Posts

Why has the replication crisis affected RCT-studies but not observational studies? 2021-09-03T21:43:36.593Z
Factors of mental and physical abilities - a statistical analysis 2021-08-17T20:42:28.310Z
Alcohol, health, and the ruthless logic of the Asian flush 2021-06-04T18:14:08.797Z
The irrelevance of test scores is greatly exaggerated 2021-04-15T14:15:29.046Z
Poll: Any interest in an editing buddy system? 2020-12-02T02:18:40.443Z
Simpson's paradox and the tyranny of strata 2020-11-19T17:46:32.504Z
It's hard to use utility maximization to justify creating new sentient beings 2020-10-19T19:45:39.858Z
Police violence: The veil of darkness 2020-10-12T21:32:33.808Z
Doing discourse better: Stuff I wish I knew 2020-09-29T14:34:55.913Z
Making the Monte Hall problem weirder but obvious 2020-09-17T12:10:23.472Z
What happens if you drink acetone? 2020-09-14T14:22:41.417Z

Comment by dynomight on Writing On The Pareto Frontier · 2021-09-17T22:06:47.658Z · LW · GW

I have two thoughts related to this:

First, there's a dual problem: Given a piece of writing that's along the Pareto frontier, how do you make it easy for readers who might have a utility function aligned with the piece to find it.

Related to this, for many people and many pieces of writing, a large part of the utility they get is from comments. I think this leads to dynamics where a piece where the writing that's less optimal can get popular and then get to a point on the frontier that's hard to beat.

Comment by dynomight on johnswentworth's Shortform · 2021-09-03T14:54:12.203Z · LW · GW

I loved this book. The most surprising thing to me was the answer that people who were there in the heyday give when asked what made Bell Labs so successful: They always say it was the problem, i.e. having an entire organization oriented towards the goal of "make communication reliable and practical between any two places on earth". When Shannon left the Labs for MIT, people who were there immediately predicted he wouldn't do anything of the same significance because he'd lose that "compass". Shannon was obviously a genius, and he did much more after than most people ever accomplish, but still nothing as significant as what he did when at at the Labs.

Comment by dynomight on How To Write Quickly While Maintaining Epistemic Rigor · 2021-08-30T00:54:17.918Z · LW · GW

I thought this was fantastic, very thought-provoking. One possibly easy thing that I think would be great would be links to a few posts that you think have used this strategy with success.

Comment by dynomight on Factors of mental and physical abilities - a statistical analysis · 2021-08-18T17:04:34.656Z · LW · GW

Thanks, I clarified the noise issue. Regarding factor analysis, could you check if I understand everything correctly? Here's what I think is the situation:

We can write a factor analysis model (with a single factor) as

where:

1. is observed data
2. is a random latent variable
3. is some vector (a parameter)
4. is a random noise variable
5. is the covariance of the noise (a parameter)

It always holds (assuming and are independent) that

In the simplest variant of factor analysis (in the current post) we use in which case you get that

You can check if this model fits by (1) checking that is Normal and (2) checking if the covariance of x can be decomposed as in the above equation. (Which is equivalent to having all singular values the same except one).

The next slightly-less-simple variant of factor analysis (which I think you're suggesting) would be to use where is a vector, in which case you get that

You can again check if this model fits by (1) checking that is Normal and (2) checking if the covariance of can be decomposed as in the above equation. (The difference is, now this doesn't reduce to some simple singular value condition.)

Do I have all that right?

Comment by dynomight on Factors of mental and physical abilities - a statistical analysis · 2021-08-18T16:38:18.943Z · LW · GW

Thanks for pointing out those papers, which I agree can get at issues that simple correlations can't. Still, to avoid scope-creep, I've taken the less courageous approach of (1) mentioning that the "breadth" of the effects of genes is an active research topic and (2) editing the original paragraph you linked to to be more modest, talking about "does the above data imply" rather than "is it true that". (I'd rather avoid directly addressing 3 and 4 since I think that doing those claims justice would require more work than I can put in here.) Anyway, thanks again for your comments, it's useful for me to think of this spectrum of different "notions of g".

Comment by dynomight on Factors of mental and physical abilities - a statistical analysis · 2021-08-18T13:56:32.592Z · LW · GW

Thanks, very clear! I guess the position I want to take is just that the data in the post gives reasonable evidence for g being at least the convenient summary statistic in 2 (and doesn't preclude 3 or 4).

