How to tell if you're listening to a smart person

I had never thought of this ad hoc intelligence test -- Stephen Dubner on the Freakonomics blog says:

As a writer, I enjoy listening to people speak and, when they’re in the middle of a particularly interesting sentence, I try to imagine how I’d like to see it finished.

Usually I am disappointed. But with some select people, the payoff is far greater than I could have imagined. They have something to say that’s remarkably insightful or unexpected or even just articulate in a way that takes your breath away.

I could do without the overstated "takes your breath away" rhetoric, but aside from that, it seems like a useful test, though there's an obvious risk of becoming overly judgmental.

Dubner gives 3 examples: President Obama, classical pianist Glenn Gould, and some sports guy who wrote a book about some other sports guy. Click the above link if you're interested in the specific explanations.

Dubner adds:

In each case, the subject spoke with what I can only characterize as total intelligence — a lot of mental horsepower, to be sure, but also nuance, precision, conceptual and practical elements combined in the same sentence, and psychological astuteness.

I guess, therefore, that if I were asked to define what it means to be “smart” in this day and age, those are the characteristics I’d list. I know a lot of super-brainy people who don’t express themselves well; I know a lot of psychologically astute people who haven’t a whiff of organization or precision about them; I know a lot of articulate people who can’t see the big picture. But if I were friends with either Obama, [that sports guy], or Gould, I’d have to say that they were the smartest people I know. (Sadly, I’m not.)

I don't understand why he focuses on "President Obama's first press conference" (the prime-time address in early February where he pitched the economic stimulus plan). I'm fine with Dubner using Obama as an example of a smart person. But as for that specific press conference, I agree with this review — it was unusually long-winded and meandering. ("Obama seemed like he was channeling a particularly loquacious combination of Joe Biden, Bill Clinton, and the ghost of Hubert Humphrey. . . . Obama radiated the sense of a leader who has digested too many economic briefings and memorized too many talking points in preparation for his primetime rendezvous with the public.")

It's also weird that he starts out equating intelligence with finishing your sentence with unexpected insight, but he never gives any example of a sentence by any of those 3 people (or anyone else) that ended unexpectedly. So I was disappointed with how he finished his blog post.

As for Dubner's analysis of what makes someone intelligent — "nuance," "precision," "conceptual"/"practical," and "psychologically astute" — I'm not sure. Someone who had all those qualities in their conversation would probably be interesting to listen to. But do they add up to "intelligence"? Maybe they add up to "how to sound intelligent."

UPDATE: My dad has a good intelligence test:

whether a person, if asked to explain himself, is capable of doing so in different, clearer terms than he used the first time.

Unfortunately, it's all too common to see people trying to project intelligence through precisely the opposite approach: persistently explaining things in obfuscatory terms. I keep coming back to this passage from an essay by John Kenneth Galbraith (previously blogged):

Complexity and obscurity have professional value—they are the academic equivalents of apprenticeship rules in the building trades. They exclude the outsiders, keep down the competition, preserve the image of a privileged or priestly class. The man who makes things clear is a scab. He is criticized less for his clarity than for his treachery.