This Harvard graduate makes a few conclusions about smart people:

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. I distinctly remember, as an immature and perhaps arrogant freshman, a guest lecture in one of my classes. After explaining what I thought was a straightforward concept, the guest lecturer asked if anyone had any questions. Looking around the room, every student simply nodded, indicating everything was clear. A question, however, came from a tenured professor who had undoubtedly been exposed to the material before. At the time, I thought nothing of it, and perhaps even thought that I was smarter than the professor because I understood a concept he/she didn’t. Now, I am confident that this professor did not ask the question just to make the guest lecturer feel better, to start a discussion, or anything else. The intonation of the question and the intensity with which the professor listened to the response definitively suggested that the professor’s question was genuine, and that the answer was of great importance.

Based on the research and findings of so many of the students and professors here, it’s clear that this trend is no accident. Not only do smart people ask questions when they don’t understand something, but they also ask questions when the world thinks it understands something. Smart people challenge the very limit of human understanding, and push the envelope of what’s possible farther than many people would argue it’s meant to be pushed. Smart people don’t take claims at face value, and smart people don’t rest until they find an explanation they’re comfortable accepting and understanding.

There’s a lot to add here, especially in terms of introversion and extroversion of individuals and their ability/desire to ask questions. But the author’s point is a good one.