The Discovery of Agriculture
By Rochelle Forrester
© All Rights Reserved
Published in 2002
The
domestication of plants and animals has been a much discussed event in
prehistory and anthropology. It has however been much troubled by a lack of any
firm knowledge of how the process took place. Most attention has focused on
trying to identify when, where and in what circumstances agriculture first
emerged. Why agriculture emerged has usually been explained by its offering
significant economic advantages to human populations over that which would be
provided by the hunting and gathering lifestyle. This has been called into
question by recent studies of modern hunter-gatherers which suggest
hunter-gathering may be a better lifestyle than previously imagined. However if
this is true and if it is possible to use studies of modern hunter-gatherers to
assess the living conditions of hunter-gatherers before the agricultural
revolution, then it is necessary to explain why humans took to agriculture and
why they did it when they did.
A
further point that needs to be explained is why most of humanity took to
agriculture at the same time. Anatomically modern humans, homo sapiens sapiens,
have been around for at least 50,000 years and for approximately 40,000 or more
of those years they obtained their food by hunting and gathering. Then, within
a period of about 8,000 years, the great majority of humanity were making their
living by farming. Why such a long wait, followed by the spread of agriculture
across a large part of the land inhabited by humans? Obviously diffusion of
agricultural knowledge is an explanation for its rapid spread in this 8,000
year period, but it seems clear that agriculture was independently invented in
a number of areas and most certainly in the new world.
Various
explanations have been put forward for the development of agriculture. One
involves plant mutations such as mutant maize, but such mutations would have
been available many times before agriculture was developed, but were ignored.
When agriculture developed, a wide variety of different crops were
domesticated, and it is hardly likely that they all developed convenient
mutations at approximately the same time without those mutations occurring many
times previously. We need to explain why the human population took advantage of
the mutations, if that was how agriculture developed, when they did and why
they had previously ignored the mutations.
Another
explanation is that the right conditions for agriculture developed due to
climate change that preceded the development of agriculture. However this
explanation has the problem that many different climates would have existed on
earth during the 40,000 or more years that homo sapiens sapiens inhabited the
earth before the development of agriculture. Many of these climates would have
been just as suitable for the development of agriculture as the climates in
which agriculture eventually developed. Yet agriculture did not develop until
some 10,000 years ago despite the presence of suitable climates for the
development of agriculture in the preceding 40,000 or more years of homo sapien
sapiens occupation of the planet.
An
alternative explanation for the development of agriculture is that it was
forced by population pressure. The problem with this view is that it does not
explain how humans learnt to engage in agriculture and why there was population
pressure at that particular time 10,000 years ago but not at other times in human
prehistory. The human population through most of this time was able to expand
into new lands, such as America, but the populations in Africa, Europe and the
Middle East were not able to expand into new lands in the way that the North
East Asian population was able to expand, so they may have been under
population pressure many times in the period before agriculture began. Local
population pressures would have developed many times in prehistory but did not
give rise to the development of agriculture. Before humans began to move into
America and Australia, they had for several hundreds of thousands of years
occupied all of Africa, Europe and Asia and despite population pressure, never
developed agriculture. The population theory says that agriculture developed in
the Middle East because humankind ran out of room to expand in South America,
as though the people of the Middle East felt population pressure 10,000 years
ago due to humankind running out of room to expand in South America. It is
hardly likely the people of the Middle East would have felt population pressure
due to events in South America. In the modern world, with its advanced
transport and communications, some countries such as Japan are arguably over
populated yet it does not have much effect on other countries. It would seem
likely due to excessive migration into fertile areas, or due to once fertile
areas becoming less fertile, there would be excessive population pressure on
the land at many times in prehistory, but there is no evidence that this ever
lead to the development of agriculture.
Many
of the proposed explanations for the development of agriculture have the common
defect of not being able to explain why agriculture developed when it did, and
not before, as the proposed explanations involve conditions which almost
certainly existed many times before agriculture was actually developed. The
only plausible explanations for the development of agriculture are those that
are able to answer the question of why agriculture did not develop before 10,000
year ago.
