Humans have two facets, biological and social. Whereas it is a common idea that poor social conditions affect the biological facet for instance by reducing life expectancy, there are few known cases where an economic effect is affected by the biological facet in a way which can be predicted. The purpose of the paper is to present such a case. In other words, we are going to decompose an economic phenomenon into its biological and social components, a step which provides a marked conceptual simplification. The economic phenomenon that we consider here is one of the most basic that one can think of, namely the relationship between personal income and life expectancy. Intuitively, one is not really surprised that wealthy people live longer than poor people. Here, however, we show an effect which is far less obvious, namely the fact that this relationship does not hold at both extremities of the lifespan interval. The disconnection between income and neonatal (i.e., in the first 28 days after birth) mortality is quite impressive. This observation is particularly significant on account of the fact that the infant mortality (i.e., in the first 365 days after birth) is often taken by economists as a proxy of development when no reliable income data are available. This indicator may be valid for very poor countries where the burden of death due to infectious diseases remains very high, but it is not valid in developed countries such as those considered in this paper. More specifically, we explore the influence of income on mortality by age, separately in France, the United States and South Korea. The same pattern appears for the curves of the (income-mortality) correlation as a function of age. We conjecture that this pattern will be observed in any developed country where the test can be performed. For the test to be possible the main requirement is the availability of income and age-specific mortality data at regional level.

人有两个方面，生物学的和社会的。虽然普遍认为恶劣的社会条件会影响生物学方面，例如通过降低预期寿命，但很少有已知的案例表明经济影响以可以预测的方式受到生物学方面的影响。本文的目的就是展示这样一个案例。换句话说，我们将把一种经济现象分解为其生物和社会成分，这一步骤提供了显着的概念简化。我们这里考虑的经济现象是人们所能想到的最基本的一种，即个人收入与预期寿命的关系。直觉上，富人比穷人活得更久并不让人感到惊讶。然而，在这里，我们展示了一个远不那么明显的效果，即这种关系在寿命间隔的两端都不成立。收入与新生儿之间的脱节（即，在出生后的前 28 天）死亡率是相当可观的。由于婴儿死亡率（即，在出生后的前 365 天）通常被经济学家用作在没有可靠收入数据可用的情况下的发展指标。该指标可能适用于传染病死亡负担仍然很高的非常贫穷的国家，但不适用于本文所考虑的发达国家。更具体地说，我们分别在法国、美国和韩国探讨了收入对年龄死亡率的影响。作为年龄函数的（收入-死亡率）相关曲线出现相同的模式。我们推测这种模式将在任何可以进行测试的发达国家中观察到。为使测试成为可能，主要要求是提供地区层面的收入和特定年龄死亡率数据。