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.)

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.

Ah, it's just like "What Would Jesus Do" bracelets.

I'd recommend a persona over a role. Make it a person to inhabit, instead of an idea to correspond to.

I have no idea whether an experiment like one you describe would show a difference. I think there is probably some kind of bottleneck in the data the retina sends to the brain, and I imagine that could stand in the way of testing my attention in the way you describe. But the basic point is interesting.

I could imagine lots of experiments which I believe would likely show a difference in perception and attention between people who meditate in the way I've described and people who don't. For example, I claimed that mode four perception has "wide attentional width". It seems likely that this implies that a person in that mode of perception would be much better at attentional tasks involving simultaneous recognition of objects in different parts of the visual field. (For example, imagine watching a large computer screen that flashes two images, at the far left and right sides simultaneously, and having to explicitly say something about what properties those images had.) And since I can get into mode four perception when I want to, I should be better at these tasks.

On the other hand, most low-level cognitive processes are inaccessible to introspection, so without any knowledge of cognitive psychology, I have no idea whether the feature of experience I call "wide attentional width" would translate into this particular finding, or not do so because of some detail about human cognition that cognitive psychologists know about but I don't.

So, ultimately, I expect that a variety of tests along these lines would find obvious differences, but I don't have enough knowledge to pick out any particular one.

Risto Saarelma mentions EEG readings, and I imagine that meditating in the way I describe would produce obvious effects there, though I don't know enough about EEG readings to predict what they would be.

In general I worry that this is not a helpful line of thinking to pursue. Finding these effects would show that the time I've invested in meditating has affected the functioning of my brain with respect to attention and perception. Would this really be a surprising result to you? I would expect that a person who pursues any exercise in attention and perception is likely to show differences in attention and perception compared to a person who doesn't, simply due to neuroplasticity, even if they aren't exercises in attention and perception that would ever lead to enlightenment. I don't see that being able to demonstrate these differences would have a very large bearing on the claims I've made that people here have found controversial (though it would have some bearing on them).

There's a couple potential advantages to having a horcrux in Harry's possession: Harry's then guarding it, and it might be used to possess Harry later on. Though that's less helpful if, as in canon, Harry is a horcrux. But even then, I'd hardly be shocked to see Voldemort creating an additional horcrux on a whim.

Blaming the Pioneer Plaque for the progressive degredation sounds like it makes sense at first, but the point of the Pioneer Plaque thing is that this Voldemort is supposed to be smarter than canon Voldemort, and a Pioneer Plaque horcrux superior. That theory makes the Pioneer Plaque horcrux inferior. Also I'm pretty sure Voldemort has other horcruxes, including Roger Bacon's diary and quite possibly ones hidden in the other locations Harry suggested when discussing how to get rid of a Dementor.

I am amazed that Eliezer managed to take Rowling's most corny idea and made it non-corny: "The power that the Dark Lord knows not" is, after all, none other than the power of true love. And it is a mighty power not because of a hokey magical force attached to it, but because someone who feels it in addition to being rational is motivated to reshape the universe. "Power comes from having something to protect."