From Psychology Today:
New Hampshire is the least religious state in the union and Mississippi is the most religious according to Gallup data. A minority of New Hampshire residents see religion as being important in their daily lives (46 percent) in contrast to a large majority of Mississippians (85 percent). How can such huge differences be explained?
The Gallup organization (who collect the data in phone surveys) notes on their website that state differences in religiosity are poorly understood, and they are correct. Astonishingly, researchers have never crunched the numbers in an effort to understand religious differences within the country. So I decided to be the first to do so.
Quality of life
I wondered whether state differences might follow a similar pattern as that already established for different countries. Various researchers report that religion declines as the quality of life improves. Evidently, religion acts as a form of emotion-focused coping in the jargon of clinical psychology. This means that miserable living conditions drive people into churches.
This raises the question of whether New Hampshire resembles Europe in having a good quality of life and weak religion. Is Mississippi more like sub-Saharan Africa in having a lower quality of life and stronger religion?
I measured quality of life in terms of the state human development index. This taps good health, and educational attainment, in addition to the size of the state economy per resident. A poor quality of life was a moderately strong predictor of religiosity accounting for just over a third of state differences.
The quality of life in Mississippi was close to the bottom on the human development index and that in New Hampshire was close to the top. So the pattern for U.S. states confirms that found by comparing different countries. Religion thrives on misery and chokes on prosperity.
Yet, there is more to the story than this. Another obvious difference between New Hampshire and Mississippi is that Mississippi has the most African American residents and New Hampshire has close to the fewest.
Ethnic group differences
African Americans are more religious than the rest of the population. So it is hardly surprising that states having a greater proportion of African Americans are significantly more religious, although the strength of the effect was surprising given that this group is a small minority of the U.S. population.
It turned out that African American population was as strong a predictor of state religiosity as the quality of life (human development index) according to regression analysis.
This raised the further question of why African Americans are so much more religious than the rest of the population. Sociologists would argue that the African American church served as a bastion against racism and the stress of living in a society where African Americans still have fewer opportunities despite representation in the highest political office of the presidency.
I used location in the South as a measure of racism because these states practiced segregation within living memory. Stress was measured in terms of the proportion of the population suffering from high blood pressure. This happens to be a fairly sensitive measure of social stress that responds to out-group status, the social stigma of being physically unattractive for young women, and so forth.
In a further analysis, I found that the impact of ethnic group on religiosity was entirely mediated by stress (high blood pressure) and racism (residence in a Southern state).
State differences in religiosity were neglected by researchers. Yet, they conform to a more general pattern across countries. Wherever living conditions are more difficult, people are more religious whether the difficulty is due to economic under development, or to a legacy of racism.