Economist Luis Angeles suggests (in his paper Income inequality and Colonialism) that we can lay part of the blame for income inequality in the new world on colonialism:
Our paper’s main point is that colonial history is a major explanatory factor behind today’s large differences in inequality among the world’s countries. We have reviewed the different colonial experiences of the last five centuries and have classified them in 3 broad categories. Of these three, we argued that one clearly produced and sustained highly unequal societies. This high inequality group is the one where colonialism brought into the country an amount of European settlers whose number was considerable but still inferior to that of the local population. This minority was able to concentrate most of the countries’ income in their hands, mainly by excluding the rest of the population from owning land or mining resources. Moreover, and with the exception of Algeria, it was this minority who took all political power once these countries became independent. This allowed high inequality to remain a characteristic of these countries up to our times.
It is important to make a distinction here between inequality – the subject of this paper – and general lack of growth and poverty. In this paper, the countries that are more unequal (in Latin America, Carribean, and Southern Africa) also generally have higher GDP than countries that are less unequal (e.g. India).
There is no contradiction whatsoever between the fact that Settler colonies became highly unequal and that these same colonies achieved a higher level of production per capita than Peasant ones. This relative economic success was precisely the result of the European settlers’ growth record. By their cultural background they were able to put at least partially in place the technology and institutions that made the economic superiority of Europe and the New Europes.
The paper is also useful for its brief survey of literature on colonialism and economic evolution, and if the subject interests you see also Guns, Germs, and Steel: The Fates of Human Societies:
Acemoglu et al. (2001) argue that the pattern of European settlement in the colonies determined the type of institutions that these countries developed and that these institutions are a major factor behind their economic backwardness. In those regions where few Europeans settled, Europeans created “extractive states” and the resulting institutions “…did not introduce much protection for private property, nor did they provide checks and balances against government expropriation.” On the other hand, the authors also propose that the countries that received a large number of settlers “tried to replicate European institutions” and therefore created the right set of rules encouraging future economic growth.
By way of New Economist, the paper is available on SSRN and also from the University of Manchester (PDF). If you’d like to check the correlation, the World Income Inequality Database (WIID) may be useful, as also the UN Human Development Report (PDF).