What I was really trying to get at in the original quote is that some people seem to consider this to be the canonical position on g:

1. Factor analysis provides rigorous statistical proof that there is some single underlying event that produces all the correlations between mental tests.

There are lots of articles that (while not explicitly stating the above position) refute it at length, and get passed around as proof that g is a myth. It's certainly true that position 5 is false (in multiple ways), but I just wanted to say that this doesn't mean anything for the evidence we have for 2.

Comment by dynomight on Factors of mental and physical abilities - a statistical analysis · 2021-08-18T12:01:17.826Z · LW · GW

Can I check if I understand your point correctly? I suggested we know that g has many causes since so many genes are relevant and thus f you opened up a brain, you wouldn't be able to "find" g in any particular place. It's the product of a whole bunch of different genes, each of which is just coding for some protein, and they all interact in complex ways. If I understand you correctly, you're pointing out that there could be a sort of "causal bottleneck" of sorts. For example, maybe all the different genes have complex effects, but all that really matters is how they affect neuronal calcium channel efficiency or something. Thus, if you opened up a brain, you could just check how efficient the calcium channels are and you're done. Is that right?

If this is right, I do agree that I seem to be over-claiming a bit here. There's nothing that precludes the possibility of a "bottleneck" as far as I know, (though it seems sorta implausible in my not-at-all-informed opinion)

Comment by dynomight on Factors of mental and physical abilities - a statistical analysis · 2021-08-18T01:50:59.193Z · LW · GW

I used python/matplotlib. The basic idea is to create a 3d plot like so:

fig = plt.figure()


Then you can add dots with something like this:

ax.scatter(X,Y,Z,alpha=.5,s=20,color='navy',marker='o',linewidth=0)


Then you save it to a movie with something like this:

def update(i, fig, ax):
ax.view_init(elev=20., azim=i)
return fig, ax

frames = np.arange(0, 360, 1)
anim = FuncAnimation(fig, update, frames=frames, repeat=True, fargs=(fig, ax))
writer = 'ffmpeg'
anim.save(fname, dpi=80, writer=writer, fps=30)


I'm sure this won't actually run, but it gives you the basic idea. (The full code is a complete nightmare.)

Comment by dynomight on Factors of mental and physical abilities - a statistical analysis · 2021-08-18T00:40:13.562Z · LW · GW

Thanks for the reply. I certainly agree that "factor analysis" often doesn't make that assumption, though it was my impression that it's commonly made in this context. I suppose the degree of misleading-ness here depends on how often people assume isotropic noise when looking at this kind of data?

In any case, I'll try to think about how to clarify this without getting too technical. (I actually had some more details about this at one point but was persuaded to remove them for the sake of being more accessible.)

Comment by dynomight on What does knowing the heritability of a trait tell me in practice? · 2021-07-28T18:24:16.235Z · LW · GW

if a trait is 80% heritable and you want to guess whether or not Bob has that trait then you'll be 80% more accurate if you know whether or not Bob's parents have the trait than if you didn't have that information.

I think this is more or less correct for narrow-sense heritability (most commonly used when breeding animals) but not quite right for broad-sense heritability (most commonly used with humans). If you're talking about broad-sense heritability, the problem is that you'd need to know not just if the parents have the trait, but also which genes Bob got or not from each parent, as well as the effect of dominant genes, epistatic interactions, etc.

Assuming you're talking about broad-sense heritability, I think a better way of looking at it would be to say that you'll be 80% more accurate if Bob has an identical twin raised by a random family and you know if that twin had the trait. This isn't quite right either, but I think it's valid if you assume that phenotypic traits are the sum of genetic effects and environmental effects and also that genetic effects are independent of environmental effects.

Of course, few people have identical twins raised by random families, and most phenotypes probably aren't additive in genetic and environmental effects, and those effects probably aren't independent! Which... is a lot of caveats if you want to know practical applications of heritability numbers.

Comment by dynomight on What does knowing the heritability of a trait tell me in practice? · 2021-07-26T21:24:57.049Z · LW · GW

On the other hand, there is some non-applied scientific value in heritability. For example, though religiosity is heritable, the specific religion people join appears to be almost totally un-heritable. I think it's OK to read this in the straightforward way, i.e. as "genes don't predispose us to be Christian / Muslim / Shinto / whatever". I don't have any particular application for that fact, but it's certainly interesting.

Similarly, schizophrenia has sky-high heritability (like 80%) meaning that current environments don't have a huge impact on where schizophrenia appears. That's also interesting even if not immediately useful.

