5 ms·

Are the measured effects of tDCS really large enough to outweigh any effects from confirmation bias and statistical anomalies? Were the tests performed double-b

by achy 15y ago

Are the measured effects of tDCS really large enough to outweigh any effects from confirmation bias and statistical anomalies? Were the tests performed double-blind using placebo units?

steve-howard 15y ago
Gotta agree with the placebo question here. When I'm having a really excellent learning day, it scares me how fast I learn. When I'm not, a 9V battery to the head doesn't sound like the worst idea...
- achanlon 15y ago
  Agreed. I listened to an article recently about a study that purported to show that wearing a 'lab coat' increased performance. Similarly, I believe that the tDCS results could be explained by a form of mental 'priming'.
- eagsalazar 15y ago
  Read the articles. Studies were done double blind. There is no placebo effect.
njs12345 15y ago
This study (paywalled) http://www.sciencedirect.com/science/article/pii/S1053811910014667 http://www.sciencedirect.com/science/article/pii/S1053811910... shows learning increasing with an increase in applied current, at least — 'This relationship between current strength and learning as measured by change in performance with training was well predicted by a linear model of current strength (r = 0.437, p = 0.0015). This suggests that there was a strong relationship between the amount of current administered during training and the amount of learning, within the range of current strengths tested here.'
- gwern 15y ago
  http://dl.dropbox.com/u/5317066/2012-clark.pdf http://dl.dropbox.com/u/5317066/2012-clark.pdf "TDCS guided using fMRI significantly accelerates learning to identify concealed objects"
  - phaker 15y ago
    A MRI machine is probably not included in the $99 kit. :) I was skeptical that simple, unguided tDCS could have significant effects so I searched some more and found a very nice overview paper: http://www.aipass.org/files/TDCS_State%20of%20the%20art.pdf http://www.aipass.org/files/TDCS_State%20of%20the%20art.pdf "Transcranial direct current stimulation: State of the art 2008"
    - gwern 15y ago
      That overview seemed to be more about what exact methodology future studies should use. The Nature article had more of an overview than that.
      - phaker 15y ago
        The article I linked references lots of research that had shown measurable results, including research on stimulation of large brain areas, which is all that you'd be able to do with this $99 kit. I was looking for something, anything, that would tell me if there's significant research in the area and if simple procedures that could be carried out using this kit would work. (Also you might note that the Nature article was linked 9 hours after my post :) In some ways it does give a better overview of the technique, I'd link it if I had found it.)
scotch_drinker 15y ago
At the risk of appealing to authority, I have to assume that if DARPA is using it to train snipers, they know it works whether it's due to the tDCS or mental priming as mentioned below. Obviously, from a theoretical standpoint it's important to know why it's working but from a lifehacking/making better snipers/learning Perl/selling $99 tDCS kits standpoint, it doesn't matter how it works, only that it does.
- wickedchicken 15y ago
  > I have to assume that if DARPA is using it to train snipers, they know it works This keeps getting thrown around but I'm having a hard time identifying a good source (other than a bunch of blogs repeating the same 'fact'). The best I can do is this set of slides which claim 'a 2.1x improvement' [1], but no confirmation that it's actually in use. The brain is very poorly understood, and throwing random electrical fields across it "because I saw it on extremetech" is a terrible idea. [1] http://www.dtic.mil/ndia/2008intell/kruse.pdf http://www.dtic.mil/ndia/2008intell/kruse.pdf
  - alexyoung 15y ago
    I remember reading more detail on the snipers here: Zap your brain into the zone: Fast track to pure focus http://www.newscientist.com/article/mg21328501.600-zap-your-brain-into-the-zone-fast-track-to-pure-focus.html?full=true http://www.newscientist.com/article/mg21328501.600-zap-your-... Which references Experimental Brain Research, vol 213, p 9: http://www.mendeley.com/research/transcranial-direct-current-stimulations-effect-novice-versus-experienced-learning/ http://www.mendeley.com/research/transcranial-direct-current...
- marshray 15y ago
  Well DARPA is an applied research funding organization, not a sniper training organization. So their funding doesn't automatically mean it was successful. Nevertheless, they probably wouldn't have funded it without some indication that it could be useful.
- DanBC 15y ago
  DARPA (and other defence budgets) can fund all kinds of weird stuff. Reasons range from "it works" through "it's a safe useful placebo" through "it might work" to "it doesn't work, but it'll confuse (and scare) the communists and divert them from our real research."

