One of the more vicious debates that has raged in psychology for over a century is this: What exactly is intelligence, and where does it come from?
Despite decades of symposia, meta-analyses, and ideological campaigns pitted against each other, we’re still no closer to fully unpacking Spearman’s g (a measure of general intelligence) or even agreeing on whether it’s a meaningful construct to begin with.
The truth I have to share isn’t a breakthrough that finally cracks the code. Instead, it’s a deeper, more transformative truth about IQ itself: Where intelligence comes from doesn’t matter nearly as much as what we do with the one we’ve got. And once we start deploying the concept of "effective IQ," it turns out we can do a lot more than simply philosophize about its origins.
In fact, science has shown again and again that we can either improve the output of the mental engine we’ve been handed, or we can grind its gears down to dust with habits that sabotage it.
And if you are anything like me, you will be far too familiar with the second category.
The Things We Do to Lower Our Effective IQ
You don’t need a neuroscientist to tell you that a foggy mind is often our very own doing.
The haze that follows a well-enjoyed bottle of wine, or the temporary dullness that we curse ourselves with thanks to four hours of sleep, won’t exactly put us in Nobel winner territory the next day.
We drink. We doom scroll. We sleep poorly. We put ourselves in environments that drain our attention and keep us reacting to stimuli instead of engaging in deep thinking. And then we wonder why our brain doesn’t show up when we need it most. It would, if we gave it a chance.
Even the world’s best engine needs a responsible driver, and a clear road to rev its engines on.
And here is where we fall into another trap of our own making. We often treat our mental performance like a taboo subject. Many people shy away from the topic of intelligence altogether, afraid their test score might become a verdict they’d rather not hear. Too many attach intrinsic value to a figure that is in itself meaningless, and only takes shape based on how we deploy our agency in using it. That avoidance costs us something real: We end up ignoring the habits that actually matter for our effective IQ more than the baseline score.
Think of the exploration loops Da Vinci learned in Verrocchio’s workshop, where he bounced between mediums, paused what didn’t work, reinforced what resonated. He was a genius, to be sure, but so were millions before who never painted even the side of a cave with their palmprints. Learning cannot happen without intention, and no one stumbles upon a higher level of performance by accident.
Another trap we fall into is one set out for us by the institutions that were supposed to do the opposite. Too often, people walk away from school convinced they’re not smart, when in reality, they were just in a system that didn’t bring out their best, at a time when their mental engines were yearning to feed on something entirely different from epistemological sustenance.
Challenging these deeply seated narratives can be hard, but they are worth the effort. Because even if you can’t swap out the hardware, you can always upgrade the software.
The Habits that Actually Help Make You Smarter
Remember, whether any of the habits below nudge Spearman’s g one inch up or down is beside the point. What matters is that research has shown that they measurably improve performance. And if you’re serious about performing better, you need to get just as serious about the habits that drive it.
First, we know that learning isn't a brute-force effort. It works best when we interleave what we're learning, mixing subjects and testing ourselves regularly. It’s more effortful, yes, but much like lifting weights, that struggle is what makes the brain grow.
And sorry, podcast junkies—recent research by Hui and Godfroid showed that reading beats listening for retention, which isn't all that surprising if you've followed the breadcrumbs of how ease in the process of learning often means a deficit in the results.
We also know that chunking helps us remember more, and that the memory palace method can turn almost anyone into a Roman orator, delivering entire speeches without a papyrus in sight. If these feats aren't effective IQ in action, I don't know what is.
To really hit home the brain-body duality, we also know that movement sharpens our cognition. Kim and colleagues weren't exactly burying the lede in their 2011 article "Exercise training increases size of hippocampus and improves memory," and numerous studies after theirs have shown how aerobic activity can improve executive function. In fact, in older adults, regular mobility is directly linked to better cognitive performance and lower risk of dementia.
If you're surprised, remember that our brains didn't evolve to operate in stillness. They evolved to think in motion, walking, navigating, reacting to the world around them. In fact, one of the most overlooked habits for improving cognitive performance is giving your brain the kind of environment it evolved for.
We didn’t get smart by sitting still or memorizing lists. We got smart by exploring the world, spotting patterns, making predictions, and adjusting course when we were wrong. That’s how our neural architecture was built by nature, through movement, curiosity, and conversation.
It's no wonder then that brains perform better when they’re engaged in real-time experiential learning, in the company of others. People who stay mentally sharp into old age aren’t the ones who passively consume what they're given; they’re the ones still asking questions about the world, expecting each answer to only beget another question.
What Really Matters About Intelligence
The truth about IQ is that the figure you got from WAIS or Stanford-Binet doesn't define you, and it never did. What matters is how well you drive the mind you’ve got, and how seriously you take the road ahead.
So, if you want to maintain your edge, seek out novelty. Debate your ideas. Explain something out loud. Step into unfamiliar territory—and remember to sleep well before you do. The brain rewards exploration and punishes stagnation.
And above all, remember that your effective intelligence isn’t fixed. It’s as responsive and powerful when correctly tuned as it is fragile if neglected.
As with most things in life, you’re bound to fall to the level of your habits. And the truth about IQ is that we have much more agency over how it manifests in our lives than most ever dare to imagine.
References
Hui, B., & Godfroid, A. (2025). Listening, reading, or both? Rethinking the comprehension benefits of reading‐while‐listening. Language Learning. Advance online publication.
Erickson, K. I., Voss, M. W., Prakash, R. S., Basak, C., Szabo, A., Chaddock, L., ... & Kramer, A. F. (2011).
Exercise training increases size of hippocampus and improves memory. Proceedings of the National Academy of Sciences, 108(7), 3017–3022.
Stine-Morrow, E. A. L., Parisi, J. M., Morrow, D. G., & Park, D. C. (2008). The effects of an engaged lifestyle on cognitive vitality: A field experiment. Psychology and Aging, 23(4), 778–786.
Fratiglioni, L., Paillard-Borg, S., & Winblad, B. (2004). An active and socially integrated lifestyle in late life might protect against dementia. The Lancet Neurology, 3(6), 343–353.
Grønkjaer M, Flensborg-Madsen T, Osler M, Sørensen HJ, Becker U, Mortensen EL. Intelligence test scores before and after alcohol-related disorders: a longitudinal study of Danish male conscripts. Alcoholism: Clinical and Experimental Research. 2019;43(10):2187–2195.
Samani J, Pan SC. Interleaved practice enhances memory and problem-solving ability in undergraduate physics. NPJ Science of Learning. 2021;6(1):32.
Qureshi A, Rizvi F, Syed A, Shahid A, Manzoor H. The method of loci as a mnemonic device to facilitate learning in endocrinology leads to improvement in student performance as measured by assessments. Advances in Physiology Education. 2014;38(2):140–144.
