There is a Yahoo Group about self-experimentation. Nobody told me! Many interesting posts and links. One posting within the last week, says the site, but I can’t find it. The most recent burst of activity was in May.
Category: self-experimentation
Science in Action: Exercise (15-minute walk)
Exercise reduces reaction time, I’ve found. What’s the threshold? I wondered — how little exercise do you need to get the effect? I wanted to know so that in my omega-3 experiments, I could be active — e.g., walk to a cafe — without distorting the results. Also, for practical reasons, I wanted to produce the effect as easily as possible.
To learn more about the threshold, I walked on my treadmill for 15 minutes at a comfortable speed (2.8 miles/hour). Here’s what happened:
If anything, the short walk increased reaction time. Thirty minutes of walking produced a clear (and repeatable) decrease, so the the effect appears to require between 15 and 30 minutes of walking.
I did this experiment three days ago. Self-experimentation is many times easier than conventional science; blogging is many times easier than conventional publishing. A powerful combination, I hope.
Science in Action: Exercise (more confirmation)
How little exercise will produce the reaction-time-lowering effect I’ve found (here and here)? I decided to measure the effect of a 10-minute walk from a BART stop to a cafe. (Nicely integrating work and work.) But I got off BART at the wrong stop and my 10-minute walk took 40 minutes.
Here is what happened:
Just as with a 30-minute treadmill walk, the effect was delayed.
This is more support for the idea that exercise temporarily improves brain function. The novelty in this particular experiment is that the exercise was “real” rather than on an indoor treadmill.
For comparison, here are earlier results from much more strenuous exercise (30 minutes walking uphill on a treadmill):
The effect of more strenuous exercise was larger and lasted longer. With the easier exercise (the stroll) there was a downward spike in reaction time; with the more difficult exercise (the climb) there was a more crater-like effect. The spike shape suggests the effect was sub-maximal; the crater shape suggests that the maximum effect was reached. Which makes sense because the climb was close to maximum effort, whereas the stroll was far below it.
A kind reader pointed to a NY Times article on the brain effects of exercise. “Exercise can, in fact, create a stronger, faster brain,” says the article. “Create” refers to neurogenesis. The effects I’ve observed are more temporary — more like adding better fuel to a car.
“The human brain is extremely difficult to study, especially when a person is still alive,” says the article. Not entirely true.
Science in Action: Exercise (confirmation)
During my omega-3 tests, I noticed that exercise seemed to be reducing reaction time (= better brain function). When I tested this, the results surprised me: Reaction time wasn’t lower immediately after exercise but became lower later. Did exercise have a delayed effect or was the shower I took soon after exercise responsible?
To find out, I did a little experiment. The earlier exercise was 30 minutes on a flat treadmill at about 2.8 miles/hour; this time I walked 30 minutes on a steep treadmill at higher speed (about 3.7 miles per hour). Here are the results:
Vertical lines show when the exercise started and stopped. This time there was improvement immediately after the exercise (unsurprising, given that it was much more intense) but even more improvement a half-hour later. I took a shower several hours later; it had no clear effect. The improvement lasted several hours before starting to diminish.
The data are very clear. They imply the earlier results can be believed: Exercise does improve brain function in an unanticipated way. Losing weight with exercise is hard; improving brain function with exercise appears easy. I want to study this effect in detail. Not only should it teach me how to improve brain function, it should also suggest the best dose of exercise for the rest of my body.
Science in Action: Methodology surprise and improvement
I’ve been using a letter-counting test to keep hour-by-hour track of how well my brain is working. The test consists of 200 trials that ask how many of four displayed letters (e.g., YCAW) are from the set {ABCD}. for YCAW, the answer is 2. Faster answers = better brain function.
