x About 5,000 years ago, it could be found in West Africa,
Mesoamerica, the Andes, Central Asia, and parts of Europe. By
then, most humans lived as small peasant farmers, and that way of
life would dominate the history of the next 5,000 years.x Within just 5,000 years, agriculture had become the dominant
technology of most human societies on Earth. This was a
revolutionary change in human history.Agriculture did not necessarily spread because it was attractive to foragers.
It spread, rather, because agricultural communities could generate more
resources than foraging communities and could therefore support larger
populations. Even the simplest farming communities could support 20–30
times as many people per square kilometer as most foraging communities. As
agriculture spread, world populations rose from about 6 million to 50 million
between 10,000 and 5,000 years ago. The population of Southwest Asia
alone may have increased from 100,000 to 5 million between 10,000 and
6,000 years ago (Bellwood, First Farmers, p. 15). This meant that, though
Agrarian and foraging societies often traded and lived together peacefully,
when there were conÀ icts, Agrarian societies had more people and more
resources than their foraging neighbors. This is why the Agrarian frontier
slowly advanced at the expense of foragers, as farmers began to cultivate
more and more regions with easily worked soils and adequate rainfall and
sunlight.
Agriculture introduced a new technological dynamism into human history
because it stimulated collective learning. How? With larger populations,
there were more people to exchange ideas within and between communities.
Population growth forced those at the margins of society to experiment with
new techniques and crops. Population growth generated conÀ icts over land
and resources, and warfare began to drive technological and social change in
new ways.
For the most part, technological change took the form of micro-innovations,
each adapted to particular environments. Two fundamental Agrarian
techniques in this era were horticulture and swidden agriculture, each of
which evolved with many local variations. “Horticulture” means farming