for evolution of a more productive economy.
Boserup (in her 1965 book) focused almost exclusively on intensification of agricultural systems, showing that increasingly intensive farming systems (forest fallow, bush fallow, short fallow, annual cropping, & multi-cropping) is an historical sequence forced by increased demand, mostly resulting from population growth. It is suggested here that other stages in human cultural evolution (the omnivorous, habitat, and urban-industrial revolutions) can also be explained by the same process. When we examine these changes in diet, habitat, farming, and industrial development, it becomes clear that the wisest and most powerful would not have been those most likely to have initiated them. Rather, it would have been those individuals and groups who were least able to defend their resource base or survive in the previous environment that would have been forced to make those changes.
The Omnivorous Revolution
One of the first significant changes in human culture must have been the change from vegetarian to a diet that included meat. All other primates remain mostly or totally vegetarian. What caused our species of primate to make that change? It must have taken place over many thousands of years given the need for the digestive system to evolve those changes required to process meat. And, that change must have been a very painful one—probably beginning with occasional consumption of carrion. Could that change have been caused by other than insufficient vegetable resources to meet demand? Could those sources of increased demand have been caused by other than population growth or inability to defend sufficient territory for an adequate vegetarian resource base?
The change to an omnivorous diet resulted in very significant advantages over the longer term. Vegetarians must spend most of their time gathering and eating; carnivores by contrast need to spend a relatively small portion of their time eating—once per day in the case of most large carnivores. As omnivorous creatures humans were able to greatly reduce the amount of time spent gathering and eating. The need for meat required methods of procuring it, which for humanoids that could only mean learning to use tools. Thus, the changed diet provided the motive to make those weapons and other tools needed to pursue that new lifestyle. When omnivorous primates come into conflict with vegetarian primates, they win!
The Habitat Revolution
The next significant stage in human culture resulted from the movement of humanoids into the tropical grasslands. Except for a few primates, forest animals are usually quite small (mostly arboreal where most of the annual production in the forest takes place). Suitable weapons for hunting these animals are blowguns and bows & arrows or light spears. Those weapons would be completely inadequate to kill the large grazing animals in the seasonally dry grasslands or allow humanoids to defend themselves against large grassland predators. What, other than population pressure within the tropical forest regions would have forced humanoids onto the grasslands, and who, other than those unable to defend their territory within the forest region, would have made that move?
Once again, the move to the tropical grassland was accompanied by very significant advantages over the longer term. Grassland humanoids developed weapons (had to develop weapons) far superior to those who inhabited the forest. Tropical grasslands are far more extensive, allowing for rapid population growth. And grassland animals are larger, requiring fewer kills to provide subsistence for the family. When grassland humanoids confront forest humanoids, they win!
The next significant stage in human cultural evolution was movement of people into the seasonally cold latitudes. Absent clothing and controlled fire even a slight decline in temperature would cause great discomfort or even death for humans. What, other than population pressure within the tropical grasslands would have forced humans into the seasonally cold regions, and who, other than those unable to defend their territory within the savannas, would have made that move? Once humans learned to survive the winter season, the pace of the spread poleward must have increased dramatically. In just a few hundred thousand years humans inhabited and dominated almost the entire ice free land area of the earth.
The move to seasonally cold regions was accompanied by some very significant advantages. For the first time humans were completely removed from the hot wet environment where their disease organisms evolved. Humans emerge as ‘exotic species’ with few natural enemies, including diseases —and take their prey by surprise. When mid-latitude humans confront humans in the tropics, they win!
Evolution of Agriculture
The evolutionary process of mutually beneficial symbiosis between life forms is not confined to humans. Animals tend to spread the seeds of those plants they consume. Plant-animal symbiosis usually resulted in a tasty fruit with a bitter or toxic seeds, so that the consumer will spit them out (and thus plant them). Alternatively seeds can be small and indigestible so they can pass through the digestive system of the consumer and come out viable and fertilized—for example, the bird/berry bush and the human/tomato symbioses.
The evolutionary process that resulted in domestication of plants and animals did not stop ten thousand years ago; indeed, I have witnessed several examples of the process of human/plant (or animal) symbiosis in progress. Once in the Kekchi Maya community I accompanied my friend to his “mata hambre” (kill hunger) crop along the side of a nearby stream. His main crop was a long fallow slash & burn field in the forest, but he would plant this crop annually along that portion of the stream that was flooded each year bringing a fresh layer of rich silt, as a reserve in case the main crop failed. The crop was perhaps an acre of corn, intercropped with squash. As we walked through the field he would take out weeds with his machete (which he always carried with him). I noticed that there was one ‘weed’ that he did not cut, and asked him about it. I think he called it ‘calalu’, (but can’t be sure and don’t think it is the same plant of West African origin that I get on Wikipedia online; wish I had keep better notes!) I asked if he had planted it; he responded no, it is a volunteer, but we let it grow because it has a ‘very nice leaf’ (used as a condiment and in concentration as a medicine for children with dysentery). He said, we Maya have always known about this plant; it puts out seeds on top in April, and as we pass by we just grab a handful and scatter them about, so that next year there will be more of them.
