I kind of believe the title. If you're not religious, I think, your mind is more open, therefore more intelligent. Because, I think, religion clouds our minds. We only believe certain things because our religion says so. And we don't believe certain things because our religion says so. But not everyone's like this, of course. But this is how I see it. I think if no one was religious then, MAYBE, everyone in the world can get along a LITTLE better. We won't have the clouds blocking our judgment so much.
Thats all very superficial though. None of that deals with intelligence. Intelligence can be defined in many ways, but i have never come across a study that defines it as "open mindedness" . Now that does correalate with ignorance, but that is serperate from intelligence. Close and open mindedness have nothing to do with whether or not you do or dont believe in a god. Everybody is ignorant of something and usually is no more willing to believe in one side of a debate than the other if it contradics your own beliefs, reguardless of what you believe.
And everybody believes in a lot of things because some athority figure (parents, teachers, culture, ect.) says so. Thats something everybody has in common.
As for "clouding judgement". Well drugs and acohol seem to do that. Emotion and stress can to. That really has nothing to do with a belief god either, at least not in a contempory sense.
and history shows that just because people look, think, and act alike doesn't mean they will get along. Religions, countries,music, and politcial beliefs have been broken apart simply because one guy decides he knows the "truth" and everyone else is stupid.
As for what intelligence is, i dont know. But i believe it is how one interprets and categarizes information, and not simply the accumalation of information. What that has to do with religion? I have no idea. peace over war