It is a well known fact that economic development and distance to the equator are positively correlated variables in the world today. It is perhaps less well known that as recently as 1500 C.E. it was the other way around. The present paper provides a theory of why the ‘latitude gradient’ changed sign in the course of the last half millennium. In particular, we develop a dynamic model of economic and physiological development in which households decide upon the number and nutrition of their offspring. In this setting we demonstrate that relatively high metabolic costs of fertility, which may have emerged due to positive selection towards greater cold tolerance in locations away from the equator, would work to stifle economic development during pre-industrial times, yet allow for an early onset of sustained growth. As a result, the theory suggests a reversal of fortune whereby economic activity gradually shifts away from the equator in the process of long-term economic development. Our empirical results give supporting evidence for our hypothesis.

众所周知，当今世界经济发展与距赤道的距离是正相关的变量。也许不太为人所知的是，就在公元 1500 年，情况恰恰相反。本文提供了一种理论，解释为什么“纬度梯度”在过去五年中改变了符号。特别是，我们开发了一个经济和生理发展的动态模型，其中家庭决定其后代的数量和营养。在这种情况下，我们证明，相对较高的生育代谢成本可能是由于远离赤道的地区对更高耐寒性的积极选择而出现的，这将在工业化前时期抑制经济发展，但会导致早期爆发的持续增长。因此，该理论提出了一种命运逆转的现象，即经济活动在长期经济发展过程中逐渐远离赤道。我们的实证结果为我们的假设提供了支持证据。