Once I accompanied the same friend to his forest plot to help bring home a load of corn. They build sheds with thatch roofs about a foot and a half off the ground, near their plots to store their corn. As we approached the shed a very large snake emerged from under and crawled to a nearby bush; my friend did not seem to notice the snake. “You did see the snake, didn’t you?” I asked in near disbelief. You mean that snake? “Yes!” Oh he lives under the corn shed; he kills the rodents and birds that come to eat my corn. And added: all corn sheds have a snake under to keep the pests away. “Really? Is it the same species of snake”? Yes. “So you guys go out and find one and put him under there?” No, we just build the shed and the snake will find it. I knew I was witnessing evolution big time. If the Maya continued that practice for a few more thousand years (they won’t; population growth will not allow them to continue forest fallow agriculture) that species of snake would become dependent upon Maya sheds, just as the Maya are already dependent upon the snake to protect their corn. Note that the snake knew the human did not want him around when he came for corn, but also knew he did not have to move too far away to hide—given the mutual beneficial relationship, the killer human will not come after him. On another occasion in an East Indian community south of the Maya village, I saw a large snake (can’t be sure it was the same species) crawling toward a house which was also about two feet off the ground; it had a house cat clinging to its tail but didn’t seem to mind. The woman of the house ran out and used a broom to shoo the snake away. [Hell, I thought it was a corn shed, the snake thought.]
Many Kekchi Maya farmers who practiced forest fallow maintained a hunting stand at the edge of their plot which was used to hunt (using a shot gun) wild animals (mostly a forest species of peccary, and tepezcuintle, a rodent the size of a very large house cat) that come by at night to eat the crops. I was not able to determine whether the primary purpose was to protect the crop or to procure the meat. Some of the farmers would plant a special crop around their plot meant to attract those animals; again, I do not know if the reason was primarily to discourage the animals from eating the main crop or to attract them. When they killed an adult animal that had young, the young were gathered when possible and brought back to the village to be raised for food. Whatever the primary reason, these animals provided a very tasty meal. The peccary were simply confined with (European) pigs that seemed to get along fine with them. Young tepizcuintle were penned separately and fed, but would sometimes reproduce in captivity. These animals are obviously semi-domestic. I speculate that introduction of the fully domestic European pig eliminated much of the pressure to continue the overt domestication process with the peccary and tepezcuentle.
The Agricultural Revolution
The evolutionary process animal/plant symbiosis can be greatly speeded up when gathering of fruits and plants is very intensive, and especially when the gatherer is aware of the fact that seeds will produce new plants and begins to deliberately spread those seeds that are most desirable. As the human population increased beyond the capacity of the natural landscape to support it, humans began to transform the natural landscape to a cultivated landscape. The agricultural revolution was a very significant step in human cultural evolution. That process occurred over many thousands of years as ever more intensive gathering led to the evolution of cultigens.
But why would people give up their hunting and gathering life style and settle down with the weeds and their animal equivalents (lice, rats, roaches, etc.) that evolve to take advantage of the more permanent dwellings that farmers must have, to achieve an increased work load and a poorer diet? Who, other than those unable to secure sufficient wild resources, would be forced into that situation?
Once again, agriculture provides important advantages over the long term. The potential for population growth is greatly increased. Agricultural people are sedentary and thus have a motive to construct elaborate living quarters. Living at higher densities increases the exchange of ideas and encourages formal education, including development of a system of writing. Agriculture appears to be essential for the innovations that led to bronze, iron, and later steel, tools; indeed, the development of ‘civilizations’ all depended upon high density settlements made possible by agriculture. When agricultural people confront hunter-gatherers, they win!
The Urban-Industrial Revolution
The urban-industrial revolution was coincident with rapid population growth in a region that experienced severe population pressure. The insular location of England conveyed some significant advantages. England was close enough to one of the world’s centers of civilization to acquire much of the culture, but sufficiently remote to be able to avoid the periodic ravages of invading hoards and contagious diseases. But that island was successfully invaded by the Romans and later by the Normans, and there was clear danger of another invasion from the mainland. Military power at the time depended upon the number of steel covered man/animal units a country could put into the field. The potential human and animal populations was a function of crop and pasture land, and France had a supply of crop and pasture land that England could not match. At that time steel was made with wood charcoal, and England had essentially deforested their country in an attempt to match the supply of steel produced in France. The existence of coal in England was known; indeed, coal had been used for space heating since Roman times. But no known fire box for steel production would withstand the greater heating properties of coal, so that making steel with coal was thought to be impossible. It is clear that population pressure, deforestation, and the imminent threat of invasion from the mainland played an important part in what was to become the first urban-industrial country on earth. The English built that fire box and quite suddenly became the most powerful country on earth.
Prior to the industrial revolution power was mostly disbursed over the countryside, dependent upon availability of crop and pasture land. In sharp contrast, coal could be cheaply offloaded from river barges at strategic points; it was necessary for people to cluster at those points in order to have access to this new form of energy. Unfortunately, these new cities were extremely unhealthy with sewage running in open ditches, and characterized by extreme poverty; indeed, life expectancies in 18th and 19th Century cities was about 10 years lower than in rural areas. In short, people would not voluntarily move to the city. However, feudal lords owned virtually all the land and they wanted to increase their wool production given the growing market for textile production. They instituted the ‘enclosure’ movement which forced large numbers of peasant farmers to migrate to cities. Once again, over the longer term there were many very positive advantages that would accrue from the urban-industrial process. When urban-industrial people confront agricultural people, they win!
