Less Wrong is a community blog devoted to refining the art of human rationality. Please visit our About page for more information.

Recent updates to gwern.net (2011)

33 Post author: gwern 26 November 2011 01:58AM

A list of things I have written or researched in 2011 which I put on my personal site.

This has been split out to https://www.gwern.net/Changelog

Comments (18)

Comment author: lukeprog 26 November 2011 02:30:24AM *  20 points [-]

Your site remains one of the most useful personal sites I know of.

Comment author: gwern 26 November 2011 06:47:06AM *  12 points [-]

The irony being that the 'useful' stuff was just supposed to be a minor sideline to writing about philosophy and anime; eg. the DNB FAQ was born out of simple frustration with repeated threads on the dual n-back mailing list, the Silk Road article was for Kiba, etc...

Comment author: Metus 27 November 2011 07:01:36PM 1 point [-]

Nevertheless, I agree with lukeprog: Great work, keep it up. I always enjoy your updates.

Comment author: shokwave 27 November 2011 04:58:14AM 7 points [-]

Gwern's site has had at least as much impact as LessWrong on me, and possibly more. I highly recommend devouring it as ravenously as you might the Sequences.

Comment author: someonewrongonthenet 18 March 2013 03:36:15AM *  1 point [-]

Gwern, regarding Modafinil - have you looked into the interaction with COMT polymorphisms?

I read somewhere that carriers of the Val158Met polymorphism (mutation, under positive selection, reduces breakdown of dopamine in frontal lobe, increases working memory) do not see positive effects from Modafinil, while the ancestral Val carriers do see benefits.

I'll try to track down the study and post it when I have more time.

Comment author: gwern 18 March 2013 03:56:03AM 0 points [-]

The relevant study is cited in the page, yes. I am skeptical because there are so few studies and SNPs have a very bad track record of replication.

Comment author: someonewrongonthenet 22 March 2013 05:58:14AM *  3 points [-]

Hi, sorry to bother you again.

I was reading your Nootropics piece on Nicotine., and I noticed that for your placebo, you "dried out" your gum in the hopes that the nicotine would evaporate.

Your criteria for determining that the "dry" gum had no effect was to swallow a 4 mg dose and note that you felt no effects. You reasoned you would notice the effects because it made you dizzy last time you took that dose - but then you also noted that you didn't eat dinner, which could have also caused the effect, confounding your judgement.

However, you also noted that your guesses as to whether or not you had the placebo were worse than chance. This means that you aught to assign low confidence to your ability to predict whether or not you are under the influence of nicotine. In light of this, shouldn't you re-evaluate your initial, subjective assessment that the "dry' nicotine gum was really devoid of nicotine?

It is possible that the reason you were having trouble guessing because you were getting nicotine both in the "dry" and regular gum, albeit probably at different doses. Do you have a good reason to be confident that the nicotine would evaporate quickly from gum, other than knowing that it evaporates quickly and not subjectively feeling any effects from a dry 4mg dose?

Apologies in advance if I'm missing something important.

Comment author: gwern 22 March 2013 05:37:56PM *  0 points [-]

Your criteria for determining that the "dry" gum had no effect was to swallow a 4 mg dose and note that you felt no effects. You reasoned you would notice the effects because it made you dizzy last time you took that dose - but then you also noted that you didn't eat dinner, which could have also caused the effect, confounding your judgement.

I don't recall eating dinner before the test either, so that wouldn't be a confound.

However, you also noted that your guesses as to whether or not you had the placebo were worse than chance. This means that you aught to assign low confidence to your ability to predict whether or not you are under the influence of nicotine.

You're not comparing like with like here: 4mg is different from a 1mg dose. It's 400% larger, to be specific. If I took 800mg of modafinil rather than 200mg, I think I'd notice that...

