When I look at this article and ask "What is the strongest counter-example that comes into my head", and I think something like "Being a mathematician or physicist". I think I have the g-factor to get a math degree if I really wanted, but it's not at all clear how I could reach the level of a working mathematician in six months, despite already being a decent programmer. There are a few replies my inner Habryka might say, and I'm curious if any of them seem accurate, and if some are very much not what you intended to say:
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This advice isn't meant for everyone. In the same way that I'm expecting people to be 140+ IQ to use this advice, I also expect them to be at least +2.5 SD of conscientiousness. If you can put in 60+ hours a week of high quality mental work into this task, you actually could achieve this - most students of mathematics do a fraction of this time. You underestimate how much progress can be made with real focus and drive paired with strong conscientiousness and smarts - it's a multiplicative effect that adds up very quickly. Such a person really could get to that level in six months, but they're rare enough that standard career paths can't accommodate them, which is why society needs specialists in the first place.
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When you imagine being a working mathematician, you imagine having many years of schooling that teaches you about a very broad variety of maths. This is not what I am imagining - I am imagining having the level of ability to perform a specific type of job a mathematician might do. For example, take this SLT theorist job by Timaeus. https://timaeus.co/blog/updates/2026-04-09-hiring This doesn't require you to know everything an undergraduate maths degree holds. It requires you to know an important subset and to grasp some universal skills like writing rigorous proofs and doing mathematical research at all. Rolling your own curriculum could get you there in 6 months. Think about your own CS career - does someone need to have learned everything you learned in order to do what you do? Clearly not - if they'd aimed at your specific target from the start, they'd get there in six months.
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The kind of person who would be an actual research-grade mathematician really is a level of expertise beyond this post. It's a level beyond, say, a solid mid-level programmer in their field, and to get to that level it really does take years even if you're good. It would take months to get to the level of doing an easier class of problems that people would still pay you for, and that's the level I would expect a Lightcone-level generalist to be able to get to in a different area in the same domain within six months.
Or it could be something else entirely.
1It's IMO a mixture of 1 and 3.
My current belief is that people around 2-3 SDs above average can learn everything in an undergraduate degree at a top university in around 6-9 months, if they actually spend all their time doing focused study (I remember there was a guy with the last name "Young" whose full name I don't quite remember who did this for an MIT undergraduate education and wrote a blog about it).
And then, I do think as things go, being a research-grade mathematician is playing on one of the hardest difficulties available. That said, I remember Aubre De Gray, anti-aging guy not generally widely known for his math research, actually made a pretty serious contribution a few years back, and that felt like a good validation of a generalist world theory: https://www.quantamagazine.org/decades-old-graph-problem-yields-to-amateur-mathematician-20180417/
1For the benefit of later readers, this was Scott Young's MIT challenge, doing a full CS degree in 12 months. I saw this as rather incredible the first time I saw it, but maybe the more incredible thing was having both the circumstances and the agency to attempt it in the first place. https://www.scotthyoung.com/blog/myprojects/mit-challenge-2/
Yep, that's it! I really love that he did that. I remembered 6-9 months because he did it in just under 12, and also didn't do it full-time for something like the second half of it. But seems like it took a bit longer.
While still significant and hard, my intuition is that a problem 'of that shape' requires less front loaded theory. (while still being very smarts and math skill heavy!)
i feel like i kind of expect "research" to be potentially separate from these? eg you can have very very technical people without good technical research taste, and i think probably the same on a lot of design type skills / research?
Research is mostly design! This is one of the big mistakes that people make IMO! Almost all of high-quality research is ontologizing new domains and thinking really hard about what are good new abstractions to think in within this domain, and that's the very central design skill!
One of the reasons why research is hard is because you need design, and usually you have technical prerequisites.
Having worked with experts across many industries, and having dabbled in the literature around skill transfer and training, there seems to be little difference within an industry between someone four years in and someone twenty years in, once you control for intelligence and conscientiousness.
I basically agree with the post, but I think you're underestimating the value of experience. It's true that there's not that much value in doing the same thing for 20 years, but if a person is learning different things, 20 years of experience means that they've had the necessary 3 months of ramp-up time for 80+ different subskills. Plus the more sub-skills you've ramped up on, the easier the remaining skills are. Learning one programming language take months but learning your 20th takes hours[1]. And people with experience can know about problems you don't know you need to ramp up on.
Already knowing things is overvalued by some hiring processes, but I think you're going too far the other way by discounting it entirely.