Increased Speed of Change and Geometric Population Growth
Each stage in the process of major culture change was accomplished much more rapidly, but associated with exponential growth in the population. The ‘Habitat Revolution’, in which humans moved from the hot-wet tropics of the Old World into higher latitudes and eventually populated all of the ice-free land surface of the earth occurred over a period of hundreds of thousands of years and increased the population from a few hundred thousand to several million. The ‘Agricultural Revolution’, in which humans changed from dependency upon hunting & gathering of mostly wild plants and animals to dependency on domestic plants and animals took place over a period of several thousand years and increased the population to several hundred million. The ‘Urban-Industrial Revolution’, in which much of the human population agglomerated into cities to produce manufactured products and services has taken place in just the past few hundred years and has increased the population to several billion.
The Demand-Side Theory of Human Cultural Evolution
It follows from the Boserup Theory that population growth is a prime driver, perhaps the prime driver, of human cultural evolution. Absent population growth humans would have had no motive for the change to an omnivorous diet and extending their habitat into the savannas of Africa and seasonally cold latitudes of Europe. Population growth in the tropical rainforest region of central Africa would have provided the incentive to drive weaker clans into the seasonally dry tropical grasslands where their tools and weapons would have been of little use and where they would face fierce predation from large grassland carnivores. However, that is precisely the challenge that would have provided the stress of experience essential for development of tools and weapons appropriate for hunting and defense in the tropical grasslands. Likewise, only those clans unable to defend sufficient space in the savannas to feed their growing populations, would have been pushed into the seasonally cold latitudes where they would be motivated to develop clothing (wrap themselves in animal skins) and learn to control fire.
One might attempt to counter this argument by noting that clans or groups living near the margins of the tropical forest regions would have periodically experienced the need for tools and weapons needed to live in the seasonally dry grasslands. This counter argument begs the question; why would people have chosen to live in marginal areas unless population growth resulted in pressure within the more suitable area, and wouldn’t it have been those least able to defend their space within the core area that would have been pushed to the margins?
This suggests the statement some of the last shall be first is very relevant to human cultural evolution. The word ‘some’ is critical; most families and clans forced into the seasonally dry grasslands and seasonally cold latitudes almost certainly perished. However, the reward for the survivors was incredible, and certainly unthinkable by those who remained behind in the more suitable region. Population growth beyond the support capacity of the hunting and gathering lifestyle appears to have caused people to adopt agriculture. Likewise, the urban-industrial economy appears to have been a necessary change that was forced on people who had no viable alternative.
Thus we have a complete reversal in the cause for innovation. The idea that people developed weapons and clothing, and learned to control fire, in the hot wet tropics where those innovations were not needed is rather farfetched. Likewise, the voluntary migration of the strongest and wisest into seasonally dry or cold environments was most unlikely. The Boserup Theory suggests that innovation was an act of desperation on the part of those groups who faced the stress of experience in an environment that is incompatible with known methods of procuring a livelihood.
Throughout most of human history increased demand would have been driven almost exclusively by population growth. Goods and services other than those required for survival were mostly unknown until very recently. Even after per capita consumption began to increase, a growing population would compound the increase in demand. The rapid decline in population growth produced by the ‘demographic transition’ was coincident with rapid economic development in many countries. We must remember, however, that rapid population decline produces a generation in which the working age population is very large in comparison with the number of children and elderly requiring care and support. This very favorable demographic situation often resulted in a very rapid expansion in per capita consumption, or said another way, rapid economic development. The U.S. economy received a second jolt when the ‘baby boom’ generation reached working age from 1960 through 1985; most Latin American economies are now experiencing the same rapid expansion, as are many countries in Asia—notably China and India. Most African countries now have the same opportunity, but it is not clear that the political/economic systems in those countries will allow them to take advantage of their very positive age structure. However, after the ‘boom’ generation begins to retire the economic impact of low population growth is reversed. The ratio of workers to dependents becomes rapidly worse. Almost without exception, when fertility rates drop below the replacement level economies have stagnated. Witness Japan and most European countries after about 1990. The U.S. and China will soon face those same demographic problems, and Latin America is only a few decades away.
Some Components of Population Pressure
If population pressure is the prime driver in human cultural evolution we need to focus on what causes population pressure to increase in one area rather than another. Certainly one obvious component of population pressure is the ‘circumscribed area’ factor. When a fertile region is circumscribed by desert or mountains population pressure on resources can occur rapidly. Thus, we see agriculture evolving first in river valleys surrounded by desert in the Near East and Egypt, and in highland basins surrounded by mountains in Middle and South America. The extensive plains of North America, Europe, and Asia, would presumably be far more suitable for agriculture, but very few cultigens evolved in these regions, and agriculture arrived very late—brought by persons migrating from more densely settled circumscribed regions where agriculture evolved. It appears that in those regions where people could simply expand their settlement area they were less likely to experience the sort of population pressure required to force major changes in lifestyle. Once again the direction of causation is reversed. Rather than agriculture evolving in those regions where environmental factors favored that development, it evolved almost everywhere in circumscribed areas, where population pressure forced people to intensify their production systems.
