Here's a fairly short article trying to explain who votes Republican and who votes Democratic. It's interesting but not definitive. We, for instance, don't fit in it -- we both have Maters of Science degrees and go to church weekly and live in a rural area -- depending on your definition of rural. (we have 5 acres, the smallest lot allowed in the area. Across the street our neighbor has 35 acres, and down the street there's a 500 acre dairy farm and creamery. but we are 10 miles from a small city.)
Anyway, this article is just for fun. But it's from Five Thirty Eight so it should be reliable.