- ^
Both programming ramp-up times are to reach the ability to write code that does what you want in that language. Becoming an actual expert on the best practices for a language takes longer.
Experience is definitely worth quite a lot! And this matters for hiring.
But for any given expert you are going to hire (like an architect, or a biologist, or a specialized programmer), you probably won't actually benefit from their diversity of experience that much, because the breadth of skills they learned aren't that likely to actually be useful on the job most of the time. In law, for example, you have tons of legal specializations, and almost always when you want a lawyer, you will need their expertise in maybe 1-2 of those specializations, not all of them.
Plus the more sub-skills you've ramped up on, the easier the remaining skills are
I agree, that's non-trivially what this post is about!
Already knowing things is overvalued by some hiring processes, but I think you're going too far the other way by discounting it entirely.
I am a bit confused. I feel like hiring wise, this post is really very substantially about experience. I am saying that if I am hiring someone for a management position, I need them to have experience managing, otherwise training them on the job will be extremely costly. Similarly if I need someone to eventually learn programming, they better have some technical background. Indeed this post is about the limits of the generalist framework that I've found.
I feel like hiring wise, this post is really very substantially about experience.
I think that wasn’t that clear from the post. I read it as saying that you can have a talent for each of the 4 skills, and that experience with each skill isn’t transferable. Past experience in a skill is only relevant as a proof that you have a talent for that category.
I really like this article, and it feels very empowering and exciting. It's spawned a ton of thoughts, hence leaving two comments. It's also quite relevant to me - I've recently been asking myself, based on a job offer I'm expecting, how hard would it be for me to become an expert in compute governance? And I actually did think before reading this article that six months of dedicated full-time work could get me there, but I was thinking in a narrower domain than "all technical skills".
I'm very intrigued about the idea of there being a finite number of domains that I could learn and then be able to train myself to do any one item from like 90% of all things - one of my not-so-secret dreams in life is to be the kind of person that refutes the Character Sheet Hypothesis, the idea that if you're good at one thing (e.g, smart) you must be worse at some other thing. (e.g, strong, or charismatic)
That said, there are some skills you mentioned as both being in the design domain that feel very different. I've always thought of myself as inherently not good at several of those design-shaped skills - but I can write and design software, so according to this model, not only is this false, I already have a lot of the necessary foundations.
So I feel like I can write decently well and architect a software program, but I imagine myself totally bouncing off interior design / UI designs - it's not clear to me how to get started or how the skills transfer. I don't consider my writing to use the same skills that I imagine interior design / UI needs - this combination of visual creativity + aesthetic maturity to generate designs and the aesthetic taste to judge them. I envision my writing and system design as much more like a technical problem - what are the requirements I need from this piece of work and how can I create a system that achieves them.
It might be the case that I could treat internal design this same way, but I do not know how. If I were one of your employees, and you knew I could write well and perform systems architecture, so I had this design capacity, but you now needed me to design rooms at Lightcone, how would you tell me to utilise my existing design skills to more swiftly learn this new one?
So I feel like I can write decently well and architect a software program, but I imagine myself totally bouncing off interior design / UI designs - it's not clear to me how to get started or how the skills transfer.
You would not be the first person I've worked with who said this, who ended up making a lot of progress here.
IMO people overestimate the aspect of design that is about pixel-pushing, and underestimate the aspect of design that is about "in what order and with what priority do I need to show the user this information?". If you can answer that question, getting from there to a clean design is often not that hard (and then yes, you will have to spend at least a few weeks getting good at pixel pushing, but I doubt it's going to be the blocker).
People also drastically overestimate how helpful something like drawing or artistic skill is for design work. I think I am a pretty good designer but I am absolutely atrocious at drawing anything, and my artistic composition abilities are very weak.
Okay, I think I understand this now. For the benefit of other people with Jay-shaped problems in this area, I'll write down what I've learned:
If I were to design a CRUD app, I would immediately begin decomposing the problem into the basic language of the specific domain of web applications. We need a front-end, a back-end, and a database. We need to connect them up in some way. We need to host the application somewhere. Okay, I know what parts are needed.
Now, what is the specific problem I want to solve with this CRUD app? What differentiates it from any generic CRUD app? What information do I need to show to the user and how in order to ensure they can easily do whatever they will want to do with this app? Now I am in "core design skills" land. However, I had to go through that first paragraph to do so, I couldn't just start here.