Another source of population pressure results from the migration of humans into areas where they were previously absent—the exotic species factor. Agriculture evolved in Middle and South America a mere few thousand years after humans first arrived; that same process occurred much more slowly in the Old World. Absent natural enemies population growth in the Americas would have been much higher than in the Old World. Humans arrived in America as big game hunters, and taking their prey and predators by surprise, were able to quickly dominate both. The mastodon, mammoth, rhinoceros, and hundreds of other (mostly large) animals were quickly driven to extinction in America by early hunters. Indeed, extinction of large animals was coincident with the arrival of humans throughout the world, and survival of such animals was mostly limited to those areas of the Old World tropics where human predation began much early with very primitive weapons, giving animals the necessary time to adopt fear of humans and defensive behavior. The rate of population growth in the Americas was many times greater than that of the Old World; indeed, in approximately the same time required for humans to move from southern to northern Scandinavia, humans moved from northern Alaska to the tip of Tierra del Fuego in South America. We must consider the facts that in contrast to the move north in Scandinavia, people were moving into a far more suitable environment in the Americas, that people in America had very little disease (having passed through that Arctic decontamination region where tropical diseases cannot exist), and that animals in America had no understanding of, and therefore no defense against, the human hunter.
Population Theory and Human Cultural Evolution
"There are two kinds of creatures in the world, fat things and thin things. Fat things are controlled by some other scarce resource, like nest sites or position in the group, while thin things are controlled by the food supply." Kenneth Boulding (Economist)
Thomas Malthus obviously believed humans are ‘thin things’, that is a creature with population growth controlled by the food supply; indeed, he did not seem to be aware of species that have limits on their population other than the food supply. Certainly, most large mammals appear to be primarily ‘thin things.’ That is, when the food supply is ample they appear to reproduce near the biological maximum rate. Even in the cases of those species that are controlled directly by predation, one can argue that it is food scarcity caused by overpopulation that increases their vulnerability to the predator. Consider the caribou and wolf population cycles in the sub-arctic of North America. When the wolf population is low, the caribou population expands rapidly; as the caribou population peaks near the maximum carrying capacity, the wolf population begins to expand rapidly. The consequent collapse of the caribou population resulting from wolf predation produces a subsequent collapse in the wolf population, followed by a renewed expansion of the caribou, and thereafter, the wolf population. Whereas the direct cause for the rapid decline in the caribou population is wolf predation, it can be argued that it is weakness induced by food scarcity that actually makes the caribou easy prey for wolves, and the absence of easy prey that causes the wolf population to decline rapidly.
Are humans ‘thin things?’ Do they reproduce as rapidly as possible when sufficient food is available? Or, are humans ‘fat things’; do they have some instinctive or cultural mechanism that limits their population growth below the maximum carrying capacity? Obviously, people now do maintain their population well below the carrying capacity. Did they always have that ability and inclination? If so, why didn’t we remain vegetarian primates confined to the hot wet tropics of Africa? The Boserup Theory suggests that some human groups did overpopulate their resource base and found it necessary to make some changes.
Could the Direction Of Causation Have Been Otherwise?
Does it make sense to suppose people living in the hot-wet tropics invented the weapons they would need to live in tropical grasslands before they moved there? Absent those weapons, would they have moved there voluntarily? Would people in the tropics have made clothing, shelter, and weapons needed to live in seasonally cold regions before they moved there and experienced the need for those innovations? Or, would some people have been pushed to the margins of the hot-wet environment, by population pressure, where they adopted survival technology and techniques? Would those pushed out of the home environment have been the more inventive and resourceful; or would they have been those least able to compete for space and food in the home environment? Did corn, wheat, beans, and all the other domestic cultigens (that have evolved a symbiosis with humans) exist prior to agriculture, so that a hunter could ‘discover’ them? Even if those food crops had been available (as they are to most hunter-gatherers groups today) would a hunter voluntarily decide to settle down and live with the weeds, rats, lice, and roaches, so he could be a farmer who works all day to provide himself with a very poor diet? Doesn’t it make more sense to believe population pressure reduced the amount of space per family to the point that it was impossible for people to sustain themselves by hunting and gathering, and that intensive gathering of plants produced the symbiotic interdependency between plants and humans that we call agriculture? Would 18th and 19th Century farmers have voluntarily moved to cities where sewage ran open in ditches in front of the hovels that served as dwellings, and where children worked 10 to 14 hours per day for starvation wages? In fact, the first English cities were filled with peasants who were pushed off the land by the Enclosure Movement, and U.S. cities were filled with emigrants from Europe who faced starvation if they remained in Europe.
What, other than necessity, could have motivated people to make any of those major changes, and what other than population growth could have made those changes necessary? From the perspective of the Boserup Theory, people were dragged kicking and screaming into each more advanced stage of civilization where they faced an immediate deterioration in their life style. If this is true, then it would appear that only population growth beyond the support capacity of the previous production system could explain why people made the change. Higher population densities produced diminishing returns to labor that resulted in an immediate deterioration in people’s lifestyle. Higher densities provided the incentive for each of the major changes in the relationship between humans and their habitat.