For the first several hundred tests, I kept the location of the four letters constant: the center of the window. As soon as I answered, the next display appeared in the same position as the last one. The display never repeated immediately; for example UXRA was never followed by UXRA. But UXRA could be followed by UXAR. This was too easy because it looked like the A and R had switched places. This was a big difference from the usual appearance and it signalled that the answer had not changed. Overlap between one display and the next was probably important but was hard to measure.
To make the test more uniform across trials, I had the display move up and down, which eliminated overlap between one display and the next. Successive displays appeared above center, below center, above center, below center, etc.
To my great surprise, this made the task a lot easier. Here are accuracy scores before and after the change:
Before the change, mean accuracy was 94.9% (standard error 0.2); after the change, 97.4 (standard error 0.3). The error rate was cut in half, in other words. I had no idea this would happen.
Reaction times were slightly more after the change. A treatment that changes reaction time and accuracy in conceptually opposite directions — makes the task harder in terms of reaction times (= longer reaction times) but easier in terms of accuracy (= great accuracy) — is very unusual. I don’t know of any other examples.
The displays have always been big black letters on a white background — very easy to read. But this change made them seem more visible somehow. At some high level of my visual system, it was if the contrast had been improved. It’s a funny feeling because I thought I was seeing them perfectly clearly with the old procedure.
Because accuracy is better it is now closer to constant, which is what you want in a reaction-time experiment. You want as much variation in reaction time as possible and as little variation in accuracy as possible.
Science in Action: A Puzzle
To learn how omega-3 affects brain function, I’ve been doing a letter-counting test several times per day. I’ve posted some results. Several times after exercise (treadmill and street walking) my reaction times were faster than expected — meaning my brain was working better than expected.
Does exercise improve brain function? In a chapter on self-experimentation that he and I wrote, Allen Neuringer described several experiments in which other measures of brain function improved after exercise. I wanted to learn more about this for two reasons: 1. Reduce “noise”. If I know how much exercise is needed to get the effect, I can be careful to stay below level that while doing omega-3 experiments. 2. Practical value. You might call it nature’s caffeine.
So I did a little experiment. I walked on a flat treadmill for 30 minutes and did the letter-counting test several times. Here are the results:
The line shows the middle of the exercise; the exercise ended a few minutes before the first post-exercise test. To my surprise, the first post-exercise test showed no effect. I was wrong, I thought. But to my further and greater surprise later tests showed an effect in the predicted direction.
Between the first post-exercise test and the second, I took a shower. I will need to see if showers have an effect. If not, then apparently exercise has a delayed effect. No one has ever proposed this, I’m pretty sure.
Most of my self-experimentation has studied elements of ancient life. Omega-3, for example — I believe our ancestors ate lots of seafood (the Aquatic Ape Theory). They surely walked a lot.
Prozac Dangerous to Mussels
No joke. Prozac in the water may be endangering the mussel population, now in serious decline. For more on such side effects of antidepressants, see Toxipedia.
My self-experimentation led me to believe that morning faces = Nature’s antidepressant. Morning faces = mussel-safe.
Annals of Self-Experimentation: J. S. Haldane
J. S. Haldane (1860-1936) was an English physiologist. (The better-known J. B. S. Haldane, a geneticist, is his son.)
He believed that there was no better experimental subject than the scientist himself. . . . Routinely, the accounts of his experiments involve vomiting, convulsions, trembling, confusion and sometimes memory loss. At one point, experimenting with extremes of low barometric pressure, and after writing ‘very wobbly’ as a self-assessment on a piece of paper, he stared into a hand-mirror to check himself for the blue lips — cyanosis — that would indicate anoxaemia. He did this for a long time. Turned out he was looking at the back rather than the front of the mirror. . . .
When the Germans started experimenting with gas warfare — chlorine at first, and later mustard gas — Haldane led the race to provide effective protection for the troops. (As ever, this involved gassing himself half to death.) . . . Having heard about the gas attacks, Churchill declared blithely: ‘Oh, what you want is what we have in the navy. Smoke helmets or smoke pads, and you make them out of cotton wool or something. You’d better get the Daily Mail to organize the making of a million of them.’
