[twmb]

I just have to comment that in his page, I disagree on using dual n back as a measure of mental ability. As the mind repeats a task over and over it learns what to expect.

I personally view n-back as any other repetitive task, only it is mostly in the mind; the more you whittle, the better you will be at whittling.

If you look at the wikipedia page [1] you will see that there have been papers both for and against n-back improving cognitive ability.

The way I propose to test effectiveness would be to have a bunch of subjects all try to learn a difficult task that is unfamiliar to them. Those with the placebo supposedly would not be able to learn it as quickly or understand it as well. The large sample size would account for statistical inaccuracies and differences among people's abilities.

I personally took nootropics this last winter for three months. My theory is that people who claim improvement are looking for improvement, and notice more just how good they are at tasks... I took piracetam, choline, aniracetam, and oxiracetam (and a tiny sample of pramiracetam, the supposed best, for free), and noticed nothing the entire time. Originally I thought I noticed improvement, but only realized I was looking for improvement in every task I did, which made me notice everything I did. After this realization I didn't notice anything at all, for the rest of my supplies. I learned more than just their ineffectiveness during this self experiment...

EDIT: I will revise my statement to add that I do not think that *racetams are completely ineffective. I do believe that they are relatively useless on healthy individuals without any disorders, though. Most of the studies in the wikipedia page are on people with disorders, and I do remember reading before that their benefits on people without problems is disputed.

[1]http://en.wikipedia.org/wiki/N-back

[gwern]

> I just have to comment that in his page, I disagree on using dual n back as a measure of mental ability. As the mind repeats a task over and over it learns what to expect.

So?

> I personally view n-back as any other repetitive task, only it is mostly in the mind; the more you whittle, the better you will be at whittling.

Progress in n-back is very slow. I'm up to 2400 rounds and still am only at 30-50% on D5B; a difference of 10% is perfectly noticeable.

> If you look at the wikipedia page [1] you will see that there have been papers both for and against n-back improving cognitive ability.

The Wikipedia page is completely useless compared to my FAQ, but yes. That's not relevant to whether it is a useful way to measure variations in mental ability.

[dlytle]

While you're here, I wanted to say thanks for all the research you've done and posted. It's been really useful reading.

Also, holy crap, D5B. I still get crushed on D3B.

[gwern]

You're welcome.

Yeah, I struggled on D3B, like I did on D2B, D4B, D5B... It's really impressive how each level is a sudden massive jump in difficulty.

[dlytle]

True, n-backs don't necessarily represent cognitive improvements, but they are a method to identify changes in some kinds of mental processes.

For instance, if you do Dual 3-Back for 3 weeks with an identical supplement regimen, you can graph the progressive improvement over time. That'll give you a semi-baseline, and if all you change (in your life) is a supplement from that point, you can attribute the alterations in your typical N-Back to something supplement related.

I know, placebo effect, etc. It's not causation, just correlation. Just because correlation gets pimped out on the street corner by people with agendas doesn't mean we should ignore him. We should just be careful when we utilize his services.