So, it feels like I know nothing about interior design, not because I am bad at every step of interior design but because I am bad at the very first step - I cannot yet break down room design into the various components like lighting, furniture, color schemes, and so on that are required. (Honestly, even being able to write that previous sentence with specific examples indicates that I am less clueless than I originally thought of myself as) Since that's the first step to solving the problem, all the important skills I have that would actually help with this problem are hidden behind the relatively simple ones I lack.
If I've got that right, that is a very powerful and new way of looking at things for me! I wouldn't be surprised if this turns out to be one of the most valuable posts I see this year. It reminds me of when I first picked up an economics textbook - a bunch of things I didn't understand but were scary black boxes transformed into things where I knew how I could grow to understand them if I wanted.
1there seems to be little difference within an industry between someone four years in and someone twenty years in, once you control for intelligence and conscientiousness.
Well, four years is a pretty long time—from the start of that paragraph I wouldn't have assumed this is what you meant, because by itself this would actually make it hard to run a generalist-only operation
Ah, this was just supposed to establish the general point that intelligence tends to dominate performance and that performance levels of relatively quickly. Almost no one who got into a profession actually tried learning things at close to their maximum speed.
I then think if you do that, you can get that number to something more like 6 months until you are comparably good (you will lack some breath, but will be similarly good as professionals at any narrower skill you were trying to learn), and 12 months until you have a shot at being in the top performers of the domain.
In my experience in the technical domain (read: observing fellow college students), it seems like people need a bit of that generalist energy in them to reliably be the sort that can go between domains. I'm unsure if this is just purely g factor.
I suspect similar is true for every other domain you listed except possibly management and physical (which seem more unified).
I really like the post though - I have definitely felt this way about technical skills, had sorta intuited management and physical, but hadn't seen this cross transfer design stuff.
Oh yeah, being willing to learn new skills is rare! It's definitely not just g. My guess is it's substantially cultural and can be transmitted, but it's definitely not the default.
Jimi Hendrix revolutionized guitar playing.
He died from overdose at 27. Perhaps practicing for 8 hours a day wasn't so good for his psyche?
Also, 2-10% of pro musicians get focal dystonia (a neurological condition where their muscles malfunction when they start doing their thing with their instrument), probably from playing too much. For example, the famous bassist Victor Wooten got it.
Also, I read about a famous trumpet player, maybe Louis Armstrong, and he had serious problems with his lips from playing really hard and playing a lot. He had to use a razor to cut scar tissue from his lips every day before concert to keep playing.
Also, maybe it's possible for these weirdos (not in a bad sense) but not for a typical human, even a very smart human. At least I don't find it possible for myself. I get tired, my muscles get tired, my ears get tired, my brain gets tired.
Also, novices at an instrument will have even more problems with unadjusted muscles and thus risk of overuse trauma, etc.
Counterexample: you cannot become an expert in playing any musical instrument in 6 months. (unless you're a freaking genius)
Huh, that seems false to me? My sense is musicians routinely get to very high levels of skill in a new instrument quickly, if they have already mastered at least one instrument before (like enough to play in a band professionally in a new instrument).
6 months of practice is a long time!
I actually had a conversation about this exact thing with Ben (who plays guitar at an approximately professional level). I think our conversation landed on 6 months being roughly reasonable (but things would end up a bit rough because your physical muscles end up exhausted and we had some uncertainty on whether you could make up enough of the calendar time during which your muscles are recovering via learning other things, but you could definitely do it if you spread out those 6 months over a year).
Is this a distinction between expert and professional? For many fields, a merely professional level is way below an expert level, and for others that difference may just be less legible.
In my own case I saw your tweet and my thought was that a fifth skill is the "aura" of a notable politician or someone with a cult of personality, but it's true that a merely "professional" politicians like a state assemblyman or city councilman may not have the same level of unreachable skills at all.
Is this a distinction between expert and professional? For many fields, a merely professional level is way below an expert level, and for others that difference may just be less legible.
Oh, I wasn't super planning to make a strong distinction here. My current belief here is something like: If you have achieved expert level performance (as you define here) at one task then you can reach expert level performance in 6 months at another task in the same domain. If you've only achieved professional-level performance, then you can reach professional-level performance in a bit less than 6 months (but not much less)
But don't expect pushing the frontier of that skill category to be as fast as learning a new task to the level you've already achieved somewhere else!
