A classic quant interview question goes, "what's the expected value of cards you need to draw from a deck of 52 before you draw an ace?". You have two minutes. This is a hard problem.
I naively tried to solve this by trying to work out the probability you draw an ace as the first card, which is 4/52 and an ace as the second card which is 48/52 times 4/51 etc. etc. But I eventually realised that to get from this to the "expected value" (which means the average number of cards if I'd need to draw if I repeated this experiment say hundreds of millions of times), I'd need to do this chain of probability for all 49 configurations (up until the only cards left are aces) in the worst case, sum them all up weighting each card by its probability... it gets ugly real fast. The sketch of the elegant solution is that the 4 aces divide the deck up into 5 sections, and so in the average case, you draw 48/5 = 9.6 cards.
With my two nerd friends, we discussed this quant interview question and how we all had no chance of solving it without specialised preparation and training. Then we memed for hours where any kind of mistake or delay means you are "not a quant". Can't figure out the rules of the board game? Not a quant. Forgot to water your plants? Not a quant.
Intelligence is an uncomfortable topic to talk about. It's very personal and the truth is a bit hard to swallow. I'm going to present evidence for how intelligence actually works and argue why intelligence matters less than you think.
You are born with your intelligence as an attribute much like your height. It's mostly genetic with some effects from nutrition, education and general support. People don't like to hear this because it's offensive. It's not fair right? How can some people be born more stupid than others, but that's just how it works. This is a well studied attribute of people in the field of psychology. Intelligence can broadly be defined as the performance of the brain to perform tasks well. It's like the mental version of physical fitness. As such, it's actually a very broad spectrum of skills and encompasses things all the way from auditory intelligence to 3D comprehension to good old logical puzzles like the one above.
Psychologists have discovered a pretty strong evidence of a G factor, which is a general intelligence score. The higher the G factor, the higher your specific specialised intelligence scores tend to be, for instance your pattern recognition or your memorisation. One strong proxy for your general intelligence is how many digits can you memorise in one go from a sequence? The higher the G factor, the wider the gap tends to be for all your specialised intelligence scores, for instance your verbal intelligence can be a lot higher than your creative problem solving. There are some theories on specific branches of types of intelligence but they are statistical models derived from correlated task performance and we have relatively poor understanding of mechanisms of how they actually differ and why this is.
There is also the concept of fluid intelligence vs crystallised intelligence. Fluid intelligence is no-context problem solving and ability to adapt and learn. So this is your quant interviews, logic puzzles and IQ tests. This grows as you age and plateaus in your adulthood and slowly declines as you age. Crystallised intelligence is the knowledge and wisdom you accrue as you age and learn. For instance, a PhD can rant for days on fluid dynamics or a coin collector can immediately value a coin from his vast internal knowledge base. This grows over time indefinitely if you keep learning and exercising your mind. Evaluating fluid intelligence is hard because it's often contaminated by crystallised intelligence. For instance if I was trained in statistics, that quant question might be very easy for me as my years of memorised solutions and pattern recognition can be applied to solve the problem. In practice this is also the practical pattern to solving real problems, as real world mathematicians draw upon their vast reserve of knowledge and their naturally high fluid intelligence and talent. Some people are freaks of nature, for example nobody taught Gauss that instead of brute forcing 1+2...+100, you can just group the numbers and just multiply (101 times 50). Gauss definitely could've been a quant XD.
Generally intelligence follows the bell curve distribution (it strikes again), just like height. So if you sample from a large enough population, you'll find most people are average, some are in the long tails of medical retardation and some are just geniuses. Generally bell curve distributions are a result of a lot of random variables either increasing or decreasing intelligence interacting with each other randomly in the population as people mate. For instance, faster reaction times and neuron activations tend to correlate with higher intelligence. There are measured statistically significant differences in intelligence between cultures. This however is weak evidence for "superior" or "inferior" races as crystallised intelligence, cultural differences, and measurement techniques tend to contaminate the results. For instance the height of the Chinese population has increased by multiple centimetres. Obvious the whole country did not evolve in two generations. Nutrition and access to healthcare has allowed latent genes to be healthily expressed. Similar effects apply to intelligence.
So, what to do with all this information? I'd argue don't stress about it. You should definitely exercise your brain just as you'd exercise your body. I know I'm not physically gifted enough to sprint faster than Usain Bolt, but it doesn't mean that running is not beneficial to my health or other aspects of my life. Your crystallised intelligence can prove critical in your life trajectory. I remember reading the introduction of a Dr Karl book where he candidly confessed that he only has a very average fluid intelligence, but his vast reserve of accumulated crystallised intelligence just hit a point where he just began understanding things". Keep your mind and your body well nourished, exercised and sharp. It will probably make you a lot happier too.
Intelligence is also kind of overrated. It's a tool to achieve outcomes and is of course a useful tool for problem solving, but the world is filled with people using their intelligence to screw other people over. You do not need to have 200+ IQ to do things in life. How you treat other people, your communication skills, your dedication and commitment. There are so many things that can make your life meaningful and lead to successful outcomes beyond any intelligence a test can measure. For example, people like Bill Gates or Elon Musk are actually not that smart, certainly not as smart as most maths professors. In fact, Richard Branson has ADHD and dyslexia. I'm using famous, rich people as an example because they are the stereotype of geniuses in our society but they mostly got their with great business skills and ability to lead, pitch or rally people up.
I would also argue wisdom, is far, far more important than short term problem solving. Life is long. Far longer than any two minute interview. If you make the right choices in life for you, you will get far outsized returns in whether you become the person you want to be. Your impact on the world and the people around you will also be far more positive than any smart, short sighted person can ever achieve.
So chin up, play the hand that you are dealt, it may not always be four aces but it might just be the cards you needed.