Wednesday

 Mostly summarized from Gregory Mankiw’s Principles of Economics, 5th Ed.

PART 9 The Real Economy in the Long Run
Chapter 25 of 36 Production and Growth
Section 20 of 21
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Things government can promote and strengthen to increase productivity and living standards include
1· saving and investment
2· investment from abroad
3· education
4· health and nutrition
5· property rights and political stability
6· free trade
7· research and development
8· population growth
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8· population growth, continued
The on-going debate over the effects of a growing world population includes these topics:
a· Stretching natural resources
b· Diluting the capital stock
c· Promoting technological progress
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c· Promoting technological progress.
Some economists contend world population growth has powered technological progress and economic prosperity.
If there are more people there are more scientists, inventors, and engineers to contribute to technological advance.
Economist Michael Kremer supported this hypothesis in his 1993 article "Population Growth and Technological Change: One Million B.C. to 1990."
Kremer begins by noting over the span of human history world technology growth rates have increased with world population.
This is consistent with the hypothesis a larger population induces more technological progress.
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Kremer's second part of evidence is from comparing regions of the world.
The melting of the polar icecaps at the end of the Ice Age around 10,000 B.C.
flooded continental land bridges and separated the world into several separate regions that for thousands of years could not communicate with one another.
If technological progress is more rapid when there are more people to discover and invent things then higher population regions where people can readily communicate should have had more rapid technological growth.
Kremer asserts that is what actually happened.
The most successful region of the world in 1500 was the "Old World" civilizations of the large and connected Eurasia-Africa region.
Next in technological development were the Aztec and Mayan civilizations of the Americas, followed by the hunter-gatherers of Australia, followed by the primitive people of Tasmania.
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The smallest isolated region studied was tiny Flinders Island between Tasmania and Australia.
It had a small population that seemed to actually regress technologically.
Around 3000 B.C. human society completely died out on the island.
Kremer concludes a large and communicating population is necessary for technological advance.
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ChatGPT summary of article Population Growth and Technological Change: One Million B.C. to 1990” (1993) by Michael Kremer.
This is a highly influential paper that rethinks the long-run relationship between population and economic progress.
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Core Idea
Kremer argues population size itself is a key driver of technological progress.
Because ideas are nonrival (one person’s use doesn’t reduce others’ ability to use them), more people means more potential inventors.
This creates a feedback loop:
larger populations →
more innovation →
higher carrying capacity →
larger populations
Over most of human history, this dynamic produced accelerating population growth rather than stagnation.
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The Model
Kremer combines two major frameworks:
-Malthusian constraint: population is limited by available technology for food and resources.
-Endogenous growth theory: technological change depends on human activity and the number of people.
The key prediction is population growth rates rise with population size, because more people generate more ideas.
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Historical Evidence
Using data spanning from 1,000,000 B.C. to 1990, Kremer shows:
-Population growth was extremely slow early on, then gradually accelerated.
-Over long periods, growth rates roughly track population size.
-Regions with larger initial populations developed technology faster.
He also uses a natural experiment: after rising sea levels isolated continents around 10,000 B.C., Eurasia —being the largest population center— experienced the fastest technological progress, while smaller, isolated populations advanced more slowly.
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Key Implications
-More people → more ideas→ more people
Population growth can be a source of innovation, not just a strain on resources.
-Long-run growth is self-reinforcing
Technology raises population capacity, and population accelerates technology.
-Explains accelerating history
The model helps explain why human progress appears to speed up over time.
-Limits of the model in modern era
In the 20th century, population growth slows despite rising technology and income — suggesting additional factors including education, and fertility choices, now dominate.
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Bottom Line
Kremer’s paper overturns the purely pessimistic Malthusian view by showing population growth and technological progress are mutually reinforcing forces over most of human history.
The long-run pattern is not simple scarcity — but a powerful feedback loop between human numbers and human ingenuity.
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the island’s technology level seemed to regress
shima no gijutsu suijun wa koutai shite ita youda
島の技術水準は後退していたようだ