And then, to be clear, these things are very intelligence loaded. If you are in a domain that is so competitive that the experts are 4 SDs above average in intelligence, then don't expect you can get there if you are not at least that smart! I am not saying there is a magic "become expert in any domain independently of your intelligence" button, merely that skill acquisition doesn't take that long if you have learned related skills.
My sense is musicians routinely get to very high levels of skill in a new instrument quickly, if they have already mastered a bunch of instruments before (like enough to play in a band professionally in a new instrument).
I agree with the rest of your comment (6 months is a long time!) but this part seems to be moving the goal posts. A professional musician being able to learn an additional instrument quickly is not evidence that a non-musician designer[1] can.
- ^
Or is musician a subclass of athlete?
Playing an instrument is definitely a physical skill! (In my model, whose epistemic status, to be clear is "schizo galaxy-brain model")
Also, unfortunately I do think skills in the physical domain transfers somewhat less than in other domains (though my guess is still a decent amount, even between something like hockey and playing guitar). It's not the domain I care the most about, so I didn't go into details but clearly there is some muscle memory that will be kind of tricky to transfer (but again, I do actually expect really quite a bit of transfer).
There also a very important mental skill too. It's not just learning to move your muscles precisely, correctly and in time. It's also learning to hear and understand what you hear, to quickly identify what notes/chords/scales you're hearing, what comes next, quickly generating a potentially good sounding melody and quickly understandibg of what notes it consists, what techniques need to be used to play it, where all its notes are on your instrument. Although this latter part probably cross-trains very very well between different instruments, but for a non-musician I expect it cannot be learned in 6 months.
Oh, but then you're making a 5th category for "everything music related" :)
Ok, MAYBE someone who has already become an expert in a musical instrument and in music in general can become an expert in another musical instrument in 6 months if studying that full time, but am not at all sure about this.
So far I've been learning one musical instrument for 3 years, another for a year and another for a year. And I quite far from becoming an expert in any of them. Also, I doubt that you can productively practice it full time or even 4-5 hours a day because in my experience more practice per day gives diminishing returns - whether it's because of muscles getting tired or because of brain capacity or because of boredom I don't know.
Well, ok what I am sure of if that you have no experience in music, then becoming an expert in 6 months in any single instrument is impossible unless you're born as a genius. This is how it is in my experience and this is what observe among musicians around me - nobody gets good quickly.
Oh, but then you're making a 5th category for "everything music related" :)
I think the greatest skill transfer to music will be expert level performance at any other physical skill, but as I say here, I do think muscle memory is going to transfer less well than other things.
So far I've been learning one musical instrument for 3 years, another for a year and another for a year. And I quite far from becoming an expert in any of them.
I would be very surprised if you are anywhere close to 6 months of full-time deliberate practice in those 3 years? Also, do you have expert level performance in any other physical skill?
Also, do you have expert level performance in any other physical skill?
Nope
I would be very surprised if you are anywhere close to 6 months of full-time deliberate practice in those 3 years?
So, a year has 255 working days. So half a year is 255/2 times 8 = 1020 hours of working time if we assume 8 hours per day. Yes, I probably do have approximately that amount of practice under my belt, maybe a little more. Also I'm not sure that 8 hours of deliberate practice per day for half a year in music learning is possible and is good for you.
So, a year has 255 working days. So half a year is 255/2 times 8 = 1020 hours of working time if we assume 8 hours per day. Yes, I probably do have approximately that amount of practice under my belt, maybe a little more. Also I'm not sure that 8 hours of deliberate practice per day for half a year in music learning is possible and is good for you.
A year has at least 300 working days, and a day has at least 10 working hours (more like 11), at the time investment level I am talking about here. The 6 months is meant as a lower bound if you tried really hard, not as the thing that you would get if you worked a normal 9-5 and took two weekend days on this. So the right number I was anchoring on is more like 1800.
Oh, god, sorry, I also just remembered. You might be thinking of "professional level" or "expert level" as the kind of absurd thing that people aspire to when they want to be orchestral musicians. Like, get a job for nothing else but their musical skill.
I think in the case of musical instruments the skill thresholds are much much higher than I was thinking here.
Because there are so few jobs for being a professional concert musicians, I think the lengths people have to go to to reach that level are much higher than what I meant here for "professional". Like, I was thinking of the level of "professional" as "went to a top university for an undergraduate degree in a specialization and then ~2 years of work experience" not what I think is standard for professional music careers, which I think tends to be "start at the age of 5, practice as a half-time job almost all the way through your teens, and engage in deliberate practice all-throughout, then transition to full-time in your early 20s, all-throughout with extreme training regimes".
