고령화에 의한 인구증가와 경제성장의 장기적 메커니즘

Abstract

This paper presents a mechanism that explains the impact of increased longevity on population and economic growth, as well as its implications. The mechanism is based on the three building block mechanisms such as quantity-quality choice of kids, an endogenous growth mechanism, and a segregated labor market for old agents. The model economy is a three period OLG, open, and perfectly competitive economy. In period 0, agents invest a certain fraction of one unit of endowed time in education, work for the rest, save and consume. In period 1, they use a certain fraction of another endowed one unit of time for child rearing, the rest of the time for work, save and consume. In their last period, they work for one unit of time with their experience capital, and consume. The interest rate is given at the inter- national equilibrium rate determined in the international financial market. And there exists a representative firm with the production technology with a CES between young and old labor. This model economy produces the following impli- cations. First, an increase in longevity lowers wage rates of old agents, relative to those of young ones, thus raising saving to maintain the consumption level in period 3. This leads to lowering the physical investment and child rearing time. This thus lowers the number of kids, population growth. Second, an increase in longevity is moderate, investment in human capital increases as a means of saving to compensate for the lowered old workers’ wage to maintain their consumption level, leading to higher economic growth. However, when the longevity increase is higher than a certain threshold level, investment in human capital decreases because its opportunity cost of sacrificing the period 0 consumption increases significantly. Third, several government policies have the following implications. An increase in old workers’ employment or in their labor efficiency lowers human capital investment and thus economic growth because it lowers their wage rates, while it increases population growth. In contrast, an expected increase in lump-sum subsidy raises both quality and quantity of kids, thus economic and population growth. It is because of its positive income effect on the quality and quantity of kids and on the old period consumption of raising human capital as a means of saving.