Month: May 2012

How I Will Teach Next Semester: Human Evolution and College Teaching

Seth Roberts9 Comments

I have wondered for a long time how to apply my ideas about human evolution to teaching. My theory of human evolution says that specialization and trading are central to human evolution and includes a mechanism that increases diversity of expertise. The more diverse the expertise of you and your trading partners, the more you gain from trading. If I make knives and you make knives, we will gain less from trading than if I make knives and you make baskets.

I also discovered — independently — that the more choice I gave my Berkeley students (junior and senior psychology majors) about what to learn, the more they learned. It was as if they had an internal drive to learn all sorts of different things and the more I allowed that motivation to push and guide them, the more they learned. To see big effects it wasn’t enough to merely give them a wide choice of term paper topics (as many college teachers do). I pushed them out into the “real” (off-campus) world (they couldn’t do a library project) and said learn whatever you want. In this situation they learned an enormous amount. The connection with my theory of evolution was obvious: something inside of them was pushing them to be diverse in what they learned. What they learn = what they will become expert in. What they become expert in = what they will have to trade.

The more I allowed the underlying diversity of my students to be expressed, the more they learned. Yet almost all college classes treat all of the students in the class the same: same material, same assignments, same tests. The diversity of the students — especially the ways they differ from the professor — is a nuisance. So my theory suggests that standard college teaching is greatly at odds with human nature. It assumes one size fits all when that could hardly be more wrong. It should be possible to greatly increase how much is learned by doing a better job of recognizing human nature. My experience so far supports this prediction.

Recently I thought of a new way to deal with diversity among my students. Next semester I will try it. One of the courses I am teaching (at Tsinghua University) is Frontiers of Psychology, with about 25 students. It’s required of freshman psychology majors. Here’s what I’ll do. For the first four or five class periods (one class per week), I’ll cover a wide range of psychological topics, ideas, and methods. There will be reading assignments (e.g., choose one paper out of 30 and do a class presentation) but no grading. Then every student will draw up a list of “learning goals” for the rest of the semester. The goals can be whatever they want (related to psychology). They can read a book, read some articles, collect some data, give a talk to a high school class, whatever. Each goal will have a deadline. The assessment will be binary: goal completed/not completed. Their final grade will depend on how many goals they completed. The goals will be ordered. The further down their list they get, the higher their grade, with each level of completion assigned a grade at the beginning. They will make class presentations throughout the semester about their progress: what they are doing, what they have learned.

For the students, the benefits (compared to conventional teaching) are that (a) they get to learn exactly what they want yet (b) the grading criteria are very clear and (c) they are still motivated to work. For me, the benefits are that it should be a lot easier to judge if a goal has been completed than to grade homework essays, which is what I’ve done recently. Nor will I have to worry about what happens in class each week.

Any comments?

Assorted Links

Seth Roberts2 Comments

Thanks to Craig Fratrik and Bryan Castañeda.

Personal Science is to Professional Science as Professional Science is to Engineering

Seth Roberts3 Comments

A few days ago I gave a talk at Microsoft Beijing titled “The Rise of Personal Science: Discoveries about Acne, Blood Sugar, Mood, Weight Loss, Sleep, and Brain Function.” (Thanks to Richard Sprague, who invited me.) The audience was engineers.

In response to a question, I said that the relationship between personal science and professional science resembled the relationship between professional science and engineering. Cause-effect statements (X causes Y) vary in their degree of plausibility anywhere from zero (can’t possibly be true) to one (absolute certainty). Engineers, professional scientists, and personal scientists tend to work at different places along this scale:

Engineers work with cause-effect relationships at the top of the scale, that are well-established. (For example, Newton’s Laws.) Relationships in which we have total confidence.

Professional scientists like to study cause-effect relationships that are in the middle of the scale of degree of belief: true and false are equally plausible. When both true and false are plausible, you can publish the results no matter what you find. If everyone already agrees that X causes Y, further evidence isn’t publishable — too obvious. If it is highly implausible that X causes Y, professional scientists cannot study the question because a test of whether X causes Y is too unlikely to pay off. If you find that X does cause Y you can publish it but that’s too unlikely. Finding that X does not cause Y is unpublishable (“we already knew that”).

