Abstract: This paper shows that the Malthusian mechanism alone cannot explain the pre-industrial stagnation of living standards. Improvement in luxury technolog

Abstract: This paper shows that the Malthusian mechanism alone cannot explain the pre-industrial stagnation of living standards. Improvement in luxury technology, if faster than improvement in subsistence technology, would have kept living standards growing. The Malthusian trap is essentially a puzzle of balanced growth between the luxury sector and the subsistence sector. The author argues that balanced growth is caused by group selection in the form of biased migration. It is proven that a tiny bit of bias in migration can suppress a strong growth tendency. The theory re-explains the Malthusian trap and the prosperity of ancient market economies such as Rome and Sung. It also suggests a new set of factors triggering modern economic growth.