Month: February 2013

Teaching With or Against Human Diversity

Seth Roberts1 Comment

Mark Edmundson, a professor of English at the University of Virginia, defended traditional lectures in a New York Times op-ed titled “The trouble with online education”. He described how he teaches. When he teaches, he fails to

1. Pay attention to what students want to learn.

2. Treat different students differently (beyond giving them different grades).

A few weeks ago, I described how doing these two things made teaching much easier. It’s like swimming with or against the current. You can take advantage of human diversity (my approach) or you can ignore it (Edmundson’s approach), which means fighting against it.

 

 

Assorted Links

Seth Roberts2 Comments

Consistent- versus Inconsistent-Handed Predicts Better than Right- versus Left-Handed

Seth Roberts9 Comments

At Berkeley, Andrew Gelman and I taught a freshman seminar about left-handedness. Half the students were left-handed. We did two fascinating studies with them that found that left-handers tend to have left-handed friends. I kick myself for not publishing those results, which I bring up in conversation again and again.

After the class ended I got a call from a journalist who was writing an article about ridiculous classes. I told him the left-handedness class had value as a way of introducing methodological issues but all I cared about was that his article be accurate. He decided not to include our class in his examples.

Stephen Christman, who got his Ph.D. from Berkeley (and did quirky interesting stuff even as a graduate student), and two colleagues have now published a paper that is a considerable step forward in the understanding of handedness. They argue that what really matters is not direction of handedness but the consistency of it. The terms left-handed and right-handed hide a confounding. Right-handers almost all have very consistent handedness (they do everything with the right hand). In contrast, left-handers much more often have inconsistent handedness: they do some things with the left hand, some with the right. I am a good example. I write with my right hand, bat and throw left-handed, play tennis left-handed, ping-pong right-handed. In fact, I am right-wristed and left-armed. When something involves wrist movement (writing, ping-pong) I use my right hand. When something involves arm movement (batting, throwing a ball, tennis), I use my left hand. Right-handers are much more similar to each other than left-handers.

Christman and his co-authors point to two things: 1. When you can get enough subjects to unconfound the two variables, it turns out that consistency of handedness is what makes the difference. Consistent left-handers resemble consistent right-handers. 2. Consistency of handedness predicts many things. Inconsistent-handers are less authoritarian than consistent-handers. They show more of a placebo effect. They have better memory for paragraphs. And on and on — about 20 differences. It isn’t easy to say what all these differences have in common but maybe inconsistent-handers are more flexible in their beliefs. (Which would explain the friendship findings in our handedness class.)

I think about these differences as another example of how every economy needs diversity and our brains have been shaped to provide it, one idea underlying my theory of human evolution. Presidents of the United States are left-handed much more than the general population. For example, Obama is left-handed. The difference between Presidents and everyone else is overwhelming and must mean something. Yet left-handers die younger. I would say that in any group of people you need a certain fraction, not necessarily large, to be open-minded and realistic. That describes inconsistent-handers (who are usually left-handed). These people make good leaders because they will respond to changing conditions. People who are not open-minded make good followers. Just as important as realism is cooperation, ability to work together toward a common goal.

 

Bitter Pill: Why Medical Costs Are Killing Us by Steven Brill

Seth Roberts23 Comments

Steven Brill has a great article in Time called Bitter Pill: Why Medical Costs are Killing Us. I found it nauseating and terrifying — and I have health insurance. It is nauseating that helpless sick people are billed huge amounts of money that bear little relation to costs. It is terrifying that our government has failed to protect us from this.

Brill’s article is about the details of health care costs in America, especially hospital costs. Markups are huge. One example is a test strip for measuring blood sugar. The patient was charged $18 for each strip. On Amazon, the strips cost $0.50 each. The patient had no choice and was not told the wildly-inflated price. Brill gives many examples of similar markups. Hospitals, including nonprofit hospitals, are large prosperous businesses with very well paid CEO’s (e.g., $1 million/year). Yet Americans pay far more for health care than people in any other country and, judged by life expectancy, get worse results than people in about 40 countries. Brill’s article begins to explain the discrepancy.

Asked to explain their prices, many hospitals refused. One of them, MD Andersen in Houston, gave a statement that Brill quotes in part:

The issues related to health care finance are complex for patients, health care providers, payers and government entities alike . . . MD Anderson’s clinical billing and collection practices are similar to those of other major hospitals and academic medical centers.

Judging from the widespread refusals to explain and answers like this (“everyone does it”), the prices are indefensible.