People are forced to offset diminishing returns to labor by working longer. Thus, farmers had to work more than hunter-gatherers and their reward was a poorer diet and more disease. Early industrial workers in 18th and 19th Century cities worked even more and faced a life expectancy 10 years less than farmers. Only recently has energy from fossil fuels allowed for a decrease in the workweek. Likewise, it is only recently that diets for most people improved and life expectancies extended, and only recently that life expectancies in cities became equal to or higher than those in the countryside. In low-income countries today, most young people who move to cities do so voluntarily because they expect to have a better and richer life in the city than they would have had in the countryside. That is a very positive change from urbanization in Europe and America where life expectancies were much lower than in the countryside, and where cities could only be filled with people forced off the land. Nevertheless, the people of low-income countries are paying a high price for development. Industrial production destroys the livelihood of many artisans and craftsmen. Some of those persons may be able to retrain for better jobs in new industries; but most have little chance for a new job and are pushed aside and forgotten. Often traditional cultural values are incompatible with development. Young people often understand this quickly, and discard the beliefs and values their parents hope to pass to them. The result is an older population that is insulted and depressed and a younger population frustrated by a loss of traditional values before a suitable replacement can be identified.
If it is true that there is no wind so ill that it does not blow someone good, the inverse is also true. Economic development is the only hope of well-being for the people of low-income countries around the world. But economic development will produce dislocation, loss of livelihood, loss of tradition, shortage, exploitation, and for some, starvation and death. Those horrors must be weighed against the alternative: Retaining the Traditional Society. Traditional society cannot provide the goods and services that people everywhere now hold dear, and to retain that system is to risk becoming a curiosity for tourists and anthropologists, an endangered people with little hope of making a cultural contribution to the future of the species.
If the Boserup Theory is correct, then a substantial amount of rewriting of human cultural evolution is in order. In addition, the vast increase in human populations over the past half-century in less developed countries takes on a very different perspective. Consider this: “We have seen the capacity of the earth expand, and seen population growth help to expand it, at each stage of economic evolution, from the hunting and food-gathering to the subsistence-agriculture regime, and thence to the regime of commercial agriculture and the industrial regime. There may be at least one more step in this evolution, and when that step has been taken, it may appear that the massive growth of population in our times was necessary for it.”
It is sometimes suggested that the Boserup Theory holds that population growth has always, and will continue to, result in sufficient innovation and technology to offset diminishing returns to labor. On the contrary, the Boserup Theory holds that population growth has generally not resulted in sufficient innovation to offset diminishing returns to labor! Throughout most of history humans have been hunter-gatherers; as such, they would have reached carrying capacity very quickly and thereafter experienced little if any population growth. We must assume that either continual starvation kept populations in check, or people evolved some sort of homeostatic cultural trait that reduced fertility. Anthropological studies of hunter-gatherers suggest the latter explanation is more plausible. Hottentots in southeast Africa were migratory, moving considerable distances every few months when game became scarce; their culture required women to carry all their children under age four. Having two children under the age of four was an almost certain death warrant for the mother. Obviously, high infant and maternal mortality would also have a major effect on reducing fertility. When hunter-gatherers invade territory where people were previously absent—as they did with the initial invasion of Europe and Asia, and later Australia and the Americas—they take prey by surprise and experience an initial period of rapid population growth. It is estimated that humans spread from what is now Alaska to the southern South America in just a couple of thousand years. Along the way they drove 200 genera of animals (mostly large mammals) to extinction, and quickly reduced the carrying capacity for hunter-gatherer peoples. Agriculture evolved very quickly in the Americas—only some 5,000 years or so after people arrived as hunter-gatherers. It is also significant that cannibalism was widely practiced throughout the Americas and in other regions where people invaded as exotic species. It is a simple fact that exotic species tend to overpopulate their habitat; when that happens they may become an important food source for those able to acquire that food source.
Are the Malthusian and Boserup Theories Relevant Today?
The Malthus and Boserup Theories can be interpreted in the broader context of supply versus demand as the cause for economic growth. Today, population growth is just one source of new demand, but population growth does compound other sources of increase in demand. A rate of economic growth that does not exceed the rate of population growth is by definition a development failure; economic development requires per capita levels of production to increase which means growth in production must exceed that of the population. The Malthusian Theory can be thought of as a supply-side view of development; that is, development can occur only to the degree that people are able (with new technology and working harder) to increase production faster than new demand. Malthusianists often refer to this relationship as the race between population growth and food production (or production generally).
On the other hand, the Boserup Theory can be viewed as a demand-side process where economic development may occur when real demand in the marketplace provides the incentive for producers to increase the production of goods and services they are able and willing to supply. The more important source of demand is raising expectations of people who feel they need more goods and services that were previously luxuries or unknown, compounded by population growth.
Do we have an economic downturn because the supply of goods and services is inadequate, and because we cannot increase production fast enough to keep up with demand? Or, is economic downturn caused by faltering demand for goods and services that we could easily produce if demand for them existed? We are pretty sure that in technologically advanced countries the problems are on the demand side. When the economy turns down we try to stimulate demand by cutting interest rates and taxes and by increasing government consumption of goods and services.
