As I’ve said a hundred times before and will say a hundred times again, perhaps the single umbrella that covers all of intelligence is the ability to adapt: to take whatever situation you’re in and turn it around to your advantage.

But what does that really mean?

More precisely, I define intelligence as the brain’s capacity for behavioral adaptability, which I define as:

Behavioral adaptability is the brain’s ability to use whatever body it’s in as a tool to use whatever environment it’s in as a tool to minimize the cost-benefit ratio of whatever incentive structure it has.

So there are many reasons why the correlation between intelligence and success would be far from perfect.

Different people have different bodies.  Two people with equal intelligence could differ enormously in physical attractiveness or athletic talent, and that could mean the difference between extreme wealth and poverty.

Different people could have different environments.  One man is born to a family of investment bankers while another man is born in rural poverty.  The former will likely be much more successful even if the latter is much more intelligent.

Different people have different incentive structures.  One man’s idea of success could be raking in millions as a CEO, while another man’s idea of success could be sleeping in everyday until noon and then watching TV the rest of the day.

Given that life is such an unlevel playing field, and then on top of that, success can be defined in so many ways, it is truly remarkable that the correlation between IQ and money is as high as it is.  This strongly suggests IQ really is measuring behavioral adaptability.

But the clearest measure of intelligence is not how successful you are, because that’s just a test of your ability to adapt to your body, your environment and your incentive structure, which might not be that difficult…the clearest test is how well your intelligence could tell others how to use their bodies and environments as a tool to their advantage.

A great example of this is the character Master Blaster from the Mad Max movies.  Blaster is a muscular mentally retarded giant, but despite his incredible physical advantages, he lacks the basic intelligence needed to turn them around to his advantage.  Luckily, he has a high IQ dwarf named Master who sits on his shoulder to tell him how to exploit his physical strengths in fights and other situations, essentially serving as Blaster’s brain every waking hour of the day.

So this is the ultimate test of intelligence.  Instead of being given math problems and vocabulary questions, we should be given someone else to control every minute of the day, perhaps though virtual reality, and the better job we do in telling that person or animal how to reach his specific goals, the higher our score.  In a way political consultants and Hollywood agents take this test for a living.  Lacking the good looks to run for office or star in movies themselves, they manage the careers of politicians and actors. Indeed Karl Rove was known as Bush’s brain:

We could start the test off controlling a really advantaged person; someone blessed with a strong body, rich environment, and simple goals, thus turning the situation to his advantage would require very little turning.

We would then be given gradually harder problems: tell this wheel chair bound overweight lazy person living in poverty what do every minute of the day so they become rich and powerful, yet still get to sleep in until noon.

I think one’s score on such a test would correlate as well with conventional IQ tests as conventional IQ tests correlate with one another, but it would capture the evolutionary basis of intelligence:  Humans lacked physical advantages so we had to use our behavior to our advantage.  That’s why intelligence evolved.