That's very interesting. ''Instinct'' is something typically used by people who frequently are emotional decision makers. So it does make sense that they would be more religious. Intelligence is something very difficult to define. I don't know how the researches defined it, but usually the mainstream methods to measure it have many flaws. Intelligence has so many multiple components that it is impossible to measure just by the ability of someone to solve number sequences and put shapes in the correct order. People who learn to practice their critical thinking, no matter what educational background they have, are the ones that as you said, overcome instinct to reason. The association with ''depression'' is truly interesting and I would love to read more about that!