How about low-income countries? Is the economy of Ghana limited by the inability of the people to increase production of goods and services for which there is real demand in the marketplace? If so, they need to stimulate production by adopting new technologies and modernizing their farms and factories. If the supply of food can be increased by introducing modern farming systems, the problems of hunger and malnutrition can be addressed. Likewise, if modern factories and business practices are introduced, then the supply of goods and services can be increased. Thus, development initiatives should focus on the introduction of new technology and new methods to solve the problems of limited supply. That assumption drives most development strategies in low-income countries today.
However, if the economy is limited by the absence of demand (real demand backed by money) for goods and services that people could easily produce if they had an incentive, then trying to increase production will have little stimulating effect for the economy. Rather, Ghana should use the power of government to stimulate demand, just as we do in the technologically advanced countries.
Over the past 40 years I have interviewed a very large number of farmers in various countries of Latin America. One question at the top of my list is why the farmer does not increase production: Why not clear a bit more land and plant an additional quarter-hectare of corn? Why not apply a bit more fertilizer to that field so you can use it every year, instead of leaving it fallow every other year? Why not plant alfalfa in that field rather than making use of it for natural pasture? I have never met one farmer who responded that he did not know how, or was not able, to increase production. Rather, they have all responded: There is no market for the additional production; or, there is no way to get the additional production to the market; or, the owner of the truck going to the market town will charge me more than I will get for the product; or, most commonly, the government has set the market price below my production cost. Most factories in poor countries operate far below capacity, and would be more than happy to increase production. The capital goods used in factories are mostly produced in technologically advanced countries where the size of the market is very large. Because most poor countries have much smaller markets (lower incomes and often smaller populations) many machines in factories operate well below capacity. Even in those cases in which a factory is operating at capacity, owners would love to expand their operations with new buildings, capital goods, and workers, if they had a market for the products. They do not increase production because there is no market demand for the products they are willing and able to produce. I have never met a shoe-shine boy who was unable or unwilling to shine more shoes; never met a street vendor who was unable or unwilling to sell more goods; never met a taxi driver who was unable or unwilling to haul more passengers; and so on for every sector in the economies of Latin American countries. The problem is not inability to produce; rather, the problem is the absence of someone to buy the product. How can development be promoted by policies that aim at doing what people are already willing and able to do—increase production—rather than doing what people cannot do—increase real demand?
Hungry people with no money do not create demand for food. Likewise, people with no money do not stimulate demand for the goods and services produced in the non-farm sector. Hungry people with no money is NOT a food problem; that is a money problem! Likewise, when people with no money lack housing, clothing, and most other goods and services, the problem is NOT scarcity of housing, clothing, etc. Increasing the supply of food and other goods and services will not cause people with no money to purchase those commodities. Lack of money is caused by low salaries and wages, unemployment and under-employment, or by disability resulting from age or physical/mental conditions. Those problems can only be solved by increasing salaries and wages, providing employment for able-bodied persons and providing charity for those who cannot work because they are destitute children, elderly, or physically or mentally disabled. Often enterprise is slowed or prevented by misguided government bureaucracies that make it difficult or impossible to establish a new business, and by government attempts to set the prices of commodities below the cost of production. In Latin America many business activities are ‘informal’, that is unlicensed and unregulated. In many countries the informal sector of the economy is often the most productive and competitive. Indeed, if the informal economy did not exist, levels of unemployment and poverty would be many times higher. The best thing governments in poor countries can do to stimulate economic development is get out of the way! As Brazilians say: Our economy grows at night when the government is asleep.
Over the longer term, and especially in the later stages of development, increasing salaries and wages will depend upon increasing productivity with improved technology and labor-saving capital. In addition, improved technology may result in lower cost production and thus lower prices that can have a stimulating effect on demand. But, the first step toward increasing demand is being sure all able-bodied persons have access to employment. Modern technology is mostly labor-saving, and will tend to reduce the number of jobs in traditional sectors. Often the capital goods available to poor countries are already overly focused on labor-saving technology. Until poor countries are able to fully employ those people who want jobs, labor-saving technology is not likely to be appropriate technology.
We must also remember that there is no demand for a commodity until the existence of that commodity becomes known to potential consumers. In rich countries, advertising is an essential ingredient in stimulating demand; advertising causes people to want things that they would otherwise have been content to live without. In poor countries, the demonstration effect (becoming aware of a desirable item by seeing it used by another person) as well as advertising plays that role. It does not matter (for economic growth) whether the things people are convinced to want are actually worthwhile (in the judgment of outside observers). It only matters that people want them enough to increase their production sufficiently to get money to pay for them.
It is often suggested that sale of goods and services that are judged to be of trivial value should be curtailed, so that consumers would spend their money on goods and services that are ‘worthwhile.’ This view is very questionable. Unless the consumer who spends money on things judged to be of trivial value can be induced to start “wanting” those goods judged to be ‘useful’ (even though their actions suggest otherwise) total market demand will tend to decrease in direct proportion to curtailed demand for “trivial” items, causing the economy to shrink. (Restrictions on the consumption of harmful and addictive substances and services are justifiable for health and safety, rather than economic reasons.)