The term stagnation — America is in the grip of profound stagnation — may be misleading because it makes it sound like things are staying the same. People point to a lack of increase in the median income over the last 30 years as indicating “stagnation”. Beneath stagnation is problems stacking up unsolved. (When they are solved, spread of the solutions produces an increase in income.) The problems aren’t staying the same: They’re getting worse. Health care costs are a good example. Health care costs have gone up faster than inflation for a long time, with plenty of signs that the American excess (the difference between what Americans pay and what everyone else pays) is completely wasted. (Or worse, given the many bad effects of drugs, surgery, and other high-tech medicine.) The American excess isn’t trivial, so median income, adjusted for it, has been going down for a long time, over the same period of time that median income in almost every other country has gone up. Quite a comment on the quality of our government.

As Brill says, the health care debate has been about who will pay? The question are prices too high? has been ignored. Jon Stewart said, “This should be a Silent Spring moment.”

Progress in Reducing Acne

Seth Roberts8 Comments

A new study has found that persons with Laron Syndrome (a kind of dwarfism) get almost no acne. Persons with this syndrome, because of a mutation, are insensitive to growth hormone. As a result, they produce much less IGF-1 (insulin-like growth factor) than normal. When given synthetic IGF, they may develop acne; when the dose is reduced, the acne goes away. The authors say: “The findings suggest that an interaction between IGF-1 and androgens is necessary for the development of acne.” This is great progress because people with Laron Syndrome are different from everyone else in just one tiny way (albeit a tiny way with many consequences).

The first important step in understanding the cause of acne was finding two (“primitive”) groups of people with no acne. This suggested that acne has an environmental cause. There were thousands of differences between the lifestyle of those people and “modern” people, so this was just a start. It was hard to know which differences mattered. The Laron Syndrome finding is consistent with the earlier result (no acne in two groups of “primitive” people) because a “Western diet with [its] high intake of hyperglycemic carbohydrates and insulinotropic dairy over-stimulates IIS” (insulin-like/insulin signaling).

This view predicts that if you replace hyperglycemic foods with foods lower in glycemic index acne should be reduced. This study did that and, indeed, acne decreased (compared to a control group) after ten weeks. The study ended after ten weeks. The patient who reduced his/her glycemic index the most saw the greatest decrease in acne. A second study found the same thing: a low-glycemic-index diet reduced acne. It lasted twelve weeks. With longer follow-up, there might have been even more improvement.

Thanks to Paul Nash.

 

 

 

Celiac Experts Make Less Than Zero Sense

Seth Roberts15 Comments

In the 1960s, Edmund Wilson reviewed Vladimir Nabokov’s translation of Eugene Onegin. Wilson barely knew Russian and his review was a travesty. Everything was wrong. Nabokov wondered if it had been written that way to make sense when reflected in a mirror.

I thought of this when I read recent remarks by “celiac experts” in the New York Times. The article, about gluten sensitivity, includes an example of a woman who tried a gluten-free diet:

Kristen Golden Testa could be one of the gluten-sensitive. Although she does not have celiac, she adopted a gluten-free diet last year. She says she has lost weight and her allergies have gone away. “It’s just so marked,” said Ms. Golden Testa, who is health program director in California for the Children’s Partnership, a national nonprofit advocacy group. She did not consult a doctor before making the change, and she also does not know [= is unsure] whether avoiding gluten has helped at all. “This is my speculation,” she said. She also gave up sugar at the same time and made an effort to eat more vegetables and nuts.

Fine. The article goes on to quote several “celiac experts” (all medical doctors) who say deeply bizarre things.

“[A gluten-free diet] is not a healthier diet for those who don’t need it,” Dr. Guandalini [medical director of the University of Chicago’s Celiac Disease Center] said. These people “are following a fad, essentially.” He added, “And that’s my biased opinion.”

Where Testa provides a concrete example of health improvement and refrains from making too much of it, Dr. Guandalini does the opposite (provides no examples, makes extreme claims).

Later, the article says this:

Celiac experts urge people to not do what Ms. Golden Testa did — self-diagnose. Should they actually have celiac, tests to diagnose it become unreliable if one is not eating gluten. They also recommend visiting a doctor before starting on a gluten-free diet.

As someone put it in an email to me, “Don’t follow the example of the person who improved her health without expensive, invasive, inconclusive testing. If you think gluten may be a problem in your diet, you should keep eating it and pay someone to test your blood for unreliable markers and scope your gut for evidence of damage. It’s a much better idea than tracking your symptoms and trying a month without gluten, a month back on, then another month without to see if your health improves.”

Are the celiac experts trying to send a message to Edmund Wilson, who died many years ago?

