I get what you're saying but I think you have it backward. From my one and only experience of serving on a jury in a murder case, smart people are the only ones who will weigh the evidence. Dumb people figure that the cops wouldn't have arrested you if you weren't guilty, so why are we even wasting our time? On my jury there were about 3/14 smart people, but one of them was obviously racist, so it was up to two of us to try to debate the evidence as presented. In the end the guy was obviously guilty, but I got the sense that the rest of the people in the jury were just kinda pissed off at me that I wanted to talk about possible scenarios in which the defendant may not have done it (that whole reasonable doubt thing). You need to be smart and imaginative to come up with alternate narratives to the prosecutions. Working this all out, I'm wrong too. You actually never want dumb jurors, guilty or innocent.