I don't actually quite know how this world works, but my model is definitely because supply for full-time musicians so vastly outstrips demand, that the competition here is much harsher, and the usual terms will be confusing.
Then my model definitely doesn't predict you would reach expert-level performance in 6 months of deliberate practice! That's like the whole point of the model!
1
1By "cannot ... any" do you mean "there are no instruments you can" or "there are instruments you cannot"? The former seems completely wrong to me, you definitely can become an expert in playing the kazoo or the triangle in 6 months. (Even if you mean the latter, I think there are very few instruments you can't become an expert in in 6 months, if you have no other job and no children and can spend 80 hours a week on it.)
I mean for most instruments you cannot, with exceptions like the triangle. About kazoo - isn't basically vocals with an extra sound effect? So its difficulty would be bounder from below by the difficulty of learning to sing.
You could totally learn to play a brass instrument in 6 months if it was your full-time job. I'm less sure you could competently play violin in that time period, although 6 months is a lot of practice time if it's actually your main priority.
Immediate taxonomy of subskills that came to mind:
- designing for consumers vs designing for producers
- technical breadth vs technical depth
- managing up vs managing down
- Physical strength vs physical dexterity
Dang it, now I wanna read/write posts for all of these
Epistemic status: Completely schizo galaxy-brained theory
Lightcone[1] operates on a "generalist" philosophy. Most of our full-time staff have the title "generalist", and in any given year they work on a wide variety of tasks — from software development on the LessWrong codebase to fixing an overflowing toilet at Lighthaven, our 30,000 sq. ft. campus.
One of our core rules is that you should not delegate a task you don't know how to perform yourself. This is a very intense rule and has lots of implications about how we operate, so I've spent a lot of time watching people learn things they didn't previously know how to do.
My overall observation (and why we have the rule) is that smart people can learn almost anything. Across a wide range of tasks, most of the variance in performance is explained by general intelligence (foremost) and conscientiousness (secondmost), not expertise. Of course, if you compare yourself to someone who's done a task thousands of times you'll lag behind for a while — but people plateau surprisingly quickly. Having worked with experts across many industries, and having dabbled in the literature around skill transfer and training, there seems to be little difference within an industry between someone four years in and someone twenty years in, once you control for intelligence and conscientiousness.
But sometimes someone on my team does actually truly struggle to get better at a task, even if they are smart. Or I notice that if I were to try to get them to do something, they would have no idea how to even get started unless they spent at the very least multiple months, if not multiple years, acquiring the foundations necessary to do so.
So the question becomes: What determines whether someone is capable of relatively quickly acquiring expert-level performance in domains ranging from preparing a legal defense, to preparing an architectural plan, to physically renovating a bathroom, to programming a conference schedule app?
And my current, schizo galaxy-brained theory is that there are exactly 4 skills:
If you are good at any task in any of those categories, you can become expert-level within 6 months at any other task in the same category.
Now why these exact 4 skills?
IDK, it kind of fits the data I've observed. But here is roughly how I came to believe what I believe:
First: across all tasks, performance correlates highly with general intelligence, and this dominates everything else. But clearly there's non-trivial variance left after controlling for it.
Then, there's an obvious divide between STEM and the humanities. Ask someone with a legal, history, or non-analytic-philosophy background to learn programming and mostly they bounce off or expect a multi-year training journey. Ask someone with a STEM degree to learn programming and it goes pretty well even if they've never programmed before.
Similarly, when I talk to people with a legal or humanities background and ask them about complicated frontend design decisions, they usually give surprisingly good input! They will pretty quickly jump into the fray of trying to model the user, figure out what a good product or information ontology, and have a sense of style about its presentation.
So that's it. There are exactly two skills. "Technical skills" and "Design Skills".
Then I tried to manage people. That... didn't go so well. Not only that, when I tried to get people on my team to manage other people, they also sucked at it!
So I learned that if I want to predict who will be good at management, I need to pay attention to whether they've managed other people before, and expect many months of practice until they are decent at it. Maybe it's a completely new cognitive domain, maybe it's just a domain where skill transfer is very hard and feedback loops are very slow and so it just takes everyone a while to learn the basic lessons, but nevertheless, if I want to predict performance at Lightcone, I gotta model people's management skills separately.
And then I tried to renovate a hotel.
