Adaptability Is Half the Answer
Every parent is told to raise an adaptable child. Adaptability on its own produces a person who can see what to do and cannot get it done. The second factor is the one nobody names, and a third one decides whether either gets used.
My children gave me their verdict on Bangalore after the first week of school. Too much traffic, nobody stays in the lane, Dubai was organised. They are right, and I did not tell them the other half. In Dubai somebody else is holding the steering. Here nobody holds it for them, and every junction has to be read rather than obeyed. A whole city reading each other at the same time looks like chaos from inside a car.
That is the moment this piece comes from, because it put a question in front of me that most parenting advice answers badly. If you cannot predict the working life your child will have, what exactly are you supposed to cultivate? The word handed to every parent right now is adaptability. It is the correct word and it is half an answer, and the missing half is the reason so many adaptable people never build anything.
The short version:
- Adaptability is real and it is incomplete. It tells you what to do in a situation nobody designed. It does not give you the capacity to carry it out.
- The second factor is energy conversion — how much a person can take in and turn into output. Our species did not win on cleverness alone. Pontzer and colleagues reported in Nature in 2016 that humans burn roughly 400 kcal a day more than chimpanzees and bonobos, 635 more than gorillas, and 820 more than orangutans at equivalent body size. We are the high-throughput ape.
- Childhood is an energy decision, not a waiting room. Kuzawa's team showed in PNAS in 2014 that a child's brain peaks at around age five consuming 43% of the body's daily energy and about two-thirds of its resting metabolism, and that body growth slows to pay for it.
- The dose matters more than the intensity. Antifragility is a real mechanism, and the evidence says the curve bends. Seery, Holman and Silver found in 2010 that some lifetime adversity predicted better outcomes than both none and a lot.
- Self-knowledge is the gate on both factors. In a 2025 study of 319 knowledge workers across 936 real tasks, confidence in the machine predicted less critical thinking while confidence in oneself predicted more. Knowing what you can actually do is what keeps the other two switched on.
The half that gets all the attention
The strongest scientific version of the adaptability claim is not a self-help idea. It belongs to Rick Potts at the Smithsonian, who named it variability selection in Evolutionary Anthropology in 1998: when a lineage is thrown across repeatedly different environments, selection stops rewarding fitness to any one of them and starts rewarding versatility itself. The capacity to handle a range becomes the trait. The sediment record at Olorgesailie supports it, with lake levels rising, falling and drying out again across the periods when the biggest changes in our lineage cluster. Potts and colleagues later put numbers to that instability in Science Advances.
Be careful with what that does and does not say. It does not say our ancestors were smarter and outcompeted everyone. That story is popular and thin. It says instability was the teacher and versatility was the syllabus.
So adaptability has real standing. My objection is not to the word. It is that a child raised on adaptability alone becomes a person who can read every junction in the city and has nothing in the tank to cross one.
The half nobody names
Here is where the popular account of human evolution is not just incomplete but actually wrong, and the correction is the most useful thing in this article.
For decades the explanation for our expensive brain was a trade. Aiello and Wheeler proposed in Current Anthropology in 1995 that we paid for brain tissue by shrinking gut tissue, one costly organ funding another. It is a satisfying story and it is repeated everywhere. Then in 2011 Navarrete, van Schaik and Isler surveyed 100 mammal species and found no such trade-off. What they found instead was a negative correlation between brain size and stored fat, which makes sense, because a big brain and a big fat reserve are two different bets against starvation. Pick one.
Humans broke that rule. We carry an unusually large brain and unusually high body fat, which by the mammal pattern should be impossible. Pontzer's work supplies the answer. We did not fund the brain by cutting something else. We raised total throughput. We became an animal that takes in and spends dramatically more energy than our closest relatives, and then spent the surplus on a brain, on fat, on faster reproduction, and on a childhood long enough to learn in.
That is a different kind of claim from the usual one, and it changes what capability means. Efficiency reallocates a fixed budget. Throughput enlarges it. I have argued elsewhere that efficiency is the prime mover behind our institutions, and I stand by it, with one correction this piece is here to make: efficiency alone is a fragile strategy. An efficient system with a fixed budget is optimised for the conditions it was tuned to, which is exactly what variability selection punishes. Throughput is what buys the room to be wrong.
Bring that down to a person and it stops being metaphor. Conversion is how much sleep, food, movement, attention and recovery a person turns into finished work. It is the reason two people with identical insight produce unequal amounts of it. Ideas are cheap to have and expensive to carry.
