From Physical to Human Capital Accumulation: Inequality and the Process of Development

Abstract

This paper develops a growth theory that captures the replacement of physical capital accumulation by human capital accumulation as a prime engine of growth along the process of development. It argues that the positive impact of inequality on the growth process was reversed in this process. In early stages of the Industrial Revolution, when physical capital accumulation was the prime source of growth, inequality stimulated development by channelling resources towards individuals with a higher propensity to save. As human capital emerged as a growth engine, equality alleviated adverse effects of credit constraints on human capital accumulation, stimulating the growth process. This research develops a growth theory that captures the endogenous replacement of physical capital accumulation by human capital accumulation as a prime engine of economic growth in the transition from the Industrial Revolution to modern growth. The proposed theory offers a unified account for the effect of income inequality on the growth process during this transition. It argues that the replacement of physical capital accumulation by human capital accumulation as a prime engine of economic growth changed the qualitative impact of inequality on the process of development. In the early stages of the Industrial Revolution, when physical capital accumulation was the prime source of economic growth, inequality enhanced the process of development by channelling resources towards individuals whose marginal propensity to save is higher. In the later stages of the transition to modern growth, as human capital emerged as a prime engine of economic growth, equality alleviated the adverse effect of credit constraints on human capital accumulation and stimulated the growth process. The proposed theory unifies two fundamental approaches regarding the effect of income distribution on the process of development: the Classical approach and the Credit Market Imperfection approach. 1 The Classical approach was originated by Smith (1776) and was further interpreted and developed by Keynes (1920), Lewis (1954), Kaldor (1957), and Bourguignon (1981). According to this approach, saving rates are an increasing function of wealth and inequality therefore channels resources towards individuals whose marginal propensity to save 1. The socio-political economy approach provides an alternative mechanism: equality diminishes the tendency for socio-political instability, or distortionary redistribution, and hence it stimulates investment and economic growth. See the comprehensive survey of Benabou (1996b).