Dr. Jerry Coyne, biologist and author of Why Evolution Is True, wrote a fantastic blog post that shows the correlation between income inequality and religiosity in countries around the world. Coyne gave a talk about evolution, religion, and science, and societal dysfunction where he argues that lack of acceptance of evolution is linked to high religiosity, which itself is linked to poor societal health. A commenter crunched some numbers for specifically the United States:
[Dr.] Harry [Roy, professor of biology at Rensselaer Polytechnic Institute in New York] found some relevant data in the United States, crunched the numbers, and did a statistical analysis. He left comments and a link to the analysis, after my post. And he’s kindly done a bit more analysis and allowed me to reproduce it here. What he found is precisely the same relationship among states (using the HDI) as I found among countries: American states with lower HDIs are more religious.
First, a portrait of American religiosity taken from a 2009 Gallup poll:
As we know, the south is really religious (just go there if you doubt that!), and the northeast and west coast states much less so.
And below is a national map of the Human Development Index (HDI) from Wikipedia. This index is a measure of societal well being that differs from the “Successful Societies Scale” (SSS) that I used in my talk at Harvard. The HDI uses a set of traits that differ from those used in the SSS: the former amalgamates three traits (life expectancy, education, and income), while the latter combines 25 traits, including corruption, income disparity, child mortality, access to medical care, suicide rates, and so on. Unlike the SSS, under which the U.S. ranks very low among first-world nations, the HDI places the U.S. at the top when the index is not adjusted for inequality among residents, but falls much lower when adjusted for inequality (see the Wikipedia article on the HDI at link above). The disparity may be due to the inclusion of income inequality in the adjusted HDI; income inequality is highly positively correlated with religiosity across 71 nations.
The south is not so great here, the northeast (and two states on the west coast) are better. That suggests a relationship between religiosity and well being as measured by the HDI.
After crunching the data, Dr. Roy produced this correlation between the religiosity of the 50 states and their ranking on the HDI:
As you see, we have the same negative relationship between well-being and religiosity that we saw for different countries of the West. The correlation here is r= – 0.66897, and the probability (“p”) that this correlation would arise by chance is p = 0.00000012. (A value of p less than 0.05 is conventionally used to show a significant relationship.) This relationship, then, is not only striking but very highly significant in a statistical sense. Harry put a least-squares regression line through the data; its slope is also highly significant.
The only thing to determine is if religion is the cause or the effect of income inequality. There could also be some other variable(s) that is/are driving both indicators. But whatever the cause, it stands to reason that your best bet for a good, healthy society to live in is one that accepts evolution! Now why would god do that?