has anyone actually gotten smarter, in the past few years, by studying rationality?

I never would have gotten a business off the ground without understanding concepts like the outside view, the introspection illusion, anchoring, fox vs hedgehog thinking, belief constraining expected evidence, basic statistics, and many more.

But it's more than that. LW type material upgraded my understanding of what it means to understand material. Previously I was doing a lot of guessing the teacher's password, CYA, moral licensing etc in justifying my actions to myself. Building models of when and where to apply concepts, how to seek out new ones when the existing concepts are insufficient, and how to validate them against problem domains is as important as the concepts themselves.

This is partly the difference between LW and just handing someone a copy of Thinking Fast and Slow. In the latter case, I would have read the book, gone "yes, that sounds very nice" and then continued on my way (I think).

The most important benefit from less wrong ist that before lw I hat a very fixed mindset of things I know and I don't, like if it were properties of the things in itself, and when I wanted to improve at something I just do it in a very vague directionless way.

A more concrete example is that I always liked modding video games but in modding is very limited what you can do comparing to coding, so at least once a year I make a half hearted attempt to learn get better at modding, which result in nothing because the next step always was to learn to code (which was in the "I can´t" bin ). After reading posts here of people doing awesome stuff , internalize that the map is not the territory and so, I realized that I could likely learn to code , an then the "I can't" bin broke. Exactly two years later know I'm fairly good with python , java and some of haskell just for the fun. I'm currently close to releasing an android game.

A life changing benefit I gain was to "cure" my social anxiety, it was mostly thanks to a post make here linking to Mark Manson, but it totally changed the way I interact with people from being all fear and uneasiness to flow and actually enjoying being around people (especially women).

Other less direct benefits are clearing a lot of philosophical confusion, save me from a couple of death spirals, I have the memorization problem mostly solved with spaced repetition, I change my mind more often, strategic thinking, meta-thinking and more stuff that's getting more abstract and I don't think is in the spirit of the question.

To answer the question, I DO think that my past self was dumber than me now, so in a way I'm gotten smarter.

Related LW article from 2009: Extreme Rationality: it's not that great by Yvain, also known as Scott Alexander.

Pre Less Wrong: Something bad happens. I freak out at all possible levels of freaking out, identify with failure, flinch away from unpleasant thoughts and thus fail even harder, react emotionally, try primarily to preserve my self-image.

Post Less Wrong: Somethjng bad happens. I compensate for my emotional reaction, prioritizing important choices with emphasis on making dispassionate decisions, try to pause even amid emotion and use a varied problem-solving toolkit to consider multiple solutions, more concerned with outcomes than appearances.

LW has definitely pointed me to some practical tools that have improved my decision making. Reading books tends to have helped more... but I would never have read those books if not for LW

How do you know it's not from simply growing older?

I think an often overlooked part of rationality is the wasted time and effort that LWers avoid put into irrelevant things: debating words' meaning, theology, blue/green affiliations, and so on. Not because of faith, but because all these have been dealt with.
True, it's not said that the resulting time/energy (action?) is put into more productive things, but it could be.

It worked for me - like I described here.

But the more obvious difference between LWers and non-LWers, according to me, is that LWers do not appear "stuck", while a solid majority of non-LWers do.

I'm a much better planner and guesser now. I make better bread (thanks Vaniver). And I'm not so miserly with money and avoid a few other dumb mistakes.

But that's about it - mostly this site is a hobby.

I'm definitely better at checking on whether information makes sense and/or is grounded in somewhat verified facts. Some of that is LW, some of that is a result of spending a lot of time online. I'm more cynical about psych studies, but probably not yet cynical enough.

Surprised there still wasn't a response despite seeing this post yesterday.

On topic, the best you can do is:

1. Start solving some problems;
2. Write down your thoughts, and compare them with your future thoughts
3. Read more, because even if you are rational it does not make you omniscient.

I don't think you should be worried much about intelligence either, I think it's vastly overrated.

Based off the very rough comparison of my SAT score with my GRE score, my IQ rose around 10 points in the interim (a gap of about 10 years), and I did begin reading LW during that period. However, my own impression is that most of the increase (if it even exists) came before I started reading LessWrong, and the increase instead came from economics blogs and literature recommendations which I mainly got from economics blogs. One of those early blogs was OvercomingBias, so I suppose that could be seen as a win for LessWrong. Previously, most of my reading had consisted of either school work or fiction, typically Sci-Fi or Fantasy.

The one improvement that I'm fairly certain I can contribute to lesswrong/HPMOR/etc is getting better at morality. First, being introduced to and convinced up utilitarianism helped me get a grip on how to reason about ethics. Realizing that morality and "what I want the world to be like, when I'm at my best" are really similar, possibly the same thing, was also helpful. (And from there, HPMOR's slytherins and the parts of objectivism that EAs tend to like were the last couple ideas I needed to learn how to have actual self esteem.)

But as to the kinds of improvements you're interested in. I'm better at thinking strategically, often just from using some estimation in decision making. (If I built this product, how many people would I have to sell it to at what price to make it worth my time? Often results in not building the thing.) But the time since I discovered lesswrong included my last two years of college and listening to startup podcasts to cope with a boring internship, so it's hard to attribute credit.

My memory isn't better, but I haven't gone out of my way to improve it. I'm pretty sure that programming and reading about programming are much better ways of improving at programming, than reading about rationality is. The sanity waterline is already pretty high in programming, so practicing and following best practices is more efficient than trying to work them out yourself from first principles.

It didn't surprise me at all to see that someone had made a post asking this question. The sequences are a bit over-hyped, in that they suggest that rationality might make the reader a super-human and then it usually doesn't happen. I think I still got a lot of useful brain-tools from them, though. It's like a videogame that was advertiesd as the game to end all games, and then it turns out to just be a very good game with a decent chance of becoming a classic. (For the record, my expectations didn't go quite that high, that I can remember, but it's not surprising that some peoples' do. It's possible mine did and I just take disappointment really well.)

I didn't get 'smarter' per se, but I got much better with interpersonal communication and the start of this trend coincides with getting in touch with LW (It also overlaps the breakup with my ex-wife but I think I can rule out a causal connection there).

Actually a lot of specific changes in my behavior can be traced back to specific advice from LW. I cannot rule out that by natural development I might have acquired these from other sources but I think the sheer amount of changes speaks a clear language.

I considered a write-up of this development from my Rationality Diary entries and such (I think Brienne mentioned somewhere that we need more success stories) but my low success with more elaborate posts here has discouraged me from that.

I've noticed some positive changes in my work efficiency that seem to have happened after I took a more serious attitude to paying attention to my thought processes, writing things down, and systematically approaching tasks:

Though do take this anecdotal evidence with a grain of salt, as the below relates to a high school career (from 10th to 11th grade. I suspect you might not be able to get as effective gains if you're in a higher level environment like university or a technical career)

• I've been going to bed earlier this year, despite having a heavier workload in school (around 1 hour earlier, on average, from 10:30 to 9:30).
• I've managed to maintain approximately the same grades while doing so, and I'm managing to work in more time to read books (~30 min day) and now exercise every two days (~50 min), and end all computer usage after 7:00, phones and tablets included, all habits I didn't consciously form last year when I hadn't paid much attention to how I thought about things and used time.

Firstly, like WoodSwordSquire I now support (total) utilitarianism. Secondly, I am much more confident at solving philosophical problems. Many philosophical puzzles which I found difficult in the past now seem rather clear to me. Thirdly, I am more aware of the assumptions that I am making and hence better able to critique them.