Cross-National Determinants of Income Inequality: A Replication and Extension Using Ecological-Evolutionary Theory

Abstract

Simpson (1990) suggests that curvilinear specifications for educational enrollments and political democracy are appropriate in modeling the cross-national determinants of income inequality, whereas the well-known curvilinear effect of national wealth, or the logic of industrialism hypothesis, is mediated by education and democracy. This analysis uses the same data on income inequality to replicate Simpson's research. Findings include the following: (1) most of Simpson's central findings can be replicated; (2) using a different measure of development, national wealth does exhibit a direct, curvilinear relationship with income inequality; (3) world-systems/dependency theory finds less support; and (4) agricultural density, used as a proxy for the social and physical carrying capacities of rural areas, has a robust, negative influence on income inequality, in accord with ecological-evolutionary theory. While attempts at synthesis have been made (Milner 1987), no comprehensive theory has emerged to explain income distributions within nations, although many theories have informed these investigations in the past. Specifically, modernization theory, dependency/world-systems theory, a variety of political theories, and ecological-evolutionary theory all suggest variables that may find purchase on this topic. The purpose of this research is to re-examine existing models of income inequality that attempt to test multiple theories simultaneously. In addition, this analysis introduces another hypothesis suggested by ecological-evolutionary theory and investigates its independent contribution to explanations of income distribution. * An earlier version of this article was presented at the American Sociological Association meetings, August 1992. I would like to thank Ansari Ameen and Wen Lang Li for their assistance in the preparation of this manuscript. Also, thanks go to Kenneth Bollen, Glenn Firebaugh, William Form, Craig Jenkins, Gerhard Lenski, Miles Simpson, Kazimierz Slomczyn'ski, and three anonymous reviewers for their helpful comments and suggestions. Address all comments to the author, Department of Sociology, 190 North Oval Mall, 300 Bricker Hall, The Ohio State University, Columbus, OH 43210-1353. ? The University of North Carolina Press Social Forces, December 1992, 71(2):339-363 This content downloaded from 207.46.13.115 on Sat, 08 Oct 2016 05:24:12 UTC All use subject to http://about.jstor.org/terms 340 / Social Forces 71:2, December 1992