Like many people, I consider myself a life long learner. When I am learning something new the world seems a better place. I think there are three parts of smarts: what you get, what you develop, and what you do with it.
What You Get
Every brain comes pre loaded with natures gift of intelligence. There are more variables in the brain creating process than anyone can imagine and differences both subtle and dramatic are evident even in the brains expected to be the same -- like those of identical twins. Derived from a mixture of its ancestors gene pool and the supply of oxygen and nutrients during what must be a highly precarious time of early brain development, a baby is born with the raw materials of intelligence presented as if a gift. We don't really know how this all works. We have learned that tragedies like exposure to dangerous chemicals or oxygen starvation can subtract from the intelligence nature gave us. But we have not discovered any way to build a bigger better brain than nature would give us on that zero birthday.
What You Develop
On that day the gun goes off and everyone starts to build on top of the foundation nature gave them. The early years are dominated by the way the brain operates the mechanical controls of the body then rapidly moves to the mental gymnastics required to throw a ball, turn a phrase, or manipulate an algorithm. This nurture part of brain development is both constant and perpetual. Learning is a lifelong pursuit driven by personal choices from a very early age. Some brains are exposed to bats, balls, and scoreboards, some get music, and others get languages making the path of brain development as unique as the face in front of it. Some brains are just naturally good at chess. Some brain owners are just very interested in learning about chess. The grand master has both the natural gift and the nurtured development combined into a powerful ability.
What You Do
Somewhere along the way nature's gift of mental foundation combines with a person's interests, brain development and experiences and a person gets a personality. This personality likes certain things and whenever possible chooses to do more of the things it likes. The dictionary definition of aptitude is "a natural ability to do something" but in the context of the framework here, the "natural" also includes a great deal of nurtured development. People feel good and are rewarded when they do something well, and then do more of it and with a dash of competitive spirit some even work hard to be the best or smartest in their field.
There is a rarified group of lifelong learners with truly Olympic caliber brains. They were lucky enough to win nature's brain lottery, and were blessed with ideal learning conditions early in life, and then spent little time distracted by activities that did anything other than exercise their thinking muscles. It is not terribly likely that these people are to be found alone on a mountain top somewhere. Like other competitors, they want to be around people that push them to develop their brains even further.
If I were going to go looking for them, I would start at universities -- where the stated mission is to get smarter by sharing knowledge with others. After that I would look at highly specialized complex fields with big problems to solve -- like genetic research or whatever those people are doing at CERN. After that, believe it or not, I would look in certain parts of law or the government -- but this is where we start to go around the bend.
As we know from the the comic books and Star Wars, the bad guys often have pretty well developed brains too. So anyone who is interested in competing to build their brain into the most powerful tool possible -- is also going to have to resist the call to the dark side -- lest they suffer the fate of Aniken Skywalker.
I have been fortunate to be around enough super big brained people to know that I don't have to keep the phone line open for the call from the people at CERN. I like a mental challenge, but I can't quite ever recount what the higgs boson is -- let alone how to find it. I do get a thrill from working close to super smart people and doing what I can to clear a path so the greatest minds can do the greatest things. There is no where that next illusive sub atomic particle will be able to hide from my daughers!