Religious fanaticism. Ultra-religious people are insane.

Religious fanaticism seems to be related to the hippocampus. That is a lot of what I have seen is the idea of rituals as cause and effect things. That is people tend to think "I did this ritual and thus and thus happened afterwards." So they are connected.

Pigeons have the same thing. If you randomly reward pigeons they will on their own come up with a superstitious belief  system.  They think, "Since I did thus and thus before the food appeared therefore that must have been the cause of the food appearing." You thus can get a whole room full of superstitious pigeons doing all kinds of nonsense because they think that that is the thing that caused the food to appear because it was the thing that they did one time before it appeared.

But if the hippocampus is damaged the effect is much stronger. There is much less of an ability to tell the difference between cause and effect random correlation.

That is religious fanaticism is biological.

Lithuanian yeshivas are obviously aware of this and therefore discourage religious fanaticism. Learning Torah and keeping Torah are one thing. Religious fanaticism is something entirely different.

Thus you get a situation where most Ultra-religious people are insane as we see in reality and in biology..
So while there are some drawbacks to the average Litvak yeshiva, (because it is an human institution like all others  that has failings.) still it is a huge advantage to the other kinds of insanity out there in the ultra religious world.