Personal scientists can easily test ideas with low plausibility. First, because personal science is cheap. Many tests cost nothing. Second, because what other people think is irrelevant. (A professional scientist who takes seriously an idea that “everyone knows is nonsense” risks loss of reputation.) Third, because there is no pressure to produce a steady stream of publications. An example of a personal scientist testing an idea with low plausibility is when I tested the idea that standing causes weight loss. I thought it was unlikely (and, indeed, I didn’t lose weight when I stood much more than usual). But I could easily test it. It led me to discover that standing a lot improves my sleep.

Plainly we need all three (engineers, professional scientists, personal scientists). Has anyone reading this heard someone besides me make this point?

I have been shocked — I sort of continue to be shocked — how much I have been able to discover via personal science. But a high rate of discovery makes sense if personal science supplies a necessary ingredient — ability to test low-plausibility ideas — that has been missing.

How Difficult is Chinese? A Tsinghua Professor Complains

Seth Roberts2 Comments

Recently there was a competition for Tsinghua civil engineering majors. Whose structure can support the most weight? And so on. At the end of the competition, a professor handed out prizes to the winners. After the awards ceremony, the professor who had handed out the awards said to a colleague, “I don’t like this job.” His colleague was surprised: What was so bad about handing out awards? The professor explained that the students’ names sometimes included characters so obscure that he didn’t know them. Which was embarrassing.

Medieval Metallurgy, the Evolution of Decoration, and the Shangri-La Diet

Seth Roberts3 Comments

A new BBC series Metalworks! is about the history of British metal working. My theory of human evolution says that decoration — more precisely, our enjoyment of it — evolved because it helped the most skilled craftsmen make a living. Long ago, technology evolved via massive amounts of trial and error, which required subsidy since payoff (discovery with practical value) was so infrequent. It was much easier to discover/learn how to make something that looked better than something that worked better, but the two sorts of discoveries were correlated: trial and error produces both.

The episode on ironwork (The Blacksmith’s Tale) makes explicit how desire for decoration made it easier for the most skilled iron workers to make a living:

[Expert, at 16:50:] “I think decoration entirely depends on the amount of money the patron wanted to spend on that particular object.” [Narrator:] By the end of the 15th Century, wealthy patrons, such as the Church and monarchy, were hand-picking known craftsmen at the top of their game to match a commission’s requirements. When King Edward IV commissioned the Cornish smith John Tresillion to make these Gothic gates at Windsor in 1497, he did so with good reason. . . . [Expert:] “No blacksmith, ordinary blacksmith who was used to making horseshoes, could dream of working to this standard of perfection.”

Quality of decoration is easy to see. It doesn’t matter but it correlates with something that does matter — amount of trial and error (more trial and error, more innovation). We reward decoration to increase innovation.

The Shangri-La Diet derives from a theory of weight control that emphasizes smell-calorie learning. Smell-calorie learning evolved for the same logical reason. Smells don’t actually matter for health. But they are easy to notice and they correlate with things that do matter for health, such as calories. Via smell-calorie learning we learn the correlations. After that the foods that smell best are the ones that contain more calories.

Vitamin D3 in Morning: Moving D3 to Morning Improves Sleep (Story 23)

Seth Roberts3 Comments

Jim Breed has been taking large amounts of Vitamin D3 (5000-10000 IU/day) since 2008. Yet when he switched to taking it in the morning, his sleep quickly improved. Here’s what happened:

I’m a married man, 230-240 pounds over the past 4 years, born in 1957, and I work as an engineer for the Department of Energy in an office. I try to do cardio for thirty minutes four times a week.

In 2008, I began taking 5-10000 IU Vitamin D3 daily. My blood tests:

October 2009 50 ng/ml
August 2010 65 ng/ml
May 2012 84 ng/ml

My doctor said to reduce my intake from 10000 IU to 5000 IU when it hit 84, as he prefers levels under 80.

