Years ago when I was frequenting a couple of local bars, I decided to try an experiment: I purposefully dumbed down my personality to see what those around me would do. I made a LOT of friends - far more than I would 'normally'. Seemed like everyone liked me. And this was after several months of frequenting the bars without changing my personality. I talked the sportsball, and the beer, and made ridiculous comments about the females. And whatever one of the bar denizens was up to talk about, I was right there with them. And I found out a couple of things. First, when I decided to end the experiment, things more or less went back to how they were before. These 'friends' I had made didn't stick. And second, doing this was EXHAUSTING. It was literally serious effort to make myself dumb. So the conclusion? Yes, some (maybe most) people are capable of really communicating only with people within a certain range of their own IQs. But it's not really worth dumbing yourself down for people. Maybe, if you're on the lower IQ end of the room, working on raising yourself up to another level would be beneficial - but not the other way around.