Posit Science: More Questions

Seth Roberts2 Comments

Posit Science is a San Francisco company, started by Michael Merzenich (UCSF) and others, that sells access to brain-training exercises aimed at older adults. Their training program, they say, will make you “remember more”, “focus better”, and “think faster”. A friend recently sent me a 2011 paper (“Improvement in memory with plasticity-based adaptive cognitive training: results of the 3-month follow-up” by Elizabeth Zelinski and others, published in the Journal of the American Geriatrics Society) that describes a study about Posit Science training. The study asked if the improvements due to training are detectable three months after training stops. The training takes long enough (1 hour/day in the study) that you wouldn’t want to do it forever. The study appears to have been entirely funded by Posit Science.

I found the paper puzzling in several ways. I sent the corresponding author and the head of Posit Science a list of questions:

1. Isn’t it correct that after three months there was no longer reliable improvement due to training according to the main measure that was chosen by you (the investigators) in advance? If so, shouldn’t that have been the main conclusion (e.g., in the abstract and final paragraph)?

2. The training is barely described. The entire description is this: “a brain plasticity-based computer program designed to improve the speed and accuracy of auditory information processing and to engage neuromodulatory systems.” To learn more, readers are referred to a paper that is not easily available — in particular, I could not find it on the Posit Science website. Because the training is so briefly described, I was unable to judge how much the outcome tests differ from the training tasks. This made it impossible for me to judge how much the training generalizes to other tasks — which is the whole point. Why wasn’t the training better described?

3. What was the “ET [experimental treatment] processing speed exercise”? It sounds like a reaction-time task. People will get faster at any reaction-time task if given extensive practice on that task. How is such improvement relevant to daily life? If it is irrelevant, why is it given considerable attention (one of the paper’s four graphs)?

4. According to Table 2, the CSRQ (Cognitive Self-Report Questionnaire) questions showed no significant improvement in trainees’ perceptions of their own daily cognitive functioning, although the p value was close to 0.05. Given the large sample size (~500), this failure to find significant improvement suggests the self-report improvements were small or zero. Why wasn’t this discussed? Is the amount of improvement suggested by Posit Science’s marketing consistent with these results?

5. Is it possible that the improvement subjects experienced was due to the acquisition of strategies for dealing with rapidly presented auditory material, and especially for focusing on the literal words (rather than on their meaning, as may be the usual approach taken in daily life)? If so, is it possible that the skills being improved have little value in daily life, explaining the lack of effect on the CSRQ?

6. In the Methods section, you write “In the a priori data analysis plan for the IMPACT Study, it was hypothesized that the tests constituting the secondary outcome measure would be more sensitive than the RBANS given their larger raw score ranges and sensitivity to cognitive aging effects.” Do the initial post-training tests (measurements of the training effect soon after training ended) support this hypothesis? Why aren’t the initial post-training results described so that readers can see for themselves if this hypothesis is plausible? If you thought the “secondary outcome measure would be more sensitive than the RBANS” why wasn’t the secondary outcome measure the primary measure?

7. The primary outcome measure was some of the RBANS (Repeatable Battery for the Assessment of Neuropsychological Status). Did subjects take the whole RBANS or only part of it? If they took the whole RBANS, what were the results with the rest of the RBANS (the subtests not included in the primary outcome measure)?

8. The data analysis refers to a “secondary composite measure”. Why that particular composite and not any of the many other possible composite measures? Were other secondary composite measures considered? If so, were p values corrected for this?

9. If Test A resembles training more closely than Test B, Test A should show more effect of training (at any retention interval) than Test B. In this case Test A = the RBANS auditory subtests and Test B = the secondary composite measure. In contrast to this prediction, you found that Test B showed a clearer training effect (in terms of p value) than Test A. Why wasn’t this anomaly discussed (beyond what was said in the Methods section)?

10. Were any tests given the subjects not described in this report? If there were other tests, why were their results not described?

11. The secondary composite measure is composed of several memory tests and called “Overall Memory”. The Posit Science website says their training will not only help you “remember more” but also “think faster” and “focus better”. Why weren’t tests of thinking speed (different from the training tasks) and focus included in the assessment?

12. Do the results support the idea that the training causes trainees to “focus better”?

13. The Posit Science homepage suggests that their training increases “intelligence”. Was intelligence measured in this study? If not, why not?

14. Do the results support the idea that the training causes trainees to become more intelligent?

15. The only test of thinking speed included in the assessment appears to be a reaction-time task that was part of the training. Are you saying that getting faster on one reaction-time task after lots of practice with that task shows that your training causes trainees to “think faster”?

