Month: February 2009

Interview with Leonard Mlodinow (part 13)

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ROBERTS Did the psychology stuff grow and grow? Did you add more and more than you expected?

MLODINOW Yes. As I was putting a lot of it in the end I would find other studies that really belonged earlier that I would discover, so I would go back and rewrite the earlier parts to incorporate those studies; that became a very fun part of the book, though. That was maybe the most fun, all the psychology studies that I dug out at the end.

ROBERTS How did it happen? You knew that you wanted to include some psychology and then it turned out to be more interesting than you expected?

MLODINOW In the second half of the book when I was talking more and more about viewing life as a random process that we’re going through and applying the concepts of randomness to what we’re seeing in life, I would just naturally come upon these psychology studies.

ROBERTS What fraction of the psychology you read was in the book? I was impressed that you talked about psychology studies that were really good, whereas most of them aren’t. You did a good job of selection and from teaching I know that you have to read a lot of stuff that isn’t good in order to find the good stuff.

MLODINOW What you see in the book is probably a quarter of the stuff that I read or that I thought of putting in the book. In the psychology studies maybe half of them made it into the book and I think I was good at filtering before I even read by following trails of one study leading to other studies and using either textbooks or compilation conference reports to figure out what would be good and what wouldn’t be so good.

I’m talking about half of the studies where I actually bothered to copy the papers; there are other ones, countless studies, where I would get to the abstract and dismiss it after reading the abstract or one page. That I have no way of counting, that’s just constant; maybe ten times as many. But the ones that I actually got to where I made copies . . . if I like something I will print it out because I just can’t read dozens of pages on the screen and plus I like to sit in cafés and carry it around. I guess I could bring my laptop but I tend to print them out. About half of the ones I bothered to print out I put in the book and then there were countless ones that I just dismissed.

ROBERTS Yes, I see what you mean. How did the book’s structure differ from your original proposal? Did the structure change very much?

MLODINOW Yes; I don’t remember exactly, but it did. The first chapter was not there in the proposal; the proposal started with chapter two. Then I realized that I needed an introductory chapter to really set the stage for why we’re interested in these things so for introductory chapter, which is applications to life, I start by analyzing certain situations in life that I think are surprising that people misinterpret; I thought that was a good lead-in as to why we care about this. Then I went into other chapters about developing the ideas of randomness and a lot of that was similar to the proposal although I put in less about Brownian motion and the actual drunkard’s walk itself than I think it had in there. The last several chapters, I extended the discussion about life; I think the middle part of the book is fairly similar to the proposal but the beginning and the end I expanded greatly on discussions of the everyday world and applications; the psychology was not in the original proposal nearly at the level that it was in the final book.

ROBERTS Yes, I see what you mean.

MLODINOW . . . again, as I start talking about events in the world around us and looking at the psychological components–and I dealt with that, I greatly expanded that part–they were fascinating studies and I was just so interested I just kept putting more and more into the book.

Interview directory.

Yay for Dambisa Moyo!

Seth Roberts6 Comments

Many years ago I wrote to the editors of Spy suggesting they do an article about what happened to the money raised by Live Aid. Dambisa Moyo, an African-born economist/author of a book called Dead Aid, has followed up my suggestion. In an interview, she said this:

MOYO Forty years ago, China was poorer than many African countries. Yes, they have money today, but where did that money come from? They built that, they worked very hard to create a situation where they are not dependent on aid.

SOLOMON What do you think has held back Africans?

MOYO I believe it’s largely aid. You get the corruption — historically, leaders have stolen the money without penalty — and you get the dependency, which kills entrepreneurship. You also disenfranchise African citizens, because the government is beholden to foreign donors and not accountable to its people.

Too bad she wasn’t asked what she thought of Jeffrey Sachs or Bill Gates. As Jane Jacobs once said, it’s a curious thing: you can’t help something unless you love it.

More In another interview, Moyo asks, relative to Bono and Africa, how would Americans feel “if Amy Winehouse started to give the US government advice about the credit crunch? And was listened to?”