One
explanation that does not suffer from this problem is that suggested by L H
Morgan (1877) and V Gordon Childe (1955) and others that agriculture developed
as part of a natural process of cultural evolution when a certain level of
knowledge and technology had developed. This view has been much criticized in
the last twenty or thirty years due to research into modern hunter-gatherer
societies. This research suggests that the knowledge that plants grow from
seeds was available to hunter-gatherers in prehistory. (Cohen, 1977, 19).
Evidence cited in support of this position is that modern hunter-gatherers
understand agriculture and that hunter-gatherers must inevitably have a
considerable knowledge of the plants and animals they live off. It is claimed
there is no significant difference between the knowledge hunter-gatherers have
of the plants and animals they needed for their survival and the knowledge of
plants and animals required for agriculture and domestication. (Cohen, 1977,
20-23). There is a problem with this as obviously modern hunter-gatherers could
and would have learnt plants are grown from seeds from 10,000 years of contact
with agrarian societies.
It
is quite difficult to find hunter-gather groups that have had no contact with agrarian
societies. Where there are such hunter-gatherers they do not seem to understand
that plants grow from seeds. The Australian Aborigines were quite familiar with
the seeds of various grasses, but they seemed to be unaware that the grasses
and other plants grow from seeds. (Elkin, 1974, 51). An analogous situation
between seeds and plants is between sex and giving birth. The Australian
Aborigines believed a woman became pregnant when a spirit being enters her body
and before contact with Indonesians and Europeans seemed to have little
understanding of the relationship between sex and pregnancy. (Abbie, 1970,
200-202). They do not seem to be alone in this, the Trobriand Islanders studied
by Malinowski seemed to be in the same position. If hunter-gatherers are unable
to work out the relationship between sex and giving birth, both matters they
were closely involved with; it seems unlikely they would understand the
relationship between seeds and plants, things which while they have some
familiarity with, they would not be as familiar with as they would be with sex
and child-birth.
A
similar situation exists with the belief from the time of the ancient Greeks to
the mid 19th century in the spontaneous generation of life forms from
non-living matter. Certain life forms such as maggots, bees, mice and others
were considered to arise spontaneously from other matter such as hay or
decaying plant or animal matter. Spontaneous generation was eventually only
disproved by experiments by Pasteur and the development of powerful microscopes
in the mid 19th century. If a literate society, well acquainted with the rules
of logic, continued to believe in spontaneous generation some hundreds of years
after the start of modern science, then it is very likely that prehistoric hunter-gatherers
would have been unlikely to work out that plants come from seeds. The most
probable and plausible belief for prehistoric hunter-gatherers as to the source
of plants, given their knowledge at the time, was spontaneous generation from
the earth. Alternatively, prehistoric hunter-gatherers may have believed plants
come from the gods or some other supernatural cause.
A
further point is that if it was true that the knowledge of agriculture and
domestication was known to hunter-gatherers before agriculture and
domestication became common, then one would expect to some find evidence of
agriculture and domestication long before 10,000 years ago. It is hardly likely
that the conditions (whatever they were) that lead to the development of
agriculture some 10,000 years ago, never occurred in the previous 40,000 or
more years homo sapiens sapiens has been on this planet. One would expect to
find evidence that where the conditions were right agriculture was practiced
and then if the conditions later turned against agriculture it would be
abandoned. Such evidence exists with "lost cities" in America and
Zimbabwe, but these cities were obviously built long after the discovery of
agriculture some 10,000 years ago. It seems clear that agriculture only developed
10,000 years ago and then by both diffusion and independent invention was
adopted by the great majority of human beings. This hardly supports the idea
that the knowledge required for agriculture was widely known amongst
hunter-gatherers prior to 10,000 years ago.