by achy 15y ago

Are the measured effects of tDCS really large enough to outweigh any effects from confirmation bias and statistical anomalies? Were the tests performed double-blind using placebo units?

steve-howard 15y ago

Gotta agree with the placebo question here. When I'm having a really excellent learning day, it scares me how fast I learn. When I'm not, a 9V battery to the head doesn't sound like the worst idea...

achanlon 15y ago
Agreed. I listened to an article recently about a study that purported to show that wearing a 'lab coat' increased performance. Similarly, I believe that the tDCS results could be explained by a form of mental 'priming'.
eagsalazar 15y ago
Read the articles. Studies were done double blind. There is no placebo effect.

njs12345 15y ago

This study (paywalled) http://www.sciencedirect.com/science/article/pii/S1053811910014667 http://www.sciencedirect.com/science/article/pii/S1053811910... shows learning increasing with an increase in applied current, at least — 'This relationship between current strength and learning as measured by change in performance with training was well predicted by a linear model of current strength (r = 0.437, p = 0.0015). This suggests that there was a strong relationship between the amount of current administered during training and the amount of learning, within the range of current strengths tested here.'

gwern 15y ago
http://dl.dropbox.com/u/5317066/2012-clark.pdf http://dl.dropbox.com/u/5317066/2012-clark.pdf "TDCS guided using fMRI significantly accelerates learning to identify concealed objects"
- phaker 15y ago
  A MRI machine is probably not included in the $99 kit. :) I was skeptical that simple, unguided tDCS could have significant effects so I searched some more and found a very nice overview paper: http://www.aipass.org/files/TDCS_State%20of%20the%20art.pdf http://www.aipass.org/files/TDCS_State%20of%20the%20art.pdf "Transcranial direct current stimulation: State of the art 2008"
  - gwern 15y ago
    That overview seemed to be more about what exact methodology future studies should use. The Nature article had more of an overview than that.
    - phaker 15y ago
      The article I linked references lots of research that had shown measurable results, including research on stimulation of large brain areas, which is all that you'd be able to do with this $99 kit. I was looking for something, anything, that would tell me if there's significant research in the area and if simple procedures that could be carried out using this kit would work. (Also you might note that the Nature article was linked 9 hours after my post :) In some ways it does give a better overview of the technique, I'd link it if I had found it.)

scotch_drinker 15y ago

At the risk of appealing to authority, I have to assume that if DARPA is using it to train snipers, they know it works whether it's due to the tDCS or mental priming as mentioned below. Obviously, from a theoretical standpoint it's important to know why it's working but from a lifehacking/making better snipers/learning Perl/selling $99 tDCS kits standpoint, it doesn't matter how it works, only that it does.

wickedchicken 15y ago
> I have to assume that if DARPA is using it to train snipers, they know it works This keeps getting thrown around but I'm having a hard time identifying a good source (other than a bunch of blogs repeating the same 'fact'). The best I can do is this set of slides which claim 'a 2.1x improvement' [1], but no confirmation that it's actually in use. The brain is very poorly understood, and throwing random electrical fields across it "because I saw it on extremetech" is a terrible idea. [1] http://www.dtic.mil/ndia/2008intell/kruse.pdf http://www.dtic.mil/ndia/2008intell/kruse.pdf
- alexyoung 15y ago
  I remember reading more detail on the snipers here: Zap your brain into the zone: Fast track to pure focus http://www.newscientist.com/article/mg21328501.600-zap-your-brain-into-the-zone-fast-track-to-pure-focus.html?full=true http://www.newscientist.com/article/mg21328501.600-zap-your-... Which references Experimental Brain Research, vol 213, p 9: http://www.mendeley.com/research/transcranial-direct-current-stimulations-effect-novice-versus-experienced-learning/ http://www.mendeley.com/research/transcranial-direct-current...
marshray 15y ago
Well DARPA is an applied research funding organization, not a sniper training organization. So their funding doesn't automatically mean it was successful. Nevertheless, they probably wouldn't have funded it without some indication that it could be useful.
DanBC 15y ago
DARPA (and other defence budgets) can fund all kinds of weird stuff. Reasons range from "it works" through "it's a safe useful placebo" through "it might work" to "it doesn't work, but it'll confuse (and scare) the communists and divert them from our real research."