Shades of Homeopathy! Peanut Allergy Cured . . . With Peanuts

Seth Roberts2 Comments

Doctors at Addenbrooke’s hospital in Cambridge gave four children tiny doses of peanut flour every day, gradually increasing the dose until now they can eat ten or more nuts a day.

Previously the children would have risked anaphylactic shock or even death if they accidentally ate even a trace amount of peanut.

The team say this is the first time that so-called desensitization treatment has been successful.

From the Telegraph. Notes: 1. No blinding. 2. No control group. 3. Started small (with 4 patients), now doing a larger study (18 patients). 4. Jewish kids in Israel have a 10-fold lower rate of peanut allergies than Jewish kids in the UK, according to a 2008 study. In Israel, peanuts are eaten at an earlier age.

Thanks to Oskar Pearson.

The Power of Amateur Content

Seth Roberts2 Comments

Clay Shirky writes:

Publishers have been telling each other for years that eventually people will tire of being able to produce and share amateur content, rather than just consuming professional content, but the users don’t seem to have gotten that memo.

True. I have never heard a book publisher or editor notice that almost all important books have been written by amateurs. Charles Darwin didn’t write books for a living. Nor did Thomas Paine. Nor did Betty Friedan. I think this is why books have been so influential.

Interview with Leonard Mlodinow (part 12)

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ROBERTS I have some questions about details of the book. What was the hardest part of writing the book? . . . there were no hard parts?

MLODINOW Well, I’m thinking about it and also thinking about how I interpret the word ’hard.’ Usually ’hard’ would mean that you’re struggling with it and I’m not sure I exactly struggled with any particular part, in a sense of . . . with all the negative connotations of the word ’struggle,’ where I’m unsure of victory and battling and becoming exhausted and fear for my life.

I guess the part that comes to mind that I had the most doubts about whether I could get through it was the structure of the book because it weaves together three areas that are historically not that smoothly tied together–probability, statistics and the random processes. Or one united subject, like geometry, that you can see the fairly linear development and here it was more intertwined strands. I did have some trouble at first seeing the segue both in concept and tone of the book, from probability to statistics and at the end when I’m talking more about random processes and very specifically about peoples’ lives. To make that a smooth transition so it doesn’t seem like two books, a book on the concepts and another book on peoples’ lives. There was a lot about peoples’ lives in the earlier parts, too, but in the latter parts of the book, I had less and less actual mathematical concepts and almost solely psychology and sociology and discussion of peoples’ lives. Figuring out exactly how to do that–I do remember struggling with that part–I guess that was the hardest part, I would say.

One other difficult thing was that I went back–when I was talking about the Central Limit Theorem and the Law of Large Numbers–I went back and looked at the very specific work that was done by DeMoivre, Laplace, Gauss etc. That was difficult because what they actually did is not in the form that is often attributed to them today. I went back and tried to disentangle what they actually showed and tried to figure out what they were thinking, rather than just talking about the modern form of the theorem in textbooks and attributing it to them.

ROBERTS I see.

MLODINOW That took a lot of effort to figure out. I actually went back and found some of the original calculations.

ROBERTS In a library somewhere? In a manuscript?

MLODINOW They’re in academic books–there are several academic books, so I found some academic books (academic press books, I mean) that presented their actual calculations. I went through those in order to figure out and explain the differences between what they actually did and what the offshoot of their work looks like today.

Interview directory.

The Staggering Greatness of Homemade Yogurt

Seth Roberts28 Comments

I don’t like that title but it’s true. As I will explain in a later post you can’t trust commercial yogurt makers to provide much bacteria in their yogurt — they actually seem scared of the stuff. So I made yogurt myself. It turned out a lot better than I expected.

I had made yogurt dozens of times. This time, however, I wanted to get as much bacteria as possible so I incubated it about 24 hours instead of about 6 hours. It came out far more sour (due to lactic acid) than ever before. But it wasn’t just really sour (like vinegar); it also had complexity of flavor, creaminess, and a pleasant consistency. It was more sour (tart and tangy are the conventional terms) than any yogurt I’ve ever had. I couldn’t eat a bowl of it; I had to eat it with other food. This may be why commercial yogurt is mild: So you will/can eat more of it at one time.

