Tag Archives: Seth Roberts

The butter brain hypothesis

10 Oct

I always enjoyed reading the late Seth Robert’s blog. He never hesitated to question orthodoxies and always had some interesting new idea. However, some of the things he advocated were troubling. One example, of this was the butter brain hypothesis, the idea that consumption of butter might improve cognitive performance.

The idea is not implausible. The brain, after all, contains many lipids and the idea that consuming certain lipids might improve its performance does not sound unreasonable. The problem is butter is high in saturated fats and has been linked to heart disease.

I know, I know, many recent news reports tell us that “butter is safe” or that “butter is back.” These kind of person-bites-dog stories are popular in the media, but the science around saturated fats and cardiovascular disease is well established.

Here is an article from the New York Times reflecting on evolution and the dietary needs of the brain.

And here is a recent paper on the dangers of saturated fats. The abstract reads:

In recent years, many nutrition news headlines exclaimed that saturated fat was not linked to heart disease, leaving the public confused about whether to limit intake, as has been the dietary recommendation for several decades. However, a more nuanced look at the evidence indicates that high saturated fat diets are in fact not benign with respect to heart disease risk. Dietary recommendations should emphasize replacing saturated fats typical in red and processed meats, and certain tropical oils and dairy forms, with healthier polyunsaturated and monounsaturated fat-rich foods, such as nuts, olive oil, and fatty fish, as well as healthy sources of carbohydrates, such as fiber-rich whole-grain foods, rather than refined-grain and sugar-laden foods.

 

The crisis in science

4 Aug

The last posts of physiologist  Seth Roberts have been put up at his blog. One links to a post titled “Dear Academia, I loved you but I am leaving you.” The author includes this description of how science is sometimes performed:

“It’s just how it goes in those fields…remove all of the negative results, don’t actually report the ridiculous number of fishing expeditions you went on (especially in fMRI research), make it sound like you mostly knew what you were going to find in the first place, make it a nice clean story. When my colleagues (from a well-known, well-respected emotion research lab) were trying to talk me into removing all of the negative results and altering what my original hypothesis was, literally saying “everyone does it…” that was it for me. I had a sinking feeling that everyone did do it that way and that I couldn’t trust the majority of work I had to depend on/reference myself.”

To understand the importance of this crisis in research, see this article in Slate:

 

“The “replication crisis” is not at all unique to social psychology, to psychological science, or even to the social sciences. As Stanford epidemiologist John Ioannidis famously argued almost a decade ago, “Most research findings are false for most research designs and for most fields.” Failures to replicate and other major flaws in published research have since been noted throughout science, including in cancer research, research into the genetics of complex diseases like obesity and heart disease, stem cell research, and studies of the origins of the universe. Earlier this year, the National Institutes of Health stated “The complex system for ensuring the reproducibility of biomedical research is failing and is in need of restructuring.”

 

On self experimentation, soy, and memory

24 Mar

When I ask my students to read a research paper, they often argue that “the sample size was too small.” Typically, students who are new to statistical analysis do not understand the mathematics of sample size, and this becomes a reflexive criticism. If they don’t like the result of a study they argue that a larger sample was needed.

This is why students are often shocked when I talk about the value of single subject research and argue that it is possible to gain information when the sample size is N = 1. One of the advantages of single subject research is that you can control for background characteristics, such as genetics, because these traits remain constant over the individual.

One variant of single subject design is self experimentation, as advocated by the always interesting Seth Roberts. Roberts recently ran an experiment on himself where he found, in his words, that tofu made him “stupid.” To his credit Roberts recently linked to a post by  Alex Chernjavsky which reached the opposite conclusion:

 “The results were not consistent with the hypothesis that eating soy is harmful to brain function.  Surprisingly, my scores became significantly faster during the study.”

One possibility for the different results is that self-experimental trials are often not blinded, that is the subjects frequently know which treatment they are receiving and unconscious bias might play a role in the results. For example,  Roberts is an advocate of a meat based diet while Chernjavsky is a vegan. Chernjavsky, himself suggests:

“I don’t know why my results are inconsistent with prior work.  Perhaps people differ in their sensitivity to soy.  Or perhaps I’ve been eating so much soy for so long that I’ve made myself resistant to any changes that might result from relatively short-term fluctuations in level of soy consumption.”

I have three suggestions:

1. While obviously difficult to implement, self experimentation would be more persuasive if the the experimenter was blinded to the different treatments.

2. We should develop better methods for combining the results of many single subject and self experimental designs. Perhaps some form of Bayesian analysis.

3. The results of single subject and self experimental designs should be replicated with larger sample sizes (although they don’t have to be very large) using within subject designs. This will help guarantee the reliability, validity, and  generalizability of the results.

Here is Dr. Greger on the brain effects of tofu:

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Magnesium and brain function

25 Jan

Seth Roberts links to this report in Nature titled “Testing magnesium’s brain-boosting effects.”

This is an interesting result but please note that the research was funded by a pharmaceutical company that might have an interest in the outcome. In addition, the sample size was small. There is a recurring arc for this type of claim; initial studies with small sample sizes show large effects while later, better designed, research finds no or little effect. Best to keep an open mind but be willing to re-evaluate in the face of new evidence.

There is evidence that the modern diet may be deficient of magnesium.

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Language learning tips

19 Sep

Seth Roberts posts some language learning tips from Carl Willat. I liked this one:

“Movies with subtitles. English movies with Chinese subtitles, Chinese movies with English subtitles, or Chinese movies with Chinese subtitles. Especially movies you’ve seen before so you know the plot and have a vague idea what’s being said. Reading and hearing at the same time seems to help your brain get some traction. “

An excuse to watch more Zatōichi movies!

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