I read the article and the abstract, unfortunately have not located the full study, but it seems rather low quality evidence to be making such correlative statements. The biggest question I have about how they came to their conclusions is: Was there any assessment of their religious fundamentalism prior to their TBI? It sure would be nice to have that assessed in order to determine stronger correlation to the TBI impacting their level of fundamentalism. If they were fundamentalists before TBI, I could easily see the experience of TBI (and their survival of such) as only further encouraging such fundamentalist belief (most fundamentalists would easily credit God's intervention in their survival and recovery, thus providing a positive feedback loop to their already clung to beliefs). If the converse were true and they were less or not at all fundamentalist prior to TBI, that would certainly impact their findings as well. Certainly a fascinating area of study, but far more research is needed to make any relevant statements.

And here I thought it was because their medulla oblongata was enlarged

I am led to wonder if the author of the article has lesions on his prefrontal cortex. Every paragraph says essentially the same thing over and over, and there are at least ten paragraphs. The essence is that there is a correlation between damage to the front part of the brain and fundamentalist religious belief. A confused and bungled statement near the end indicates (I think) that brain inflexibility is a cause for a fifth of fundamentalist views as determined by the study.

I am extremely skeptical of the study. If the scientists are truly interested in rigid thinking patterns they should look, not only at religion but at all areas of human thinking. For many students for example, their textbooks are gospel, not to be questioned. And many cling desperately to a materialist interpretation of reality even when science has moved on.

It’s a pretty ridiculous study from the get-go, based on the religious beliefs of infantry soldiers with brain damage. That is a very small group. Measure the religious beliefs of PHDs with brain damage and you’d get a different result I’ll bet. A high percentage of them are probably atheists. You could then yell that brain damage causes atheism.

How does all this relate to the so-called, and mislabeled “Bible Belt”? Contrary to what is often thought, religious fundamentalism is not an old southern tradition. Christian fundamentalism arose in the twentieth century and was created by churches in the Northeast, specifically New England. Fundamentalism as a doctrine only gained a significant foothold in the Southern Baptist Association in the 1940’s.

Anyone who doggedly opposes my opinion has brain damage.

It is not clear to me from the article what caused the alleged damage. What appears to actually be the case is that certain kinds of damage are consistent with promoting fundamentalism but even they admit that it's 80% other effects that influence fundamentalism. So unless I'm completely misunderstanding something, this article doesn't say all fundamentalists are brain damaged or that all fundamentalism reflects brain damage. I think the headline is designed to attract eyeballs but the article itself simply establishes a potential association (among many), not a cause.

Or to take advantage of an already-overused phrase, "it's a nothing-burger".