I'm in my late twenties and increasingly worry about things like this. I sometimes wonder if my best "thinking days" are already behind me. Business sense and practicality (i.e. "wisdom") still seem to be increasing with time, yet I can't shake the feeling that understanding highly complex or novel topics is going to become vastly more difficult over the next few decades. For instance, if I wanted to learn homotopy type theory, would this have been easier five years ago, or will it be easier five years from now? It's well known that the number of neural synapses in the human brain decreases by almost an order of magnitude over a lifetime. I can accept that my body will degrade physically, but psychologically, I have a hard time stomaching the idea that my mental faculties are likely to erode as well. Hopefully exercise and eating well are enough to at least delay this as long as possible.
I'm in my early forties, and I've been having the same worries you list the whole time.
And the answer (for me, so far) is....it's complicated.
I definitely think I have a harder time processing new ideas. OTOH, I have a lot more context to connect them to, so I feel like I end up with a better understanding when I DO get them. I also have a wider perspective to decide WHAT I want to spend my precious time learning. When I do learn something, I'm less likely to think it's the answer to everything, while I'm still able to get excited and enjoy how much easier this makes many of my tasks.
And it's really hard for me to say how much is REALLY having a harder time grasping new ideas, and how much is a mix of (1) that additional context, which makes it harder/longer before I feel the sense that I truly "get" it (2) the overwhelming sense of how many things I DON'T know that makes it feel like "I'm not learning like I used to".
Docker has been on my list to learn for ~4 years, even though I've used it indirectly for most of that time, for example, but it's not that I haven't been learning new concepts in that time - I've just not been able to find free time where Docker has been on the top of my list. Kubernetes shows up on HN, and I've not done more than googled the general idea. Are these omissions because I don't have the capability to learn as well, or because I've got a very full schedule and mental web of connections to fit them into? No way to be sure - I don't know of any way to quantify them.
I try to make sure that I end each week being able to say I learned something new, and while those bits are often small, they are also often significant in my day-to-day.
Also, don't discount the impacts of physical decay on the psychological. Being unable to sit comfortably for long stretches, the wear and tear of a million tiny aches - they may as much to blame for psychological limitations from age as any direct neurological degradation.
I also wonder if there's a subtle psychological effect here: You, in particular, sound like you know a whole lot about at least a few things. But, that means when you tackle something new, the "know a lot about it" bar is set really high.
You're already an expert at X, so you know how hard it is to
become an expect at something, and when you start learning Y, it's clear how hard you have to work in order to get close to the same magnitude as your knowledge of X. As a result, it feels like it "takes longer" to learn stuff. But maybe it's just more stuff?
I think I heard this argument first made by Adam Savage (of Mythbusters fame).
Docker doesn't do anything shell scripts and zip files couldn't accomplish.
The only thing Docker does is distinguish a class of human oriented activities, such that everyone is talking about the same goals, and explaining ideas about the same conceptual objects, at the same time, across all platforms (Windows, Linux, Apple, BSD, AWS, VMware, Vbox), disciplines and job roles.
The DBA, the front-end JS developer, the sysadmin, the API developer, the SRE, the product team, the project managers, the tier one support and CRM call center, all of them are talking about the thing that standardizes virtual servers.
It's not that docker is particularly useful or special, but more to the point, different people are talking about doing the same thing the same way, and hopefully in 50 lines or less, because pressing the power button on a working computer, and plugging in the network cable needs to be made that simple, so that people can stop tripping over themselves about that least important of pizza topping conversations.
I’m 40 and it’s less that I can’t learn new ideas and it’s more that I have fairly settled ideas about how the world works and it’s hard for me to fully integrate new concepts without relearning a lot of other things at the same time.
I can learn new things as well as I could before, it just takes a bit of effort to clear space for it, as it were.
That you used the word "relearn" responding to a comment that mentions docker kinda hits it exactly for me: it's hard to get excited about a new way to do the same old thing, whereas when younger you don't yet have enough understanding/experience for it to have reached "same old thing" status.
> if I wanted to learn homotopy type theory, would this have been easier five years ago, or will it be easier five years from now?
My experience (I'm late 60s) suggests you may find it harder later, but you'll have a higher return because your newly-won expertise will connect with a richer experience base. You'll see connections you might have missed earlier.
And I doubt you'll notice much difference in five years. More like 15 - 20, I think.
After sleep and exercise, there are other medicines like eating the right food (at the right time of day) and meditation (again to be experimented with) which I've found help a lot.
I think it can help to at least plan your life. You may not need your best thinking days to start a family or work an average job, but if you want to invent something or research something new, it's probably best to do it in your youth.
Different people will have different comments on this post I think.
I think I am just as sharp as I ever was. I am in my early 50s. I do not however think I am as fast as I used to be. I can feel that. My understanding and abilities are solid as ever but I can see younger guys grokking things faster than me.
I also require way more sleep than I used to need.
The good thing though is that I have seen a LOT of things in my career in computers/programming/devops/engineering/math. So new things are just variations on things I have already seen over the years.
Nearing forty and feel (and am told) I'm doing the best work of my career. I think the same of my boss who's in his fiftys. One of the keys has been developing deep expertise in complex subject(s) I like and keeping up with the cutting edge. Also finding a career that lets you do this.
I am in my mid thirties and would say I definitely do not think I am as sharp now as I was as a teenager.
That said, I am overall much happier now.
For me, mental agility has proven less important to me than a number of things. Example: I have been hit by motorists a few times (I am a cyclist.) and my left knee has really taken a beating as a result. Keeping it in good shape so that I can continue to run and bike is much more important to me than, for example, being able to quickly memorize or learn something. As I see it, mere speed at assimilating information is a luxury whereas physical mobility is a necessity for having a life worth living.
Conversely, certain things have gotten better with age: my financial wellbeing and emotional maturity both come to mind.
Although I try not to worry about the inevitable and live in the now, I am personally more concerned about the point in my life where my body will entirely preclude certain activities.
With ago also comes different perspectives. Yes, learning is important, but your scope of vision, so to speak, may be broader and more nuanced. You may not quite value the ability to learn some hyper-specific niche thing quite as much.
Does it really matter? If you really want to learn something just go for it, for me the problem does not lie in the difficulty but to remain persistent as with age you start to question the point of your chosen interests too.
