All of the things mentioned above take much time and effort, and even then the gains can be fairly limited. The brain is complex and responsible for a ridiculous number of functions. As a result, it’s easy to increase ability in one region without affecting others. Musicians may have exemplary knowledge of how to read music, listen to cues, dissect sounds and so on, but this doesn’t mean they’ll be equally good at math or languages. Enhancing levels of general, fluid intelligence is difficult; it being produced by a range of brain regions and links means it’s an especially difficult thing to “increase” with restricted tasks or methods.
While the brain remains relatively plastic throughout life, much of its arrangement and structure is effectively “set.” The long white-matter tracts and pathways will have been laid down earlier in life, when development was still under way. By the time we hit our mid-twenties, our brains are essentially fully developed, and it’s fine-tuning from thereon in. This is the current consensus anyway. As such, the general view is that fluid intelligence is “fixed” in adults, and depends largely on genetic and developmental factors during our upbringing (including our parents’ attitudes, our social background and education).
This is a pessimistic conclusion for most people, especially those who want a quick fix, an easy answer, a short-cut to enhanced mental abilities. The science of the brain doesn’t allow for such things. Sadly but inevitably, there are many people out there who offer them anyway.
Countless companies now sell “brain-training” games and exercises, which claim to be able to boost intelligence. These are invariably puzzles and challenges of varying difficulty, and it’s true that if you play them often enough you will get increasingly better at them. But only them. There is, at present, no accepted evidence that any of these products cause an increase in general intelligence; they just cause you to become good at a specific game, and the brain is easily complex enough not to have to enhance everything else to allow this to happen.
Some people, particularly students, have started taking pharmaceuticals such as Ritalin and Adderall, intended to treat conditions like ADHD, when studying for exams, in order to boost concentration and focus. While they might achieve this briefly and in very limited ways, the long-term consequences of taking powerful brain-altering drugs when you don’t have the underlying issue they’re meant to treat are potentially very worrying. Plus, they can backfire: unnaturally ramping up your focus and concentration with drugs can prove exhausting and depleting to your reserves, meaning you burn out much faster and (for example) sleep through the exam you’re studying for.
Drugs meant to improve or enhance mental function are classed as Nootropics, aka “smart drugs.” Most of these are relatively new and affect only specific processes such as memory or attention, so their long-term effects on general intelligence are currently anyone’s guess. The more powerful ones are restricted largely to use in neurodegenerative diseases such as Alzheimer’s, where the brain is genuinely degrading at an alarming rate.
There is also a wide variety of foods (for instance, fish oils) that are supposed to increase general intelligence, too, but this is also dubious. They may facilitate one aspect of the brain in one minor way, but this isn’t enough for a permanent and widespread boost of intelligence.
There are even technological methods being touted these days, particularly with a technique known as transcranial direct-current stimulation (tCDS). A review by Djamila Bennabi and her colleagues in 2014 found that tCDS (where a low-level current is passed through targeted brain regions) does seemingly enhance abilities such as memory and language in both healthy and mentally ill subjects, and seems to have few to no side-effects thus far. Other reviews and studies have yet to establish a viable effect of the method though. Clearly, there’s a lot of work to be done before this sort of thing becomes widely available therapeutically.11
Despite this, many companies currently sell gadgets that claim to exploit tCDS for improving performance on things like video games. To avoid libeling anyone, I’m not saying these things don’t work, but if they do, that means companies are selling items that actively alter brain activity (as powerful drugs do) via means that aren’t scientifically established or understood, to people without any specialist training or supervision. This is a bit like selling antidepressants at the supermarket, next to the chocolate bars and packs of batteries.
So, yes, you can increase your intelligence, but it takes a lot of time and effort over prolonged periods, and you can’t just do things you’re already good at and/or know. If you get really good at something then your brain becomes so efficient at it, it essentially stops realizing it’s happening. And if it doesn’t know it’s happening, it won’t adapt or respond to it, so you get a self-limiting effect.
The main problem seems to be that, if you want to be more intelligent, you have to be very determined or very smart in order to outsmart your own brain.
You’re pretty smart for a small person
(Why tall people are smarter and the heritability of intelligence)
Tall people are smarter than shorter people. It’s true. This is a fact that many find surprising, even offensive (if they’re short). Surely, it’s ridiculous to say that someone’s height is related to their intelligence? Apparently, it isn’t.
Before I get besieged by an enraged but diminutive mob, it’s important to point out that this is not an absolute by any means. Basketball players are not automatically more intelligent than jockeys. André the Giant was not smarter than Einstein. Marie Curie would not have been outwitted by Hagrid. The correlation between height and intelligence is usually cited as being about 0.2, meaning height and intelligence seem to be associated in only 1 in 5 people.
Plus, it doesn’t make a big difference. Take a random tall person and a random short person and measure their IQs; it’s anyone’s guess as to who’ll be the more intelligent. But you do this often enough, say with 10,000 tall people and 10,000 short people, and the overall pattern will be that the average IQ score of taller people will be slightly higher than that of the shorter people. Might be just 3–4 IQ points’ difference, but it’s still a pattern, one persistent across numerous studies into the phenomenon.12 What’s going on there? Why would being taller make you more intelligent? It’s one of the weird and confusing properties of human intelligence.