color are the poorest in the world, those where average per-capita incomes (called by economists GDP, gross domestic product) are less than $2,000 annually. Most of Africa is in this color, as are Afghanistan, Haiti, and parts of Southeast Asia (for example, Cambodia and Laos). North Korea is also among this group of countries. The countries in white are the richest, those with annual income per-capita of $20,000 or more. Here we find the usual suspects: North America, western Europe, Australasia, and Japan.
Another interesting pattern can be discerned in the Americas. Make a list of the nations in the Americas from richest to poorest. You will find that at the top are the United States and Canada, followed by Chile, Argentina, Brazil, Mexico, and Uruguay, and maybe also Venezuela, depending on the price of oil. After that you have Colombia, the Dominican Republic, Ecuador, and Peru. At the bottom there is another distinct, much poorer group, comprising Bolivia, Guatemala, and Paraguay. Go back fifty years, and you’ll find an identical ranking. One hundred years: same thing. One hundred and fifty years: again the same. So it is not just that the United States and Canada are richer than Latin America; there is also a definite and persistent divide between the rich and poor nations within Latin America.
A final interesting pattern is in the Middle East. There we find oil-rich nations such as Saudi Arabia and Kuwait, which have income levels close to those of our top thirty. Yet if the oil price fell, they would quickly fall back down the table. Middle Eastern countries with little or no oil, such as Egypt, Jordan, and Syria, all cluster around a level of income similar to that of Guatemala or Peru. Without oil, Middle Eastern countries are also all poor, though, like those in Central America and the Andes, not so poor as those in sub-Saharan Africa.
While there is a lot of persistence in the patterns of prosperity we see around us today, these patterns are not unchanging or immutable. First, as we have already emphasized, most of current world inequality emerged since the late eighteenth century, following on the tails of the Industrial Revolution. Not only were gaps in prosperity much smaller as late as the middle of the eighteenth century, but the rankings which have been so stable since then are not the same when we go further back in history. In the Americas, for example, the ranking we see for the last hundred and fifty years was completely different five hundred years ago. Second, many nations have experienced several decades of rapid growth, such as much of East Asia since the Second World War and, more recently, China. Many of these subsequently saw that growth go into reverse. Argentina, for example, grew rapidly for five decades up until 1920, becoming one of the richest countries in the world, but then started a long slide. The Soviet Union is an even more noteworthy example, growing rapidly between 1930 and 1970, but subsequently experiencing a rapid collapse.
What explains these major differences in poverty and prosperity and the patterns of growth? Why did Western European nations and their colonial offshoots filled with European settlers start growing in the nineteenth century, scarcely looking back? What explains the persistent ranking of inequality within the Americas? Why have sub-Saharan African and Middle Eastern nations failed to achieve the type of economic growth seen in Western Europe, while much of East Asia has experienced breakneck rates of economic growth?
One might think that the fact that world inequality is so huge and consequential and has such sharply drawn patterns would mean that it would have a well-accepted explanation. Not so. Most hypotheses that social scientists have proposed for the origins of poverty and prosperity just don’t work and fail to convincingly explain the lay of the land.
THE GEOGRAPHY HYPOTHESIS
One widely accepted theory of the causes of world inequality is the geography hypothesis, which claims that the great divide between rich and poor countries is created by geographical differences. Many poor countries, such as those of Africa, Central America, and South Asia, are between the tropics of Cancer and Capricorn. Rich nations, in contrast, tend to be in temperate latitudes. This geographic concentration of poverty and prosperity gives a superficial appeal to the geography hypothesis, which is the starting point of the theories and views of many social scientists and pundits alike. But this doesn’t make it any less wrong.
As early as the late eighteenth century, the great