Comment by dynomight on What does knowing the heritability of a trait tell me in practice? · 2021-07-26T21:19:43.013Z · LW · GW

My view is that people should basically talk about heritability less and interventions more. In most practical circumstances, what we're interested in is how much potential we have to change a trait. For example, you might want to reduce youth obesity. If that's your goal, I don't think heritability helps you much. High heritability doesn't mean that there aren't any interventions that can change obesity-- it just means that the current environments that people are already exposed to don't create much variance. Similarly, low heritability means the environment produces a lot of variance, but it doesn't tell you anything specific you can actually do!

If you goal is to find interventions, all heritability gives you is some kind of vague clue as to how promising it might be to look at natural environmental variation to try to find interventions.

Comment by dynomight on Alcohol, health, and the ruthless logic of the Asian flush · 2021-06-07T18:12:37.647Z · LW · GW

In principle, I guess you could also think about low-tech solutions. For example, people who want to opt out of alcohol might have some slowly dissolving tattoo / dye placed somewhere on their hand or something. This would eliminate the need for any extra ID checks, but has the big disadvantage it would be visible most of the time.

Comment by dynomight on Alcohol, health, and the ruthless logic of the Asian flush · 2021-06-05T19:56:19.086Z · LW · GW

Thanks. Are you able to determine what the typical daily dose is for implanted disulfiram in Eastern Europe? People who take oral disulfiram typically need something like 0.25g / day to have a significant physiological effect. However, most of the evidence I've been able to find (e.g. this paper) suggest that the total amount of disulfiram in implants is around 1g. If that's dispensed over a year, you're getting like 1% of the dosage that's active orally. On top of that, the evidence seems pretty strong that bioavailability from implants is lower than from oral doses, so it's effectively even less.

Of course, there's nothing stopping someone implanting 100x as large a dose, and maybe bioavailability can be improved (or isn't that big a concern). But if not, my impression was that most implants are effectively pure placebo effect.

Comment by dynomight on Alcohol, health, and the ruthless logic of the Asian flush · 2021-06-05T17:41:40.398Z · LW · GW

Very interesting! Do you know how much disulfiram the implant gives out per day? There's a bunch of papers on implants, but there's usually concerns about (a) that the dosage might be much smaller than the typical oral dosage and/or (b) that there's poor absorption.

Comment by dynomight on Alcohol, health, and the ruthless logic of the Asian flush · 2021-06-05T01:48:53.196Z · LW · GW

I specified (right before the first graph) that I was using the US standard of 14g. (I know the paper uses 10g. There's no conflict because I use their raw data which is in g, not drinks.)

Comment by dynomight on Alcohol, health, and the ruthless logic of the Asian flush · 2021-06-04T21:38:12.665Z · LW · GW

Ironically, there is no standard for what a "standard drink" is, with different countries defining it to be anything from 8g to 20g of ethanol.

Comment by dynomight on Alcohol, health, and the ruthless logic of the Asian flush · 2021-06-04T21:03:49.914Z · LW · GW

I wasn't (intentionally?) being ironic. I guess that for underage drinking we have the advantage that you can sort of guess how old someone looks, but still... good point.

Comment by dynomight on The irrelevance of test scores is greatly exaggerated · 2021-04-22T13:58:21.628Z · LW · GW

I've politely contacted them several times via several different channels just asking for clarifications and what the "missing coefficients" are in the last model. Total stonewall- they won't even acknowledge my contacts. Some people more connected to the education community also apparently did that as a result of my post, with the same result.

Comment by dynomight on How is rationalism different from utilitarianism? · 2021-02-15T15:26:55.208Z · LW · GW

You could model the two as being totally orthogonal:

• Rationality is the art of figuring out how to get what you want.
• Utilitarianism is a calculus for figuring out what you should want.

In practice, I think the dividing lines are more blurry. Also, the two tend to come up together because people who are attracted to the thinking in one of these tend to be attracted to the other as well.

Comment by dynomight on Simpson's paradox and the tyranny of strata · 2020-11-20T19:04:13.112Z · LW · GW

You definitely need a number of data at least exponential in the number of parameters, since the number of "bins" is exponential. (It's not so simple as to say that exponential is enough because it depends on the distributional overlap. If there are cases where one group never hits a given bin, then even an infinite amount of data doesn't save you.)

Comment by dynomight on Simpson's paradox and the tyranny of strata · 2020-11-20T18:58:43.535Z · LW · GW

I see what you're saying, but I was thinking of a case where there is zero probability of having overlap among all features. While that technically restores the property that you can multiply the dataset by arbitrarily large numbers, if feels a little like "cheating" and I agree with your larger point.