A
further problem for the idea that early hunter-gatherers had knowledge
sufficient for agriculture is that they could, to borrow a phrase from Thomas
Kuhn and The Structure of Scientific
Revolutions, be considered to be living in a different paradigm from the
people who practice agriculture. Hunter-gatherers are interested in where the
food is and how to get it. Farmers however are interested in how to make plants
grow. They need to know about the planting of seeds, the creation of clearings,
which plants grow best in which soils, the enrichment of soils and the watering
of their gardens, the importance of removing weeds, conservation measures such
as are involved with shifting agriculture and how plants can be improved by a
process of selection. These sorts of measures, necessary for successful
agriculture, will not be obvious to hunter-gatherers. Plants growing wild, the
only plants known to pre-agriculture hunter-gatherers grow without being in
specially cleared areas. Which soils plants grow best in is of no interest to
hunter-gatherers, they are looking for plants not soil types. That plants grow
better when the soil is enriched and weeds are removed would not be obvious to
hunter-gatherers. That nutrients in the soil get exhausted after a few crops
and it is necessary to plant additional crops at a new location, or to let the
land lie fallow, or to replace the nutrients, would not be obvious to
hunter-gatherers. Knowledge of these things could only be developed by trial
and error, not by simple observation of wild plants. It could only be developed
by the actual practice of agriculture. The most hunter-gatherers could learn
simply by observation would be that plants require water and that plants grow
well in areas cleared by fire. As much of what is needed for successful
agriculture can only be learnt by trial and error and not by the observation of
wild plants it seems that pre-agricultural hunter-gatherers could not have had
the knowledge required for agriculture. Present day hunter-gatherers may well
have that knowledge but it is obvious they could and would have learnt that
knowledge from contact with agrarian peoples over thousands of years. That of
course is one of the ways the diffusion of agriculture occurred. However when
the environment of the hunter-gatherers who had learnt of agriculture was
unsuitable for agriculture then the hunter-gatherer life style continued.
A
final problem for the idea that hunter-gatherers in prehistoric times knew
plants grow from seeds is that this idea is far from obvious. Seeds look quite
unlike plants, so there is no reason to believe they will eventually grow into
plants. There is also a significant time period before seeds turn into plants
so that it is not obvious the seeds will become plants. Finally, in many cases
seeds will not grow into plants, due to factors such as poor soils, a lack of
water or to many weeds.
A
similar situation exists with the domestication of animals. The earliest
domestic animals are believed to be dogs which were domesticated in South-West
Asia 12-14,000 years ago. Dogs would be useful assets to hunter-gatherers being
capable of acting both as guard dogs and also as playing a role in hunting as
they do today, for example when hunting pigs. Yet they were only domesticated
after 40,000 or more years of homo sapiens sapiens existence. It seems likely
the domestication of animals took so long because for a long period of modern
human existence they were simply unaware of the usefulness of dogs and other
domestic animals and of how to domesticate them. If prehistoric hunter-gathers
did know how to domesticate dogs, before 14,000 years ago, surely they would
have done so.
The
view that agriculture was adopted because it offered economic advantages in
comparison with hunter-gathering has been questioned recently. Studies of
modern hunter-gatherers have suggested they obtained ample calories and protein
and consume a wide variety of food. Their life styles are usually preferred to
those of farmers and they obtain their food supplies with less labor than is
required of farmers. Many studies suggest the hunter-gatherer lifestyle is
simply overall superior to that of farmers. (Sahlins, 1972).
There
are however problems with these studies. There are a limited number of them;
labor costs are measured in a variety of ways; how does one compare the costs
and benefits of sedentism; how does one assess the fact that farmers normally
produce a surplus and the costs of storage. Cohen suggests there is probably no
method of fairly comparing agriculture with hunter-gathering. (Cohen, 1977,
34). It has been suggested by Hill and Hurtado (1989, 436, 442) that the
results of studies of modern hunter-gatherers are so variable that no group
could be considered to be typical and could be used as an analogy for studying
our ancestors. Considerable attention has been directed towards the !Kung San
who seem to be an unusually prosperous group of hunter-gatherers.
There
is however a much greater problem. It is quite uncertain as to whether studies
of modern hunter-gatherers gives any real indication of what life was like for
prehistoric hunter-gatherers. Some suggest that as hunter-gatherers only occupy
marginal environments in recent times, while before the development of
agriculture they would have occupied better lands, they would have been better
of in earlier times. However whether a group is prosperous or not depends not
just on the fruitfulness of the land but also on the size of population on that
land. Poor quality land may support a small population in some affluence while
a larger population on better land may not live very well at all. The
prosperous !Kung San actually live in a desert but live well presumably due to
a low population density on the land.