It is possible that the reason you were having trouble guessing because you were getting nicotine both in the "dry" and regular gum, albeit probably at different doses. Do you have a good reason to be confident that the nicotine would evaporate quickly from gum, other than knowing that it evaporates quickly and not subjectively feeling any effects from a dry 4mg dose?

There's no reason that the nicotine would not evaporate. There was a lot of surface area (2 cut sides in addition to the substantial permeability of the gum itself), and I kept it out for 3 or 4 weeks, while all the sources I found spoke of substantial evaporation within minutes or hours and patches being useless after around a day - so I was giving myself a safety factor of >20x precisely to avoid this sort of issue.

Given the precautions I took, I think it's much more likely that the placebofying succeeded and my poor predictions were due to other factors: eg. tolerating to the point where 1mg did not produce significant effects (I hope not, since this would imply that my spacing out of gum use has failed and also that my experiment was an effort in measuring a null effect), the use of nicotine each day without any spacing out (see the writeup, I did this to avoid wasting gum since it was use-it-or-lose-it), or just another demonstration of how significant placebo effects can be (wouldn't be the first time!).

Comment author: wedrifid 22 March 2013 06:55:03PM 0 points [-]

while all the sources I found spoke of substantial evaporation within minutes or hours and patches being useless after around a day

That's interesting. I commonly cut nicotine patches and use them over a period of several days. Since the cut patches are no longer in the sealed package (but still have the plastic backing) should I expect the partial patches I use on the later days to be useless?

Comment author: gwern 22 March 2013 07:18:52PM *  1 point [-]

I'm not really sure. The more official sources seem to have in mind a full use of a patch, which I'd guess involves removing the full backing; people on Longecity discussing cutting up patches seem to think that you can cut up some brands of patches without too much of a problem and there will only be evaporation from the cut edge (but this is still fast enough that you might want to seal the edge somehow or use the cut patches within the week).

You could try removing the backing from some and then, 'several days' later, seeing if they feel the same as the usual ones.

Comment author: someonewrongonthenet 18 March 2013 04:50:30PM *  0 points [-]

Oh, whoops, I must have missed it on your page on first reat. I've been meaning to track that down and re-read it, thanks

It's true that allele-behavior interaction studies have really small effect sizes. Although, I do think that if someone has done the relevant genetic testing, it might be worth looking at the better studied dopamine alleles (DRD4 VNTR /DRD2 taq / DAT1 VNTR /COMT 158, etc) when deciding whether or not to take stimulants, since both extremes of the spectrum have somewhat similar cognitive disadvantages and they can be difficult to distinguish behaviorally.

Comment author: [deleted] 26 November 2011 03:33:05AM *  0 points [-]

Is there a place we could subscribe to your usual link feed?

EDIT: Nevermind, I remember where it is now. My bad.

For other people looking for gwern in their life: Here's the reader feed.

Comment author: gwern 26 November 2011 03:39:00AM *  2 points [-]

Unfortunately, Google broke the reader sharing functionality (we're all supposed to use Google+ now), and I haven't figured out where one gets RSS for that stream or how to transclude any of it onto gwern.net. Dang it Google!

Comment author: drethelin 26 November 2011 05:51:17AM -2 points [-]

just friend everyone on google+

Comment author: gwern 03 January 2012 12:52:16AM *  0 points [-]

Nah. I wound up using a third-party widget (you can see it in the footers) which loads my public Google+ shared items. It's a bit ugly, but it works.

EDIT: I ultimately removed it in favor of a simple link to my Google+ profile.

Comment author: JoshuaZ 26 November 2011 03:13:33AM 0 points [-]

The existential risk link doesn't seem to be going to anything.

Comment author: gwern 26 November 2011 03:22:18AM 0 points [-]

Yeah, I accidentally linked to the TOC - but I fixed that at least 40 minutes ago, so I don't know why you would still be having issues.

Comment author: JoshuaZ 26 November 2011 03:33:57AM 0 points [-]

I loaded the page a while ago and hadn't gotten around to looking at it.