SPAIN’S CONQUEST of the Inca empire in the 16th century was catastrophic for the Incas. Within four decades the native population fell by 75-90%. Old-world diseases were mostly to blame, but forced labour played a part. Missionaries coerced Spain’s new subjects to convert to Catholicism, while viceroys razed Inca buildings.
Yet Inca culture proved persistent. Some 10m people in Peru and nearby countries speak Quechua, the Incas’ language of empire, whose use the Spaniards discouraged. Peruvians still hand-weave textiles with bright patterns. A new paper, by Ana Paula Franco of Harvard, Sebastian Galiani of the University of Maryland and Pablo Lavado of the University of the Pacific in Lima, unearths another example of the Incas’ durable achievements: Peruvians still benefit from 15th-century infrastructure.
The Incas ruled over 10m square km (3.8m square miles). To collect taxes, deploy troops and exchange messages with remote lands, they built 30,000km of stone roads, dotted with warehouses to store food and water. The biggest cities in modern Peru are on or near the coast, far from the Incas’ most important routes. This makes it possible to study the effects of pre-Columbian infrastructure with little distortion from later urbanisation.
To test if the Inca road, the Incas’ main thoroughfare, has boosted modern living standards, the authors split the map into small squares. For four indicators of welfare—wages, nutrition, maths-test scores and years of schooling—they compared levels from 2007-17 in squares crossed by the road with those in neighbouring squares not on its route. On every measure, residents of roadside squares fared better than those in adjacent ones, even after controlling for differences in such factors as the slope of terrain and the presence of rivers. Women gained more than men.
How did the road grant such long-lived blessings? The Spaniards used it to ship silver and turned the warehouses into profitmaking shops, often staffed by women (possibly inculcating more equal gender roles). This made land near the road unusually valuable, encouraging colonisers to settle there. The authors argue that Spaniards who moved in claimed legal title to their landholdings and built schools and new roads in the vicinity, creating enduring property rights and public goods. Today, the presence of the Inca road alone accounts for a third of the observed difference in levels of formal land ownership between dwellers on the road and those in nearby areas. It explains half the difference in the number of schools.
Might modern roads along the corridor explain more of that uplift in welfare than the ancient one? The scholars investigated that, too. The Inca-road squares do have twice as many kilometres of road as adjacent ones do. However, on average, even when comparing squares with similar densities of road, people living in those along the old route earned more money and had more years of schooling.
The builders of the Inca road might be pleased that the areas they improved remain relatively prosperous (though they are poorer than the coast). They would be less happy that one reason is the usefulness of their handiwork to colonisers. But today, the Incas’ descendants are also among the beneficiaries of their labour. ■
Source: “Long-term effects of the Inca road” by A. P. Franco, S. Galiani and P. Lavado, National Bureau of Economic Research, 2021