Update: Henry Mahncke, the head of Posit Science, said that he would be happy to answer these questions by phone. I replied that I was sure many people were curious about the answers and written answers would be much easier to share.

Further update: Mahncke replied that he would prefer a phone call and that some of the questions seemed to him hard to answer in writing. He said nothing about the sharing problem. I repeated my belief that many people are interested in the answers and that a phone call would be hard to share. I offered to rewrite any questions that seemed hard to answer in writing.

Earlier questions for Posit Science.

 

Assorted Links

Seth Roberts10 Comments

More Trouble in Mouse Animal-Model Land

Seth Roberts2 Comments

Mice — inbred to reduce genetic variation — are used as laboratory models of humans in hundreds of situations. Researchers assume there are big similarities between humans and one particular genetically-narrow species of mouse. A new study, however, found that the correlation between human genomic changes after various sorts of damage (“trauma”, burn, endotoxins in the blood, and so on) and mouse genomic changes was close to zero.

According to a New York Times article about the study, the lack of correlation “helps explain why every one of nearly 150 drugs tested at huge expense in patients with sepsis [severe blood-borne infection] has failed. The drug tests all were based on studies in mice.”

This supports what I’ve said about the conflict between job and science. If your only goal is to find a better treatment for sepsis, after ten straight failures you’d start to question what you are doing. Is there a better way? you’d wonder. After twenty straight failures, you’d give up on mouse research and starting looking for a better way. However, if your goal is to do fundable research with mice — to keep your job — failures to generalize to humans are not a problem, at least in the short run. Failure to generalize actually helps you: It means more mouse research is needed.

If I’m right about this, it explains why researchers in this area have racked up an astonishing record of about 150 failures in a row. (The worst college football team of all time only lost 80 consecutive games.) Terrible for anyone with sepsis, but good for the careers of researchers who study sepsis in mice. “Back to the drawing board,” they tell funding agencies. Who are likewise poorly motivated to react to a long string of failures. They know how to fund mouse experiments. Funding other sorts of research would be harder.

In the comments on the Times article, some readers had trouble understanding that 10 failures in a role should have suggested something was wrong. One reader said, “If one had definitive, repeatable, proof that the [mouse model] approach wouldn’t work…..well, that’s one thing.” Not grasping that 150 failures in a row is repeatable in spades..

When this ground-breaking paper was submitted to Science and Nature, the two most prestigious journals, it was rejected. According to one of the authors, the reviewers usually said, ”It has to be wrong. I don’t know why it is wrong, but it has to be wrong.” 150 consecutive failed drug studies suggest it is right.

As I said four years ago about similar problems,

When an animal model fails, self-experimentation looks better. With self-experimentation you hope to generalize from one human to other humans, rather from one genetically-narrow group of mice to humans.

Thanks to Rajiv Mehta.

The Yakult Women of Seoul

Seth Roberts6 Comments

Their name in Korean means Yakult women: street peddlers who sell several probiotic drinks, including Yakult. I encountered them in a Seoul suburb (Bundang) on the way to the subway. During one 15-minute walk, I saw three of them. Other street peddlers in Bundang were often men (selling cookware or socks, for example) but the probiotic sellers were always women. I haven’t seen street peddlers selling probiotic drinks anywhere else. In Japan, Yakult and other probiotic drinks are sold door-to-door but apparently not on the street.

I asked a Korean friend how she (and Koreans in general) got the idea that probiotic drinks are good for health (which I am sure is true). She said she knew it before she went to school and believed she picked it up from TV ads. Apparently these ads are more successful in Korea than elsewhere. General Foods recently paid $9 million to settle a legal case based on Yoplait Yo-Plus ads in America that made similar claims. The lawyers who sued General Foods claimed that healthy people don’t benefit from Yoplait Yo-Plus.

I can think of several reasons that Yakult women exist in Korea but (apparently) nowhere else. Maybe the fact that Koreans eat a lot of kimchi makes them more likely to believe that a probiotic is healthy. Maybe Koreans care more about health than other people. Maybe Koreans are unusually sophisticated about health. Bundang’s density (it is full of tall apartment buildings) is surely one reason, because Yakult women weren’t the only street peddlers. American suburbs, where I almost never see street peddlers, are much less dense. Another certain reason is that Bundang is a wealthy suburb. A third certain reason is that Yakult and similar drinks help you digest lactose. Lactose intolerance is much more common in Asia than elsewhere.

It would be interesting to compare the rate of digestive problems in South Korea versus other countries, especially the United States. I think they are likely to be much less common in South Korea.