Political and Emotional Perspectives
The Malthus and Boserup Theories provide alternative interpretations of the human condition from a political and emotional perspective. The Malthusian Theory is a pessimistic view of the human condition. Some people may be inclined toward that theory because they see humans as a scourge or blight on an otherwise beautiful natural world. From this viewpoint, the Malthusian Theory should be correct because it will stop or reverse human population growth while there is still hope to save the natural world. The Boserup theory is a more optimistic view of the human condition. It suggests that people can and often have responded positively to the challenge of population growth by expanding production hundreds of times that possible under conditions of low population density. Some people may be inclined toward the Boserup Theory because they hope it is true or because they prefer to have a more optimistic outlook on life.
However, at issue here is not what we want to be true, but what we think is true! Which of these two theories best explains human cultural evolution, and which provides the more valid framework for economic development of low-income countries today? In order to make a rational judgment on which of these theories is true (or is more true, or is true more often, or true in a particular country, etc.) we must first understand both theories. Without a clear understanding of the Malthusian Theory and the Boserup Theory, one has no basis for making a judgment regarding either!
The Malthusian and Boserup Theories provide us with startlingly different viewpoints on the human condition. Both attempt to explain the parallel course through history of population growth and human caused increase in production. These theories differ on which of those two variables is cause and which is effect, and that makes all the difference!
Next Stage of Human Cultural evolution and Who Will Achieve It?
Will there be one more stage in human cultural evolution? That is, will there be a massive transformation in the way humans obtain their livelihood, accompanied by a massive increase in the population (or income)? If so, who will achieve that new revolution? It seems unlikely that humans could again experience high birth rates and greatly increase the population. On the other hand, population growth has become a small component of total demand.
Any significant change in the human economy would appear to be related to our energy source. So, what comes after fossil fuels? I don’t know; but I can guess who will discover it—whoever runs out of petroleum first. That won’t be Islamics, given that they are loaded with petroleum. And it won’t be the U.S. given the oil and gas strikes in the Dakotas and the Mid-West. Will it be Japan; they have almost no petroleum and little coal? Against that is a fertility rate in Japan well below replacement level. Of course European people around the world now have fertility below replacement level. European peoples have attempted to offset population decline with massive immigration from poor countries. In Europe most immigrants are Islamic people; in the U.S. they are Hispanics. In both cases, however, immigrants face severe discrimination. Anyone who thinks these immigrants are going to provide retirement and health care for an elderly population that imported them as cheap labor just hasn’t thought about it very much. Of course, Japan cannot employ that short-term solution, given that their culture cannot accept outsiders as Japanese. From the Boserup perspective, a declining population and declining demand (for other than health care) removes the motive and stimulus for innovation. On the other hand, who in 1650 could have guessed that England would become the first industrial nation and take over the world?
A Word of Caution
We have no definitive proof that either the Malthus or Boserup Theories are correct or incorrect. Both theories recognize the positive relationship between population growth and growth of the food supply. Of necessity, the two variables are positively correlated over the long term. A population cannot grow unless the food supply expands, and there is no reason to expand the food supply unless there is an increase in the number of consumers. A strong positive correlation between X and Y suggests a causal relationship between them. But, we cannot say whether X is the cause for Y or the other way about; nor can we be sure that both X and Y are not caused by some third factor. In order to establish one variable as a cause and the other as the effect, we must find a logical causal linkage between the two.
By way of analogy, undersea earthquakes are correlated with tsunamis (misnamed tidal waves in the U.S.). We see no way a tsunami could produce an earthquake, nor can we postulate some third factor as the cause for both earthquakes and tsunamis. On the other hand, causal relationship between an undersea earthquake and a tsunami is obvious (even if not completely understood). When an undersea earthquake occurs we issue tsunami warnings to coastal areas (although in many cases the tsunami does not occur). When a tsunami occurs without a recorded undersea earthquake, we assume that an undersea landslide or earthquake went undetected. Consider another case: During the polio epidemic in the 1950’s researchers found a strong positive correlation between the risk of polio and the percentage of surface area covered by concrete and asphalt. There seems to be no possibility that concrete could cause polio, nor could polio cause concrete. Nevertheless, the positive correlation does strongly suggest a causal link between the two variables. In this case, the percentage of the ground surface covered by concrete and asphalt is a very good proxy for human population density, and the relationship between a contagious disease and density is obvious.
The logic that Malthus used to establish food production as the cause for population growth has not proven to be true. We know that many people reduce their reproduction rate to replacement level even though they could easily support many children; and we know that in many places around the world people have maintained a high rate of growth in food and other production over the past couple of hundred years. Nevertheless, it is possible that some human groups did, or do, reproduce at a very high rate until they run out of food, and we cannot be sure the high rate of increase in the rate of production can be continued into the future. It has been suggested that medieval Europe faced a Malthusian Trap in which inability to increase the food supply limited population growth, and that the same could be true in some low-income countries today. In addition, there may be some other causal link between the food supply and population growth that would make the former the independent variable upon which the latter depends. For example, it is suggested that the production systems that have allowed the food supply to increase rapidly cannot be altered in a manner that would make them sustainable in the future, and that human population growth causes irreparable damage to the environment. If this is true, then food production may decline in the future and Malthus’ positive checks will stop and reverse population growth.
The logic Boserup used to posit population growth as the cause of increased food production seems compelling. Population growth would certainly encourage people to work their land more intensively, and if they fail to do so population growth could not be sustained. Given the fact that a more intensive land use system will produce diminishing returns to labor, it is difficult to understand how someone would accept the penalty of having to work more without the demand produced by population growth. Likewise, it is easy to see how high population densities provide increased opportunities for specialization and division of labor, and how literacy and formal education have tended to evolve in human societies only under conditions of relatively high density.