The yogurt I made is essentially a condiment, although it can be mixed with fruit. It improves almost anything: soup, meat, fish, fruit, string beans, scrambled eggs. (Because almost nothing we eat is sour and almost nothing we eat is creamy.) It is better than other common condiments, such as mustard and chutney, because of its creaminess. It is also far cheaper than other condiments. A small bottle of mustard might cost $3. The same volume of homemade yogurt would cost about 10 cents. (You might need twice or three times as much yogurt to get the same effect.) It is far easier to make than other condiments. And, above all, I suspect it is infinitely better for your health. Mustard has few bacteria. If you complexify and sour your food with mustard, you are essentially chewing ice.

Because of subsidies, milk in California is extremely cheap. Ordinary milk, to me, is nearly worthless; I never buy it. Now, with little effort, this very cheap product that I have completely ignored is the source of something like liquid gold — at least, if you like good-tasting food and health.

Recipe. I took a gallon of whole milk, mixed it with 2 cups of powdered milk, heated it at about 200 degrees F. for 10-20 minutes (I’m unsure if this step is necessary), cooled it down to 130 degrees F., added 1/2 cup of starter (from other yogurt), and then incubated it in my oven at about 110 degrees F. for about a day. I divided the mixture into four glass containers. Although the lowest possible setting on the oven is “WARM”, which was too hot, the thermostat actually works at lower temperatures. I set it below WARM and used a room thermometer to adjust the setting so that the temperature was about 110 degrees. (The photo above is not mine, incidentally. My yogurt is no longer photogenic.)

Thanks to Saul Sternberg for help with the recipe.

Salt, Fermented Food, and Black-and-White Speak

Seth Roberts4 Comments

In an informative op-ed piece in the New York Times, Michael Alderman, an epidemiologist, questions a government campaign to reduce salt in processed food. His piece raises two (wildly different) questions.

1. Several studies have correlated less salt with worse health. Why? Alderman writes:

Nine [observational] studies, looking at a total of more than 100,000 participants who consume as much sodium as New Yorkers do, have had mixed results. In four of them, reduced dietary salt was associated with an increased incidence of death and disability from heart attacks and strokes. In one that focused on obese people, more salt was associated with increased cardiovascular mortality. And in the remaining four, no association between salt and health was seen.

And in the one experimental study that Alderman knows of, “the group that adhered to a lower sodium diet actually suffered significantly more cardiovascular deaths and hospitalizations than did the one assigned to the higher sodium diet.”

Those are useful facts. Alderman gives a few possible explanations. Here’s another one: Several popular fermented foods, including sauerkraut, buttermilk, miso, and cheese, are high in salt, and fermented foods protect against heart disease. I haven’t read the experimental study Alderman describes but it is unlikely that the two groups in that study ate food that was the same in every way except for salt content. What probably happened is that one group was instructed to choose a low-salt diet and the other group wasn’t. The low-salt group ate less salt in part by avoiding high-salt fermented foods (such as cheese).

2. Alderman writes:

[Observational] research can justify action only when multiple studies produce consistent, robust findings across a wide range of circumstances, as the research on tobacco and lung and cardiovascular health has done.

The puzzle is why he writes like this, which I find irritating. Most of the editorial is good, which makes this lapse especially interesting. I call this black-and-white speak, talking as if something complex was black and white and — always associated with this — people on one side are better than people on the other side. In my professional life, I hear black-and-white speak from some statisticians, who divide analyses into “correct” and “incorrect.” According to them you should analyze your data by following a set of black-and-white rules. Here is a less-irritating version of Alderman’s statement:

Successful public health campaigns have been built on observational studies but in the best-known case — the danger of smoking — the findings were consistent and robust across a wide range of circumstances.

See: no need to moralize. Alderman’s statement, of course, is just one example of something very common.

Ben Casnocha on another example of moralizing in the Times.