Childhood is where the two get built, and they are built physically
The Kuzawa finding deserves more weight than it gets. A five-year-old's brain is running at 43% of the body's entire daily energy draw, near two-thirds of resting metabolism, and the child's physical growth slows down while that is happening. The cost is not building the brain, which is mostly finished by then. The cost is maintaining the connections that learning requires.
Read that as an engineering decision our species already made. Childhood is the period where the body deliberately underinvests in getting bigger so it can overinvest in getting adaptable. Adaptability is not a personality trait that a child is lucky to have, and it is not only a matter of how a child perceives and updates. It is what the child's metabolism is spending its budget on, at a price the body agrees to pay.
Which means both halves are trainable in the same place. The stuff that raises conversion in a child is not mysterious and not new: sleep, food, and enough movement that the body's systems are actually loaded. Brussoni and colleagues reviewed 21 studies in 2015 on risky outdoor play and found positive effects across physical activity, social behaviour, injury and aggression. Children with more independent mobility were measurably more active. A child who is driven everywhere and supervised continuously is having both factors quietly withdrawn: less load on the body, and fewer situations that have to be read rather than followed.
The word Taleb gave us, and the dose it hides
Nassim Taleb's word for this is antifragile, and the definition in Antifragile (2012) is worth quoting exactly, because the word is abused constantly: "Antifragility is beyond resilience or robustness. The resilient resists shocks and stays the same; the antifragile gets better."
The distinction is right and it is not a motivational slogan. It describes real mechanisms, and it supplies the part the argument for a cognition gym left open: what the load actually does once it lands. A muscle loaded and recovered comes back stronger. A bone remodels along the lines of stress it receives. An immune system that meets dirt, microbes and other children develops differently from one that does not. In each case the system does not merely survive the stressor, it uses it.
Then comes the part that gets left out, and leaving it out is how a decent idea turns into something harmful when it reaches parenting. Every one of those mechanisms is dose-dependent. Load a muscle beyond recovery and it tears. The psychology matches. Seery, Holman and Silver tracked a national sample over several years and found a U-shaped relationship: people with some history of lifetime adversity reported lower distress, less functional impairment, fewer post-traumatic stress symptoms and higher life satisfaction than both people with a lot of it and people with none. They were also least shaken by new adverse events.
Some, not none, not a lot. That is the whole finding and it is the most important sentence a parent can hold.
So when I say the chaos of an unorganised city is an education, I am making a narrow claim, not a romantic one. Negotiating a junction is a dose. Being unsafe is not a dose, it is damage. The parent's job in this frame is not to remove difficulty and not to supply it, but to manage its size.
What decides whether either factor ever fires
A child can have both capacities and use neither, and this is where the third thing enters, the one I care about most as a parent and the one this whole argument turns on.
Adaptability requires knowing that your current read of the situation is a read and not the truth. Conversion requires knowing what you actually have in the tank today. Both of those are self-knowledge, and without it adaptability becomes reactivity and conversion becomes burnout.
The evidence for this used to be soft. It is not soft any more, because AI gave us a clean natural experiment in it. Lee and colleagues at Microsoft Research and Carnegie Mellon surveyed 319 knowledge workers about 936 real AI-assisted tasks and found the pattern that should reorganise how we think about this: higher confidence in the AI predicted less critical thinking, while higher confidence in one's own ability predicted more of it. Two people using the same tool on the same task diverge based on what they believe about themselves.
That is self-knowledge acting as a gate, measured, in the exact conditions our children are going to work in. A child who knows what he can do supervises the machine. A child who does not know hands over the steering, and the handover feels like competence the entire time.
Where this leaves a parent
Four things follow, and none of them require a curriculum.
Protect the load. Sleep, food and real physical loading are not adjacent to intelligence, they are the budget it runs on. A tired child is not a less motivated child, he is a child with less to convert.
Let situations stay unsolved in front of them. Every problem you resolve on your child's behalf is a junction he does not have to read. The dose is small and constant, not dramatic.
Manage the size of the difficulty, not its presence. Some, not none, not a lot. If you cannot tell which side of the curve you are on, ask whether the child recovers by the next day. Recovery is the test.
Make him check himself before he checks the answer. This is the one that matters most in the AI era, and it is the cheapest to practise. What do you think it is, before you ask. How sure are you, and why. Where would you be wrong. That habit is the gate, and the gate is what the research says decides everything downstream.
I did not move my children to a chaotic city for any of this. The lesson is arriving anyway, and my job is to keep the dose right and make sure they can see themselves clearly enough to use it. Adaptability was never the whole answer. It is what you do with the tank full and the mirror working.