I can of course make no authoritative claims here, but I have noticed one overarching theme among smart people: they ask questions. When someone explains something new to me, I’ll usually just nod my head like I know what they’re talking about. If I don’t understand something, I’ll just Google it later. After all, I don’t want this person to think I’m a moron. Smart people are different. If they don’t understand something, or even if they think they understand something, they’ll ask questions.