A pair of Harvard researchers recently examined 40 years of data from dozens of countries, trying to sort out the economic impact of religious beliefs or practices. They found that religion has a measurable effect on developing economies – and the most powerful influence relates to how strongly people believe in hell.

That hell could matter to economic growth might seem surprising, since you can’t prove it exists, let alone quantify it. It stands as one of the more intriguing findings in a growing body of recent research exploring how religion might influence the wealth and prosperity of societies. In recent years, Italian economists have presented findings that religion can boost GDP by increasing trust within a society; researchers in the United States showed that religion reduces corruption and increases respect for law in ways that boost overall economic growth. A number of researchers have documented how merchants used religious backgrounds to establish one another’s reliability.

The researchers, Robert Barro and Rachel McCleary, find intriguing relationships:

Their results show a strong correlation between economic growth and certain shifts in beliefs, though only in developing countries. Most strikingly, if belief in hell jumps up sharply while actual church attendance stays flat, it correlates with economic growth. Belief in heaven also has a similar effect, though less pronounced. Mere belief in God has no effect one way or the other. Meanwhile, if church attendance actually rises, it slows growth in developing economies.

Other social scientists’ findings have been consistent with Barro and McCleary’s results, reviving classic Weber-esque questions about how religion affects economies:

On one level, the connection seems intuitive: All the major religions extol virtues like self-discipline, sacrifice, and thrift. Some even preach that earthly success translates to good things in the afterlife, a kind of gold-plated stairway to heaven. Religion can, quite directly, affect what you earn – fundamentalists and evangelicals in the United States tend to have lower savings rates and incomes than members of other religions, in part because they have larger families and give away more of their money.

Some find religion prompts specific behaviors that spark economic growth:

Charles M. North, an economist at Baylor University, argues that private property protections developed by the Church to guard against grasping secular rulers gave Catholic – and eventually Protestant – nations stronger protections for individual rights than other nations, creating incentive for individual success. Similarly, literacy seems clearly connected with economic development, and mass literacy is a Protestant invention, says Robert D. Woodberry, a sociologist at University of Texas at Austin. He has mapped how missionaries spread literacy, technology, and civic institutions, and finds that those correlate strongly with economic growth. He argues in part that this helps explain why the once-poor but largely Protestant United States surpassed rich, Catholic Mexico after 1800.

The bottom line:

The work is preliminary, but offers the hope of useful findings. Knowing exactly how and when God influences mammon could lead to smarter forms of economic development in emerging nations, and could add to our understanding of how culture shapes wealth and poverty. And it stands as part of a larger movement in economics, in which the field is looking beyond purely material explanations to a broader engagement with human culture, psychology, and even our angels and demons.