Prior to beginning the morning D, I took one 5000 IU gel cap two times during the day. I usually took my supplements at breakfast, lunch, and dinner. I might take 5000 at lunch and 5000 at dinner. Since I started taking Vitamin D in 2008, I have not missed a day of work due to illnessk. This is unusual. Throughout grade school, high school, college, and my work for the Federal Government, I have never had a complete year where I wasn’t sidelined by some cold, flu, what have you for an unscheduled absence due to sickness

In November 2011, I started reading posts on your blog about morning D affecting sleep. I tried taking my Vitamin D in the morning — upon awakening, which is usually 6:30 am. Definitely by 8:30 am. Within a week, I noticed two things:

1. I started sleeping all night without waking in the middle of the night. For years, I have had trouble sleeping throughout the night. I usually slept with earphones so I could listen to the radio around 2 am for an hour until I fell asleep again. Once I woke up, it took a lot to get back to sleep. Now, I may stir for a few minutes or get up to use the toilet, but I fall back to sleep very quickly.

2. My bed times became more consistent and earlier. I married my wife in 2005. It had been a consistent source of tension between us that she liked to go to bed earlier than me (10:30 pm for her 11:30 for me). I wasn’t tired. Midnight would have been better for me. Since the morning D, I have consistently beaten my wife to bed. I am just done for the day and ready to go to sleep by 10:30. This is truly a change for the better.

I did not expect these results. I reasoned that since my blood levels were so high, when I took D would not matter. I was surprised to be wrong.

I also found that an unexpected reduction in my dosage screwed up my sleep. This was really exciting. My wife and I traveled to Livermore, CA from our home in KS. She gave me some travel supplement packs that she makes up and it did not have our usual brand of D. Here is how the trip went.

  1. Friday-fly to CA 10,000 iu at waking; great sleep in hotel room
  2. Saturday-travel D; great sleep in hotel room
  3. Sunday-travel D; great sleep in hotel room
  4. Monday-travel D; great sleep in hotel room
  5. Tues-travel D; restless sleep in hotel room. I heard the A/C unit. The bed was uncomfortable. I fell asleep during a meeting with the lights down at work
  6. Wed-travel D; terrible sleep in hotel room. In a meeting at the lab I make a mental note to ask my wife what the travel dosage is.

It turns out that the travel dosage was 1000 IU. I thought it was just a different brand. Definitely, 1000 IU was not enough. I immediately went to Walgreens and got some 5000 IU gelcaps and began taking the 10000 IU upon waking. It took about a week to re-establish my previous restful sleep.

Reducing my dosage from 10000 IU to 5000 IU did not disturb my restful sleep patterns- When my doctor had me cut back to 5000 IU at the beginning of May, I didn’t notice any decrease in restful sleep. If anything, it seems to be better than when I was taking 10000 IU.

Assorted Links

Seth Roberts10 Comments
  • Correlation between fat intake and brain-test scores. “Those women who reported the highest saturated fat intake also had, on average, the worst scores on reasoning and memory tests.”
  • How many iPads does it take to change a textbook market? A perfectly good physics textbook is now available for free download (pdf). The author of the post, a physics professor at William and Mary named Marc Sher, does not understand what’s going on when he refers to “the textbook publishers’ price-gouging monopoly” and their “outrageous practices”. Textbooks cost so much because students can be forced to pay that much. This has nothing to do with publishers, I submit, and everything to do with the power professors have over students. Sher would reply: All the textbooks are expensive. And I say: So what? If students could choose not to buy $200 textbooks, none would be sold. Zero. And future years would see no more $200 textbooks.

Thanks to Jonathan Graehl.

