Brain Food (part 8: a little more baseline)
As I mentioned earlier, while measuring my balance I’ve been listening to a book called Cod: The Fish that Changed the World. Around Hour 4 of the book I realized it was related to what I was doing: fish, brain food. Duh!
Each test of balance consists of 5 warmup trials followed by 15 regular trials. Each trial generates one number, a duration: how long I stand on one foot before the other foot touches the floor. It’s is a bit like surfing–balance, balance, balance, balance, balance, wipe out. (Surfers, skateboarders, skiers, snowboarders, gymnasts . . . this may interest you.) I enter the stopwatch times directly into my laptop. Each test lasts about 12 minutes. Because of the book, they’re pleasant.
I made several more baseline measurements of my balance with two changes:
1. To reduce fluctuations in the concentration of omega-3 in my brain, I did my best to take the flaxseed oil capsules as evenly spaced as possible. The general rule was to take 1 every 2.4 hours (= 10 per day). I didn’t take the capsules with me when I left home but I did follow that rule when I was home (not waking up to take them, however).
2. To make the distribution of (log) balance times more Gaussian (normal), I raised the maximum possible time from 30 seconds to 60 seconds. Previously I had stopped the test at 30 seconds; now the cutoff was 60 seconds. The problem was 30 seconds was too common — my balance was too good. Before the change, 3% of baseline measurements (6 out of 210) were 30 seconds. After the change, 12% of measurements (25 out of 210) were between 30 and 60 seconds and <1% (1 out of 210) were 60 seconds.
The graph below shows results (mean & standard error) for 28 sessions.
The early problem (first 10 tests), discussed in my previous post, was that the means were fluctuating too much. A one-way ANOVA, with each test a different level, gave F(9, 140) = 2.6, p = 0.008. This is why I started trying to evenly distribute the flax capsules over the day. This seemed to work. For the last 18 tests, F(17, 252) = 1.0, p = 0.4. Unfortunately there is obviously an upward trend but that is okay because the change I am going to make — much less omega-3 — should if anything impair balance.
August 9th, 2006 at 10:35 am
Aren’t you worried that your expectation of worser balance will skew the results?
August 13th, 2006 at 10:46 pm
[…] But, as you can see, there was a problem: My balance rapidly improved during the low omega-3 condition. Although the results support my original idea, they don’t support it as strongly as they might. A comment on a previous post was “Aren’t you worried that your expectation of worse balance will skew the results?” No, I’m not I thought when I read it. I had several reasons for not worrying about the effect of expectations, and now another has come along: Surprising results, which imply that expectations have little effect. I did not expect significant improvement from practice. I had believed that because I balance everyday for hours while standing and walking, there would not be a large practice effect. I was wrong. […]
September 5th, 2006 at 4:58 pm
Seth, what made you decide to use flax and walnut oils instead of fish oil for this experiment?
September 6th, 2006 at 8:29 am
I tried fish oil one day and got a headache the next morning. Maybe I took too much. Or maybe my fish oil was bad. I’ll try again.
January 15th, 2007 at 4:34 am
[…] I have done more self-experimentation about omega-3s and will describe the results in a week or two. Previous posts about omega-3 here, here, here, here, here, here, here, here, here, and here […]