And while the people on my team really ended up surprisingly good at a very wide range of tasks associated with construction and construction management, it also became clear that no one on my team would be able to perform the actual labor that our general contractors were able to perform. And also that they would totally smoke us in any sports competition. And that if I wanted to get someone on my team involved in the daily construction work, I sure expect that they would need many months of getting into shape and developing the right kind of physical skills.
So 4 skills it is.
Now, am I confident I have seen all skills there are in the world, such that no additional cluster will arise? Actually, yeah, kind of.
I have been walking through the world trying to keep track of what kind of career many of my acquaintances and colleagues go into for something like the last 2-3 years, and haven't really noticed any big holes. I have also been actively trying to think about careers that currently seem off limits to someone who has basic expertise in these 4 skill domains, and I have so far not been able to find something. My guess is if there is something I am missing it will be in something less career oriented.[2]
Need someone to build a script that automates filling out some business forms?
Give your econ masters student 3 months to learn programming and he can do it.
Need someone to drive your marketing push?
Give your interior designer 2 months to figure it out.
Need someone to head your internal legal department, double check the work of your lawyers, and prepare your legal defense in a high stakes trial?
Give your very smart frontend designer 3 months and they will go toe-to-toe with your lawyers.
Want to promote an engineer who has never managed anyone before to a manager?
Well, you better strap in for a year or more of pain while they acquire this completely new skill domain and traumatize all your new interns while doing so.
Want to get your backend engineer who is not good at writing, and is not good at interior design, to start taking more charge over your frontend?
Expect them to suck for at least a year until they can start competing with the smart designers on your team.
Want to get your quant finance guy who has never worked on a big codebase to start writing maintainable code and make nice clean Pull Requests?
Well tough luck, predict many months of telling them that yes, it is actually important that anyone can read your code and figure out how to modify these abstractions you've created.
Want to get your philosophy grad student dropout who has never done physical labor in his life to start managing construction projects and get their hands dirty?
Expect at least a year of getting into shape and used to the work, if they don't bounce off completely (though many subtasks of construction can be done with pretty little physical alacrity).
Give it a try yourself!
(Unhappy with any of my classifications? Fight me in the comments!)
Is there any externally validated or scientific basis for any of this?
Yes! It's not like, total consensus in the field of psychometrics, but task performance being extremely g-loaded across a wide variety of tasks is very well supported. People can really learn a very wide range of skills if they are smart.
And then within intelligence, math tilt and verbal tilt tend to be commonly used abstractions in psychometric testing that are predictive of success in careers in STEM or humanities.[3] Math fits nicely onto the technical domain. Verbal fits nicely onto the design domain.
A generalized "physical skill" factor is also well-supported. First, enough high profile athletes have switched from being world class in one sport to being world class in another sport such that there must be substantial skill transfer for these domains to explain that outlier success.[4] Second, somewhat unsurprisingly, if you measure people's sports skill you will find a strong "General Motor Ability" factor that explains performance across a wide range of motor skills.[5]
On management? IDK, that one I haven't seen much support for, but it sure matches my experience. There is an emotional intelligence literature, but that construct adds extremely little on top of just general intelligence. My guess is it's just a task that's very important and has terrible feedback loops, so everyone needs to fail for a while before they get good at it, but who knows.
Design. Technical. Management. Physical skills. Long ago, the four nations lived together in harmony. Then, everything changed when the Management Nation attacked. Only the True Generalist, master of all four elements, could stop them, but when the world needed him most, he vanished.
the organization I run, and which runs the website you're reading
If there is a missing cluster, I can imagine it being some more "relational" skillset around doing high-quality emotional labor, or maybe something genuinely associated with age and wisdom where certain skill domains are just really hard to perform well in without being at least 35+ and having the associated life experience. But I don't currently think such a cluster exists, and that four is really the right number.
https://www.sciencedirect.com/science/article/abs/pii/S0191886924004860
Claude lists: "Bo Jackson (NFL All-Pro + MLB All-Star). Deion Sanders (NFL HOF + MLB). Rebecca Romero (Olympic silver in rowing, then Olympic gold in cycling four years later — different disciplines entirely). Clara Hughes (Olympic medals in both speed skating and cycling). Rugby → NFL is a well-trodden path (Jarryd Hayne, Christian Wade)"
This research is a bit more controversial than I expected, but I don't really understand the controversy. There are definitely some people in the field who insist on there not being a strong general motor ability factor. IMO this study also points in the direction of there being a general motor ability.