Seth Roberts, Guest Blogger (Part III)

My ideas had been written about before. A columnist for the San Francisco Chronicle, call her Person X, is a friend of friends of mine. She interviewed me and wrote about my idea that faces on TV can improve mood. I had no complaints but a year later a friend said, “She made fun of you, Seth” — gentle fun, to be sure — and he was probably right. My work also attracted the attention of Andrew Solomon, who interviewed me for The Noonday Demon: An Atlas of Depression, a great book. I like and admire Andrew. I was quite happy with what he wrote but even I could see that it wasn’t flattering in a normal way. It was flattering to have been mentioned at all.

Person X and Solomon were perfectly good writers. They told the truth. My claims about mood were so non-standard that they were indeed humorous (Person X) and highly alternative (Solomon) — no doubt about it. But Levitt and Dubner would be the most sympathetic audience I could hope for, I suspected, because Freakonomics and my research were similar in certain ways:

1. Popular beliefs questioned. At one point, an alternative title for Freakonomics was Ain’t Necessarily So. I said that breakfast is bad for you and that drinking sugar water causes weight loss.

2. Delayed causality claimed. Freakonomics said that Roe v. Wade caused a decline in crime that began many years later. I claimed that, under the right conditions, seeing faces in the morning causes big changes in mood that begin about 12 hours later.

It was freakishly (and freakin’) lucky for me that these similarities existed, I thought, that someone who had done such research had been empowered, from my point of view, at just the right time.

I met Dubner and Levitt at the Commonwealth Club in San Francisco, where they spoke. Levitt told the audience that when he was a graduate student, personal computers had recently become available. You no longer had to be wealthy to study a big data set. He took advantage of this to study data sets that economists had not previously studied. Last week I had lunch with Stefano DellaVigna, a professor in the Berkeley economics department. I asked him why economics had become much more eclectic — studying a much wider range of questions — over the last 15 years. He said the same thing as Levitt: the availability of PC’s.

Finally I understood. With cheap, small computers it became much easier to study many things, including the large data sets that Levitt uses and the home data that I collect (e.g., my sleep). When I got a computer at home, self-experimentation became much easier. It was much easier to move data 20 feet (bedroom to PC) than 1 mile (bedroom to campus). Moreover, the statistical software on my PC was better than what I had on the computer in my office. With a PC at home, I started to keep much better records of my sleep. Within a year, using statistical graphics that the PC made possible, I found a surprise in my data: A sharp drop in how much I slept at about the same time that I had lost twelve pounds. Telling my students about this led circuitously to a bigger surprise: Breakfast was causing me to wake up too early. With that discovery I began to realize self-experimentation was more powerful than I had thought.

It is another case of delayed causality. About 15 years ago, Levitt started taking advantage of the expanded opportunity that PCs offered: the ability to study large data sets cheaply. He crunched many numbers not previously crunched. After 15 years, there was enough of this new-fangled research, which dealt with everyday issues, to make a book: Freakonomics.

Likewise, about 15 years ago my self-experimentation started making real progress. Via self-experimentation, I could, like Levitt, study many everyday questions that had previously been much harder to study. After 15 years I had enough data to write a (long) paper. I titled it “Self-experimentation as a source of new ideas” – not so different than Ain’t Necessarily So.

PCs are like small, cheap, high-powered telescopes, which Levitt and I pointed not at outer space but at everyday life. One thing they made visible was delayed causality, the everyday equivalent of very faint stars. As in all areas of science, when it became possible to study something for the first time, many popular beliefs turned out to be wrong. Attacks by real-estate agents on Levitt and Dubner are essentially the same as attacks by creationists on evolution. It was not freakish luck that Levitt’s research resembled mine; there was a reason for it.

Note: I wrote the preceding post a week ago, before seeing the article. I failed to realize a third reason to expect sympathetic treatment: Levitt himself had been written about.