Long Trends—Rates of Innovation Lecture 34
One more example [of micro-innovations] may be the slow spread of windmills. We ¿rst get evidence of them in Persia late in the 1st millennium C.E. And then they start to spread quite widely throughout the Mediterranean, eventually in Europe.
B
y modern standards, change was slow in the era of Agrarian civilizations. So it is all too easy to think of this as an era of stagnation. Yet we have also seen that there was considerable long-term growth in this period, and that suggests that there must have been a continuous trickle of innovations. What factors encouraged innovation in the era of Agrarian civilizations? Earlier lectures argued that collective learning—the ability to share and accumulate learned information—is what makes our species different. Ultimately, collective learning is the source of all innovation in human history. Indeed, collective learning can generate cycles of positive feedback, as innovations allow population growth, which increases the number of people contributing to innovation. But speci¿c features in each era and region can also accelerate or slow the pace of innovation. This lecture discusses four features of Agrarian civilizations that could stimulate innovation. x
Population growth.
x
Expanding networks of exchange.
x
Increasing market activity.
x
The role of states.
Danish economist Ester Boserup (1910–1999) argued famously that population growth can stimulate innovation, as those at the edges of society are forced to seek new ways of feeding and supporting themselves. During the 4,000 years of the later Agrarian era, human populations multiplied by about ¿ve times, growing from about 50 million to about 250 million people. 155
