James Kwak in The Washington Post:
Homo sapiens have big brains. We use those brains to develop new technologies, which enable us to produce more stuff and support larger populations on the same amount of land. Higher population density makes possible greater specialization and increases demand for innovation. As a result, cultural attributes that favor education and innovation become more valuable, so families with those attributes are more likely to reproduce, resulting in a population that is more favorable for further technological development.These “wheels of change” have been the key drivers of technological progress since the beginning of time, economist Oded Galor argues in his new book, “The Journey of Humanity: The Origins of Wealth and Inequality.” Throughout most of our history, however, our species was caught in a poverty trap. Technological innovation caused increases in food production, which caused higher population growth — until the additional mouths to feed canceled out the productivity gains, bringing living standards back to subsistence levels. In the 19th century, however, the inexorable march of technology reached a tipping point. With the Industrial Revolution, according to Galor, the value of human capital reached the point that parents chose to have fewer children and invest more in their upbringing. Longer life spans made human capital even more important. As women’s wages began to approach those earned by men, it became more costly for them to leave the workforce to have children, further reducing birthrates. This demographic transition allowed technological progress to vastly outstrip population growth, producing our present world of material plenty.
More here.