The Unfortunate Saveur 100

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Every year Saveur magazine has a list of 100 “favorite people, places, and things.” This year’s list is the “home cook edition” — meaning related to home cooking. Only one entry is about fermented food: making wine vinegar, which takes 2 months.

Given that there are hundreds of fermented foods, many much easier to make, this is unfortunate — just as bad as Paul Goldberger, the New Yorker‘s architecture critic, ignoring green buildings on his list of the top ten buildings of 2008. (A museum with a garden on its roof doesn’t count. Green building is about better houses and businesses.)

Pagophagia and the Umami Hypothesis

Seth Roberts2 Comments

Pagophagia is an eating disorder where you chew a lot of ice. A friend of mine had it. After she discovered she loved crunching ice cubes, she started going through several trays of ice cubes per day. A trip to Russia, where ice cubes were unavailable, was highly unpleasant. Eventually my friend learned that pagophagia is caused by iron deficiency. When she started eating more iron, her ice craving went away.

Why do we work this way? The evolutionary reason, I think, is that in the ancient world where this tendency evolved, a desire to crunch something was usually satisfied by crunching bones. After you discovered how pleasant it was to crunch bones, you sought them out. Bone marrow is high in iron. Crunching those sought-out bones increased your iron intake.

The umami hypothesis says that we like umami tastes, sour tastes and complex flavors so that we will consume more harmless-bacteria-laden food (which keeps our immune system on its toes). In the ancient environment where these tendencies evolved, in other words, a desire to eat food with these characteristics led us to eat bacteria-laden food. At the Fancy Food Show, I met a maker of sparkling tea who was unable to get enough complexity without using bacteria.

Just as a person with pagophagia chews ice, most of us do one or more of these:

  • add monosodium glutamate (e.g., Accent) for umami taste
  • add vinegar for sourness (I put a few drops of vinegar in coffee-like drinks)
  • add many spices for complexity

The result, I suspect, is that most of us have immune systems with plenty of room for improvement. I stopped getting easy-to-notice colds when I started sleeping better so the high frequency of reported colds (the average American adult gets about three per year) may be a sign that this is true.

Interview with Leonard Mlodinow (part 11)

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ROBERTS I think that if you take the different things that happened to you and you measured their effect, the effects will have a power-law distribution. A tiny number will have a huge effect . . .

MLODINOW Yes.

ROBERTS . . . and a large number will have very little effect. But I guess you could shift the slope of that power-law distribution if you were smart. My research with rats has involved measuring how long they hold the bar down when they press the bar and it turns out that has a power-law distribution.

MLODINOW That’s interesting. Why is it that they hold it down with a power-law distribution rather than, let’s say, a normal distribution?

ROBERTS Why? I think it’s because the way the cerebellum is constructed. I think it has to do with . . . the brain is a network and it’s much easier to get a power-law distribution out of a network than out of a non-network and it’s revealing of the mechanism that produces the bar presses. It’s revealing that it comes from a very networked structure and a little bit more than that, too. It’s not only networked, it’s also chain reactioning and it sheds some light on the mechanism that’s producing the bar presses and that mechanism is not so far from what we see in the cerebellum, which has these incredible density of neurons, highly interconnected neurons. So that’s the connection.

MLODINOW Interesting.

ROBERTS That’s the best I can say as to the why. Clearly evolution designed the brain to solve the problems that animals encounter and why does the cerebellum have the structure it does? Because this power-law distribution is a good idea. Normal distribution is probably too conservative, whereas the power-law distribution is . . . every now and then it’s searching much more widely.

MLODINOW Searching for . . . to see if holding it down less or more amount of time will have any effect, so the power-law you will have some of those explorations into holding it down not long or extra long and therefore sometimes discover something new, rather than really more narrow . . . in a narrow band holding it down a certain number of milliseconds or whatever.

ROBERTS I would guess that the brain has been shaped to produce the power-law distribution in those operations and I think there’s probably other patterns of variability in other aspects of behavior but this is the one we measured.

Interview directory.