Assorted Links

Seth Roberts11 Comments
  • A good example of how misleading drug-company-sponsored analyses of drug trials can be. Independent reanalysis by Daniel Coyne, a professor of medicine at Washington University in St. Louis, reached opposite conclusions. Good work, Coyne.
  • Coke contains a carcinogen.
  • “I used sunflower seeds to lose weight.” Someone else used them to reduce addictions. The link between the Shangri-La Diet and reduction of non-food addictions (smoking, coffee) fascinates me. People start SLD to lose weight and say they become less addicted to smoking, coffee drinking, and so on. One possibility is that by reducing hunger, SLD reduces discomfort. Addictions gain strength from discomfort, often resemble self-medication.
  • Steve McIntyre replies to Gavin Schmidt’s claim that McIntyre’s beliefs resemble “classic conspiracy theory”. I used to watch a lot of football — when the 49ers won most of their games. (I am a classic fairweather fan.) I get a similar pleasure reading Steve McIntyre’s posts as I did from watching 49er games.
  • Congratulations, UCLA press office! A study that measured the effect of omega-3 by comparing two groups of rats — one gets omega-3, the other doesn’t — is called a study about the evils of fructose (both groups got a high-fructose diet). I am surprised the scientists involved didn’t object to this misrepresentation. The study supposedly shows — according to the press office — that fructose is bad because performance went down when the rats were switched from standard lab chow to a high-fructose diet. Let’s say you start with a diet (standard lab chow) that has a barely adequate amount of omega-3. You feed both groups lab chow for several months. Then you do an experiment in which both groups get 60% of their calories from the lab chow and 40% of their calories from a diet that contains no omega-3. Performance is likely to decline due to insufficient omega-3 no matter what the new diet contains.

Thanks to Tim Beneke.

Usual Drug Trial Analyses Insensitive to Rare Improvement

Seth Roberts4 Comments

In a comment on an article in The Scientist, someone tells a story with profound implications:

I participated in 1992 NCI SWOG 9005 Phase 3 [clinical trial of] Mifepristone for recurrent meningioma. The drug put my tumor in remission when it regrew post surgery. However, other more despairing patients had already been grossly weakened by multiple brain surgeries and prior standard brain radiation therapy which had failed them before they joined the trial. They were really not as young, healthy and strong as I was when I decided to volunteer for a “state of the art” drug therapy upon my first recurrence. . . . I could not get the names of the anonymous members of the Data and Safety Monitoring committee who closed the trial as “no more effective than placebo”. I had flunked the placebo the first year and my tumor did not grow for the next three years I was allowed to take the real drug. I finally managed to get FDA approval to take the drug again in Feb 2005 and my condition has remained stable ever since according to my MRIS.

Apparently the drug did not work for most participants in the trial — leading to the conclusion “no mnore effective than placebo” — but it did work for him.

The statistical tests used to decide if a drug works are not sensitive to this sort of thing — most patients not helped, a few patients helped. (Existing tests, such as the t test, work best with normality of both groups, treatment and placebo, whereas this outcome produces non-normality of the treatment group, which reduces test sensitivity.) It is quite possible to construct analyses that would be more sensitive to this than existing tests, but this has not been done. It is quite possible to run a study that produces for each patient a p value for the null hypothesis of no effect (a number that helps you decide if that particular patient has been helped) but this too has not been done.

Since these new analyses would benefit drug companies, their absence is curious.

The Next Time a Top Economist Predicts Disaster…

Seth Roberts2 Comments

Shortly before Obama took office, many American banks, including the largest ones, were given a huge amount of money by the Federal government (“bailed out”). Why? Because Secretary of the Treasury Henry Paulson, Chairman of the Federal Reserve Ben Bernanke and other economists (not necessarily independent of Paulson and Bernanke) predicted a second Great Depression if they weren’t. I didn’t believe Paulson et al. — their track records of prediction were terrible. They hadn’t foreseen the crisis. Why should I think they knew how to fix it? I believed their predictions of disaster were too confident.

At the time I didn’t know this bit of history:

The blood-curdling threats [now] being issued by Eurocrats should sound familiar to British readers. We went through precisely the same experience 20 years ago, when we were stuck with an over-valued exchange rate in the Exchange Rate Mechanism.

As in Greece, our leaders – all the main parties, the CBI, the TUC, the Bank of England – assured us that leaving the ERM would be disastrous. On September 11, 1992, John Major solemnly told us that withdrawal was ‘the soft option, the inflationary option, the devaluer’s option, a betrayal of our country’s future’.

Four days later, we left the system, and our recovery began immediately. Inflation, interest rates and unemployment started falling, and we enjoyed 15 years of unbroken growth

Those who don’t know the past are doomed to over-trust experts.