It
is also suggested that the presence of agricultural people would interfere with
the ability of hunter-gatherers to move at will and so reduce their economic
opportunities and their standard of living. However it is not at all clear that
before agriculture hunter-gatherers were able to move at will. Hunter-gatherers
tend to have territories and to wander into another bands territory could
produce conflict. So it is not necessarily the case that hunter-gatherers in
prehistory could wander at will so whether their choices of movement were any
more restricted after the development of agriculture, than before is somewhat
doubtful.
A
more significant matter is that modern hunter-gatherers have a number of
benefits not available to prehistoric hunter-gatherers. The first is that
modern hunter-gatherers have access to goods and tools that prehistoric
hunter-gatherers did not have, due to trade with modern agrarian and industrial
societies. Most modern hunter-gatherers have access to iron, making hunting,
digging for food and cutting down trees considerably easier. Other products
such as pottery, rope and modern medicines might well make the lives of modern
hunter-gatherers more comfortable than their prehistoric counter parts. Some
modern hunter-gatherers actually hunt with shot guns. One effect of this is
that it is likely to give modern hunter-gatherers the edge when it comes to
confronting large carnivores. Prehistoric hunter-gatherers armed with flint,
bone or ivory tipped spears or arrows may not necessarily have been the top
predator in environments containing lions, tigers, leopards, bears, wolves and
other fast and well equipped predators. Bears were hunted by the Tlinguit
Indians of the north-west coast of America and men were sometimes killed in
these hunts. Nowadays the Tlinguit use powerful steel traps when hunting bears.
(Oberg, 1973, 67-68). Snake bites and attacks by jaguars represent a
significant proportion of deaths among the Ache in eastern Paraguay. (Hill
& Hurtado, 1989, American Scientist, 77(5) 442).
A
further benefit modern hunter-gatherers have over their predecessors is that of
a higher authority to control and keep order between them. In the event of a
dispute between two hunter-gatherer bands their is a much more powerful
authority, the government of whatever state the hunter-gatherers live in which
will usually prevent them from killing each other. There is no such authority
to enforce law and order for prehistoric hunter-gatherers. Disputes may end up
being settled by force to the benefit of the strongest or most numerous. Hill
& Hurtado note that among the Ache warfare and accidents account for 73% of
adult deaths. The equivalent figures for the Hiwi are 39% and for the !Kung-San
11%.
Yet
a further advantage modern hunter-gatherers have over their prehistoric
counterparts is that modern hunter-gatherers may well receive support in bad
years from modern governments. Climates vary and most areas will occasionally
suffer from drought which will cause the destruction of the plants and animals
hunter-gatherers live on. For prehistoric hunter-gatherers this would mean
famine unless they were able to move towards more fertile areas. This would not
be easy if the drought covered a large area and because prehistoric
hunter-gatherers would not necessarily know where the better areas are.
Migration to other areas may well involve conflict with other hunter-gatherer
bands. Modern hunter-gatherers may well be protected from such disasters but
such protection was not available to their prehistoric counterparts. The true
test of how people live is not their average or good years but how well they
survive in their bad years, as there is little value in having a number of good
or average years if they are followed by a single bad year that causes half the
band to die of starvation. In these circumstances it seems hardly likely that
studies of modern hunter-gatherers will give much idea as to how prehistoric
hunter-gatherers lived.
The
most convincing explanation of the development of agriculture is that by Robert
and Linda Braidwood. They emphasize cultural rather than environmental, plant
mutation or population explanations for the development of agriculture. All
those explanations have the problem that they cannot explain why agriculture
suddenly developed when it did after such a long period of hunter-gathering.
The Braidwoods argue that it was improvements in human technology and human
knowledge of the environment over time that lead to the development of
agriculture. (Price & Gebauer, 1995,25). (Braidwood, LS & RJ
Prehistoric Village Archaeology in South East Turkey, Oxford: British
Archaeological Reports S 138), (Braidwood RJ The Agricultural Revolution,
Scientific American, 203, 130-141). (Braidwood RJ Prehistoric Men, Glenview,
Illinois, Scott Foreman & Co). It is of course impossible to trace the
growth in human knowledge in prehistoric people but improvements in human
technology are to some extent traceable.
