Another Mysterious Mental Improvement (2)

2010-12-28 puzzling improvement

A month ago I posted this graph, which shows how long I needed to type the answer to simple arithmetic problems (7-5, 4*1, 9+0). I tested myself with about 40 problems once or twice per day. Because I’d been doing this for a long time, I no longer improved due to practice. Then, at the end of July 2010, I started improving again.

In September I moved from Berkeley to Beijing. I was worried that in Beijing my scores would get worse. Perhaps I couldn’t get good flaxseed oil or butter. Maybe I would suffer from the air pollution. Maybe I would eat contaminated food. But my scores got better in Beijing.

When I eventually noticed the improvement, I wondered what I was doing differently. Obviously my diet and my life were a lot different in Beijing than Berkeley. Was I eating more walnuts in Beijing? I stopped eating walnuts and my scores didn’t get worse. So it wasn’t walnuts. The most plausible differences I could think of were: 1. Less aerobic exercise in Beijing. 2. Less vitamins in Beijing. 3. Warmer in Beijing. I collected data that implied that shower temperature matters — and I can take warmer showers in Beijing than in Berkeley.

All of these proposed explanations implied that the crucial difference was Berkeley versus Beijing. But the improvement started in Berkeley — around the end of July. That was a problem. Recently I realized there was another possible explanation. In Berkeley I had had an amalgam mercury-containing filling replaced with a non-metallic filling. Not because I had symptoms of mercury poisoning, but because it seemed prudent.

I checked my records to see when I had the filling replaced. It was July 28 — right when the improvement started. To my shock, reduction in mercury exposure is now the most plausible explanation of the improvement. Two tests of this explanation are coming up: 1. When I return to Berkeley, will my reaction times go up? 2. When I have more amalgam fillings replaced, will my reaction times go down?

If it turns out that reduction in mercury exposure is the correct explanation, this will be important. I have an average number of fillings. I’d guess that half of Americans have as many amalgam fillings as I did. And — if the mercury explanation is correct — this arithmetic test is a sensitive measure of mercury poisoning. Over the last few years, before the filling was removed, I’d had six hair tests done, all from the same reputable lab. They showed that my mercury level was moderately high, perhaps 75th percentile. Not very worrisome.

I changed dentists because my old dentist made a terrible mistake: he put a gold filling next to an amalgam one. Putting one metal next to a different one is an elementary mistake. Contact of different metals creates an electric current (as Galvani discovered) and releases mercury. (So although I have a normal number of fillings perhaps I have more mercury exposure.) I stopped going to him for any dental work. The last time I went there for a cleaning, I was given a booklet (“we must give you this”) about the many sorts of dental materials — mercury amalgams plus several new ones. The purpose seems to be to tell people mercury amalgams aren’t dangerous (this was stressed) yet get them to choose other materials in the future — mercury amalgams are just one of several possible choices. The controversy about the safety of mercury amalgams is covered here. Sweden, Denmark, and Norway have banned mercury amalgams. The ban began 2008.

15 Responses to “Another Mysterious Mental Improvement (2)”

  1. Joseph Dantes Says:

    Very impressive, and a strong argument that mercury’s effects are linear rather than threshold based.

  2. Anonymous Says:

    What lab did you use for hair analysis?

  3. Tyler Says:

    I’m interested to see where this goes. Both my parents have mercury fillings without apparent problems, but perhaps there’s room for improvement?

    Over the last couple years I’ve lost a lot of respect for the dental profession. Many of the practices seem rash- Mercury fillings, Fluoride applications, Bisphenol-A in all the resins/sealants… It strikes me as incredibly naive, to think that adding new substances such as these that have never been present for the last 2.5 million years of human evolutionary history in these quantities (or at all – BPA), won’t have any unintended side effects.

    What do you think?

    TS

  4. Alex Chernavsky Says:

    Seth, I’ve heard that the process of extracting a mercury filling itself results in a fairly large exposure to mercury. Any thoughts about this?

  5. Pip Says:

    What about fluoride in the water and toothpaste? I would bet that there is less exposure to fluoride in China.

  6. vic Says:

    I’ve read the non-metallic composite fillings have bisphenol-a and other chemicals that can leach… not particularly appealing either

  7. Gunnar Says:

    What material have you chosen as replacement?

    Be well.

  8. dearieme Says:

    I have long argued that the slightly reduced life expectancy of Americans relative to comparable nationalities is caused by their devotion to excessive dental work. You may have hit of the detailed mechanism.

  9. vic Says:

    also, has your sleep changed in association with your improved mental performance?

  10. Seth Roberts Says:

    Anonymous, the hair test lab is Doctor’s Data.

    Alex, the doctor took precautions but of course I had no idea at the time how adequate they were. These results suggest they were adequate, in the sense that the removal seems to have done more good than harm.

    Gunnar, good question but I don’t know what the replacement material is. The dentist did a weird chiropractic procedure in which he put various materials in my hand and pushed down. That is silly and next time I should figure out what I want.

    pip, since the change started in Berkeley the Berkeley/Beijing differences are not especially plausible.

    Tyler, unlike doctors, who do not themselves take the drugs they prescribe, dentists are exposed to the materials they use. Mercury poisoning is a serious risk among dentists. I don’t think anybody has claimed that the new substances wouldn’t have any unintended side effects; they just thought the new substances were likely to be an improvement over doing nothing. For example, ether anesthesia. Our houses are full of new substances, such as plastics and metals. They aren’t perfectly safe but they are on the whole improvements.

    vic, that’s a good question. I will look into it.

  11. Kim Øyhus Says:

    I was told by a dentist that Mercury amalgam is quite safe because it is an alloy with another metal, so the atoms are bound together, so there is no direct contact with Mercury itself.

    As a solid state physicist I know that is totally false. An amalgam is NOT an alloy. It is instead very thin layers of alternating pure metal, somewhat similar to the ridges in a finger print. This is what gives amalgams their flexibility and crack resistance.

    So there is indeed direct contact by tongue, spit, and food to pure poisonous Mercury, making even worse chemical products.

  12. Seth Roberts Says:

    Kim, good point. What I’ve read about dental amalgams did not make that clear.

  13. KillaCam Says:

    Seth,
    What “simple arithmetic problems ” test are you using? I’d like to start collecting data on myself!
    Thanks in advance,

  14. Seth Roberts Says:

    KillaCam, I use a set of problems generated in R (the programming language). I run the test using R.

  15. Stone Glasgow Says:

    What type of problems does the program ask you to solve?

    Seth: 3 + 8, 8 * 9, problems like that.