Why do we find satisfaction in a well-organized toolbench, a clean piece of code, a direct route home? I think it comes from something more basic than culture: nature rewards the individuals, and the species, that operate more efficiently than their competitors. Any organism that fails to pursue efficiency gets outcompeted and replaced by ones that do — that’s just natural selection running its course. Intelligence doesn’t sit outside that rule. I think it’s one of the strategies life evolved for pursuing it: the capacity to calculate, in real time, which efficiencies are actually worth chasing.
The evidence: smarter brains do more with less
Your brain weighs about 2% of your body but burns roughly 20% of your total energy — evolution doesn’t carry that kind of overhead unless it pays for itself.
The clearest evidence that it does comes from what researchers call the “neural efficiency hypothesis.” A 2009 review in Neuroscience & Biobehavioral Reviews established the finding: when people with higher intelligence perform cognitive tasks, their brains show less activation than less-intelligent people doing the same task — not more power, less. A 2016 study in the Journal of Neuroscience found the same pattern at the network level: intelligent individuals reconfigure their neural circuits more sparsely, recruiting only what the task actually needs. A more intelligent brain isn’t a bigger engine solving the same problem. It’s solving it while spending less.
This is the part of the hypothesis with real data behind it, and it’s a genuinely useful reframe: intelligence, at the neural level, looks like getting the same output for less metabolic cost — not raw processing power, but processing discipline.
The refinement: efficiency without judgment fails
Here’s the part that keeps this from being a simple “efficient is smart” story. Daniel Kahneman’s Nobel Prize–winning work on bounded rationality showed that humans routinely default to “fast and wrong” heuristics — mental shortcuts that are efficient in the moment and produce systematic errors. Efficient thinking and correct thinking are not the same thing; a shortcut that saves effort can also be the shortcut that leads off a cliff.
That’s why I don’t think intelligence can just mean “minimize effort.” It has to include the judgment to tell those two kinds of shortcut apart — the one that reaches the goal faster, and the one that only feels like it does. An organism, or a person, that optimizes for the wrong thing efficiently isn’t intelligent. It’s just fast.
As a software engineer, the clearest way I have of thinking about this is the difference between a local minimum and a global minimum. Optimization that only ever moves downhill will happily settle into the first low point it finds and call it done — that’s a local minimum, and from inside it, it genuinely looks like the least possible effort, because any small move in any direction looks like more work. Reaching the global minimum — the actual least-effort solution — sometimes requires climbing back out of that comfortable low point first, which looks like wasted effort to anyone watching, and even feels that way while you’re doing it. I think that’s what a lot of “unnecessary-looking” effort actually is: not a failure to optimize, but a more intelligent search that’s willing to look less efficient in the short term because it’s already seen a lower point further out.
So intelligence is efficiency, plus judgment about which efficiency
Put together, that’s the actual claim: efficiency-seeking isn’t unique to intelligence — it’s the pressure every living thing is under. What intelligence adds is the capacity to correctly identify which efficiencies are worth pursuing, at the right time scale, instead of just grabbing the nearest shortcut. The neural efficiency research shows the mechanism (less activation, same or better output); Kahneman shows what happens when that mechanism runs without judgment attached.
The practical takeaway is less about individual habits and more about how to evaluate outcomes: an efficient-looking shortcut isn’t automatically an intelligent one, and a slower, more deliberate path isn’t automatically a wasteful one. The judgment behind the choice is the thing actually worth calling intelligence.
Sources & Further Reading
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The Neural Efficiency Hypothesis — Neuroscience & Biobehavioral Reviews (2009). Seminal review establishing that higher intelligence correlates with reduced brain activation during cognitive tasks. https://www.sciencedirect.com/science/article/abs/pii/S0149763409000591
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Higher Intelligence Is Associated with Less Task-Related Brain Network Reconfiguration — Journal of Neuroscience (2016). Brain imaging study showing intelligent individuals reconfigure neural networks more sparsely during problem-solving. https://www.jneurosci.org/content/36/33/8551
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Neuroenergetics and General Intelligence: A Systems Biology Perspective — NCBI PubMed Central (PMC7555089). Links brain energy metabolism to the g-factor, framing general intelligence as fundamentally rooted in metabolic optimization. https://pmc.ncbi.nlm.nih.gov/articles/PMC7555089/
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Thinking, Fast and Slow — Daniel Kahneman (Farrar, Straus and Giroux, 2011). The book-length treatment of System 1 / System 2 thinking and how efficient heuristics produce systematic errors. https://us.macmillan.com/books/9780374533557/thinkingfastandslow
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Daniel Kahneman, Nobel Lecture on bounded rationality (2002) — the earlier academic work the book builds on. https://www.nobelprize.org/prizes/economic-sciences/2002/kahneman/lecture/
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