This
can be shown in a number of ways. Brian Fagan shows how over time stone tool
makers learnt how to make better and better use of a pound of flint to produce
successively greater volumes of cutting edge. (Fagan, 1995, 111). A similar
process can be seen in technological changes that occurred after about
30,000bp. These included improved techniques for the working of raw materials.
Before this time technology largely involved the use of only four techniques,
those of percussion, whittling, scraping and cutting all of which required only
a limited range of hand motion. After 30,000bp new techniques were added
including pressure flaking, drilling, twisting grinding and others, which
involved different motor abilities than those used previously. Secondly, in the
earlier period the main raw materials used were stone, wood and skin. Later on
bone, ivory and antler and less importantly shell and clay were added to the
original materials. Thirdly, the number of components in composite tools
expanded considerably after 30,000bp increasing the complexity of the tools
used. Fourthly, the number of stages involved in manufacturing artifacts significantly
increased after 30,000bp. Before 30,000bp manufacturing involved only a short
series of single stage operations, while later there were often several stages
of manufacture to produce the final product. The number of processes and
techniques had increased as had the degree of conceptualization required to
manufacture the product. (Dennell, 1983, 81-87).
In
the period between the middle and upper Paleolithic there were substantial
improvements in the artifacts available to people. Hunting equipment improved
by the use of narrow bone or ivory points for spears which had greater
penetrating power than earlier flint tipped spears. Spear throwers and the bow
and arrow were also introduced allowing prey to be killed from a greater
distance. Cooking was made more effective through the use of cobble-lined
hearths which allowed heat to be retained longer and at a more even
temperature. Improvements in clothing seem to have been made between the middle
and upper Paleolithic providing humans with much better protection against the
elements. Eyed needles seem to have been invented around this time. Housing
became more sophisticated in the upper Paleolithic with many structures being
made of mammoth bones suggesting that some sort of sophisticated transport device
such as sledges were used to move the bones. Art which played little role in
the middle Paleolithic, became much more extensive in the upper Paleolithic.
Cave paintings appeared in Europe, Australia and North and South Africa. Many
artifacts such as bone needles, ivory beads, spear throwers and bows had
engravings or carving performed on them. Artistic objects such as Venus
figurines were traded over considerable distances suggesting the upper
Paleolithic had much improved trade and communications than the middle
Paleolithic. (Dennett, 1983, 87-96). Technology developed by hunter-gatherers
in the Middle East, to utilize wild cereals, such as stone sickles and
underground storage pits were useful to early cereal farmers in the Middle
East.
The
substantial improvements in the tools, clothing, art and general culture of
humankind between the lower and upper Paleolithic could only have taken place
with a gradually increasing knowledge of how to make better and better use of
the materials in the environment. It seems likely that the increased knowledge
of the human environment shown by archaeological finds of tools, art and other
Paleolithic objects would have been matched by a gradually increasing knowledge
of the plants and animals humans live off. Hunter-gatherers are known to have a
very great knowledge of the plants and animals in their immediate environment,
but that does not mean they always had such knowledge. In particular knowledge
not directly related to the hunter-gatherers survival, such as how to make
plants grow and how to tame animals would not necessarily be immediately known
to hunter-gatherers and might only be learnt after a long period of gradually
increasing knowledge. As noted earlier, such knowledge was irrelevant to the
hunter-gatherer life style, and so may have taken some time to become part of
the culture of human-kind.
There
is very little in the way of hard facts known about the domestication of plants
and animals. Most theories as to how this came about contain a fair amount of
guess work. Nevertheless the best theory would seem to be that the knowledge
required for the domestication of plants and animals gradually increased over
time until enough was acquired to allow the domestications to take place.
Theories involving climate change, fortuitous mutations and population pressure
causing the domestications all have the problem that such factors would have
occurred many times before the agricultural and pastoral revolutions without
agriculture and pastrolism being introduced. This strongly suggests that before
the agricultural and pastoral revolutions human beings simply did not know how
to successfully grow plants and how to domesticate animals.
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Price, T. D. & Gebauer, A. B. (ed) (1995) Last Hunters-First Farmers, School of
American Research Press: Santa Fe, New Mexico
Dennell, R (1983) European Economic Prehistory, Academic Press: London
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