However, we cannot be sure population growth will always promote a more productive system, nor can we be sure that the pace of innovation will always keep production equal to or ahead of population growth. Boserup noted that when people respond to population growth with land use intensification without innovation the result is an involuted agricultural system, such as in parts of Asia, where men, women and children work long hours to produce just enough rice to keep themselves alive.
Boserup also takes issue with the view that intensive land use systems will necessarily be more destructive to the environment (in terms of the future carrying capacity for humans). She observes that more intensive land use systems tended to improve the production capacity of the land for human food. The most productive land on earth is in the densely settled regions of Europe and Asia where the natural fertility of the land was relatively low. The gray-brown podzolic soils of Western Europe, akin to those of northeastern U.S., are not very fertile under natural conditions, but they have been made the most fertile soils on earth with composting and fertilizing, and careful use. Likewise, tropical soils of much of South and Southeast Asia would not be suitable for multi-cropping were it not for the development of the paddy system in which nutrients are taken from the water rather than the soil. Boserup argues therefore, that soil fertility, and by extension the capacity of the earth to support humans, is mostly human-made.
Human exploitation of the world’s oceans, lakes and rivers remains today mostly in the hunting and gathering stage. In those few regions where aquaculture has replaced gathering of wild species, the production of fish and sea food has increased far beyond that possible under natural conditions. Most of the trout consumed in the U.S. is produced on a few dozen acres of land near the Snake River in Idaho. If there is a limit on the amount of trout that can be produced, it is not apparent to the people who run that facility. Indeed, production has been cut back recently because of competition by cheaper producers in Chile. Fish farming may hold a potential for expanding food production akin to replacement of wild plants and animals with domestic varieties on land.
In sharp contrast, many environmentalists argue that human use of the land is detrimental to the long-term sustainability of our production system. They warn that our soils are eroding away and forests are being depleted. Burning fossil fuels, on which our industrial system currently depends, adds carbon dioxide to the atmosphere that may lead to global warming with devastating consequences around the world. Some view the promise of fish farming with horror, predicting that replacement of wild species with domestic varieties will devastate the world’s oceans and lakes.
But then, what would early primates in the hot-wet tropics of Africa have thought about consumption of meat, or migrating to the seasonally dry tropics or the seasonally cold latitudes? And what would hunter-gatherers have thought about settling down with the weeds and their animal equivalents to become farmers? And what would farmers have thought about moving to cities where sewage ran open in the streets? I do not hold that the human future is secure as we move to this next stage of cultural evolution. But, I doubt that any concerns based on our current lifestyle could be relevant to that issue.
 It might be assumed by some that animals would have an instinctive fear of human hunters; however, anyone who has visited the Galapagos Islands or any other region where humans have been mostly absent, knows that animals that do not know humans do not fear humans. Early hunters in the new world used thrusting spears (far too large for a single man to throw) to kill the mammoth—that is three or four men walked under the animal and (on the count of three) thrust that spear into the mammoth’s heart (and then ran out before it collapsed on top). The mammoth would have had no more fear of a human than of a deer or rodent. That explains why 200 genera of mostly large mammals were driven to extinction in America during the first couple of thousand years after humans arrived. Notice that deer are not able to ‘defend’ themselves against cars. It’s really quite simple: only the front end bits, and only if you are on that pavement. But, the deer still haven’t figured that out!
 Japan enjoyed the same geographic relationship with China, and experienced similar advantages. Note that Cuba also had that geographic relationship with the Aztec Empire, but the Spanish invasion precluded exploitation of their location.
 Early industrial cities in the U.S. were mostly filled with European immigrants who faced starvation in Europe.
 The transition from high birth and death rates to low birth and death rates that began in the more technologically advanced and richer countries, and has now spread throughout most of the world.
 The exceptions include those diseases that evolved into the human body and were thus not eliminated by mid and high latitude environmental conditions. One such disease was syphilis, which began as a skin disease in Africa but evolved into the human body to be transmitted sexually. Venereal syphilis arrived in Europe a few years after Columbus’ voyage and spread through that continent with devastating results. Native Americans also had the stomach virus that we now call ‘Montezuma’s Revenge’; Spanish conquerors suffered from that malady, as you will if you if you travel to Latin America and fail to be very careful of what you eat and drink (and likely even if you are careful).
 J.D. Durand, “World Population: Trend and Prospects,” Population and World Politics, P.M. Hauser (ed), The Free Press, 1958.
 This is the first time any species of life on earth has voluntarily failed to reproduce. What could account for this incredible and disastrous turn of events? I have speculated that it is caused by the ‘Green Religion’—that is the belief that humans are unnatural and are destroying an otherwise beautiful natural world, and alternatively, that cradle-to-the-grave socialism has removed in important incentive for reproduction (note that fertility below replacement level began in communist countries). Notice that most people are not even aware of this looming disaster and there is almost no mention of it in the media.
 Even second and third generation Koreans who are indistinguishable from Japanese and who speak the language as natives carried the same ‘outside person’ card that I carried while living in Japan.