Haldane pointed out that while a pad of cotton wool clamped to the mouth might help a little with smoke inhalation, it wouldn’t offer the slightest protection against chlorine gas. Yet not long afterwards Haldane returned from France to discover the Times reporting that the War Office had appealed for donations of home-made gas-masks from cotton wool or ‘double stockinette’. Haldane, furious, was reassured that this was merely a propaganda exercise, and that the useless masks wouldn’t be dispatched to the Front. Yet, again, not long afterwards 90,000 of them found their way to France — and proved just as much help as Haldane predicted.
Meanwhile, Haldane and his team worked like mad at designing effective respirators, tearing up stockings and shawls and even the young Aldous Huxley’s scarf to make face-masks. The one they came up with went into mass production — but not before Haldane had to point out that the reason the women in the factory were getting their fingers burnt and their rubber gloves dissolved was that they were using caustic soda rather than, as prescribed, carbonate of soda.
From a review of a new biography of Haldane. Another review by Lynn Truss. Biographer’s blog. A third review.
Thanks to Dave Lull.
Nassim Taleb on Research Strategy
In Forbes, Nassim Taleb, author of The Black Swan, made some comments I like:
Things, it turns out, are all too often discovered by accident. . . . Academics are starting to realize that a considerable component of medical discovery comes from the fringes, where people find what they are not exactly looking for. It is not just that hypertension drugs led to Viagra or that angiogenesis drugs led to the treatment of macular degeneration, but that even discoveries we claim come from research are themselves highly accidental. They are the result of undirected tinkering narrated after the fact, when it is dressed up as controlled research. The high rate of failure in scientific research should be sufficient to convince us of the lack of effectiveness in its design. If the success rate of directed research is very low, though, it is true that the more we search, the more likely we are to find things “by accident,” outside the original plan.
If the success rate per test is low, a good research strategy is to start with low-cost tests. Ants do this: They search with low-cost tests (single ants), exploit with high-cost tests (many ants). I don’t think the need to use different tools at different stages in the scientific process is well understood. John Tukey used the terms exploratory data analysis and confirmatory data analysis to make this point about data analysis but distinguishing exploratory and confirmatory experimental design is much less common.
I think my self-experimentation has been productive partly because it is a low-cost way of testing. All my interesting discoveries were accidents. My latest omega-3 research started with an accidental observation.
Science in Action: Omega-3 (VSE)
VSE = Very Short Experiment. After VSL (Very Short List). I did this experiment yesterday. It took the whole day but the results were clear by noon.
At about 7 am I took 4 tablespoons of flaxseed oil (Spectrum Organic). I measured my mental function with a letter-counting test. Here is what happened.
My reaction times decreased 2-3 hours after drinking the flaxseed oil. Over the next 6-8 hours they returned to baseline.
For cognoscenti, here are the accuracy data:
Accuracy was fairly constant.
These results resemble earlier time-course measurements (here and here). What pleases me so much is not the confirmation — after the earlier two results I had found the dip a third time and had found that olive oil does not cause a dip — but how fast and clear the main result (the dip) was. I could have done a mere four tests (7, 8, 10, 11 am) and found interesting results — I knew that the 8 am test was too early to see a difference so it would have been two tests “before” and two “after”. Six hours of testing can say something interesting about what we should eat and how to make our brains work best.
If you’ve been reading this blog you won’t be surprised that flaxseed oil helps; what’s new is how easily I can test a big wide world of foods. Salmon, trout, herring, fish oil, olive oil, canola oil, walnut oil, soybean oil, and so on. All sources of fat. Not to mention eggs.
I take 4 tablespoons of flaxseed oil most days; I am not suffering from too little omega-3, as most people are. This improvement is on top of the improvement produced by getting enough omega-3 most days. If I stopped taking flaxseed oil, my mental function would slowly get worse, as an earlier experiment (here and here) showed.