I guess Simpson's paradox does always have a right answer in "stratify along all features", it's just that the amount of data you need increases exponentially in the number of relevant features. So I think that in the real world you can multiply the amount of data by a very, very large number and it won't solve the problem, even though in a large enough number will.

In the real world it's often also sort of an open question if the number of "features" is finite or not.

Comment by dynomight on It's hard to use utility maximization to justify creating new sentient beings · 2020-10-20T22:55:22.032Z · LW · GW

I like your concept that the only "safe" way to use utilitarianism is if you don't include new entities (otherwise you run into trouble). But I feel like they have to be included in some cases. E.g. If I knew that getting a puppy would make me slightly happier, but the puppy would be completely miserable, surely that's the wrong thing to do?

(PS thank you for being willing to play along with the unrealistic setup!)

Comment by dynomight on Message Length · 2020-10-20T15:10:43.458Z · LW · GW

This covers a really impressive range of material -- well done! I just wanted to point out that if someone followed all of this and wanted more, Shannon's 1948 paper is surprisingly readable even today and is probably a nice companion:

http://people.math.harvard.edu/~ctm/home/text/others/shannon/entropy/entropy.pdf

Comment by dynomight on It's hard to use utility maximization to justify creating new sentient beings · 2020-10-20T15:04:36.947Z · LW · GW

Well, it would be nice if we happened to live in a universe where we could all agree on an agent-neutral definition of what the best actions to take in each situation are. It seems to be that we don't live in such a universe, and that our ethical intuitions are indeed sort of arbitrarily created by evolution. So I agree we don't need to mathematically justify these things (and maybe it's impossible) but I wish we could!

Comment by dynomight on It's hard to use utility maximization to justify creating new sentient beings · 2020-10-20T00:33:27.400Z · LW · GW

If I understand your second point, you're suggesting that part of our intuition seems to suggest large populations are better is that larger populations tend to make the average utility higher. I like that! It would be interesting to try to estimate at that human population level average utility would be highest. (In hunter/gatherer or agricultural times probably very low levels. Today probably a lot higher?)

Comment by dynomight on It's hard to use utility maximization to justify creating new sentient beings · 2020-10-19T22:05:46.895Z · LW · GW

Can you clarify which answer you believe is the correct one in the puppy example? Or, even better, the current utility for the dog in the "yes puppy" example is 5-- for what values you believe it is correct to have or not have the puppy?

Comment by dynomight on Police violence: The veil of darkness · 2020-10-13T21:08:19.750Z · LW · GW

My guess is that the problem is I didn't make it clear that this is just the introduction from the link? Sorry, I edited to clarify.

Comment by dynomight on Doing discourse better: Stuff I wish I knew · 2020-09-29T19:20:53.726Z · LW · GW

Totally agree that the different failure modes are in reality interrelated and dependent. In fact, one ("necessary despot") is a consequence of trying to counter some of the others. I do feel that there's enough similarity between some of the failure modes at different sites that's it's worth trying to name them. The temporal dimension is also an interesting point. I actually went back and looked at some of the comments on Marginal Revolution posts years ago. They are pretty terrible today, but years ago they were quite good.

Comment by dynomight on Comparative advantage and when to blow up your island · 2020-09-21T23:03:15.826Z · LW · GW

In principle, for work done for market, I guess you don't need to explicitly think about free trade. Rather, by everyone pursing their own interests ("how much money can I make doing this"?) they'll eventually end up specializing in their comparative advantage anyway. Though, with finite lifetime, you might want to think about it to short-circuit "eventually".

For stuff not done for market (like dividing up chores), I'd think there's more value in thinking about it explicitly. That's because there's no invisible hand naturally pushing people toward their comparative advantage so you're more likely to end up doing things inefficiently.

Comment by dynomight on Making the Monte Hall problem weirder but obvious · 2020-09-18T02:38:12.006Z · LW · GW

Thanks for pointing this out. I had trouble with the image formatting trying to post it here.

Comment by dynomight on Making the Monte Hall problem weirder but obvious · 2020-09-17T17:13:52.941Z · LW · GW

That's definitely the central insight! However, experimentally, I found that explanation alone was only useful for people who already understood Monty Hall pretty well. The extra steps (the "10 doors" step and the "Monty promising") seem to lose fewer people.

That being said, my guess is that most lesswrong-ites probably fall into the "already understood Monty Hall" category, so...