Category: Science
The evolution of regionalisms on Twitter
Postings on Twitter reflect some well-known regionalisms, such as Southerners' "y'all," and Pittsburghers' "yinz," and the usual regional divides in references to soda, pop and Coke. But Jacob Eisenstein, a post-doctoral fellow in CMU's Machine Learning Department, said the automated method he and his colleagues have developed for analyzing Twitter word use shows that regional dialects appear to be evolving within social media.
In northern California, something that's cool is "koo" in tweets, while in southern California, it's "coo." In many cities, something is "sumthin," but tweets in New York City favor "suttin." While many of us might complain in tweets of being "very" tired, people in northern California tend to be "hella" tired, New Yorkers "deadass" tired and Angelenos are simply tired "af."
The "af" is an acronym that, like many others on Twitter, stands for a vulgarity. LOL is a commonly used acronym for "laughing out loud," but Twitterers in Washington, D.C., seem to have an affinity for the cruder LLS.
That is from Science Daily, hat tip goes to LanguageHat and the original paper (pdf) is here.
Are IVs Going the Way of the Atlantic Cod?
It's hard to come up with a good instrumental variable (plausible source of exogenous randomization) so when someone does come up with one (e.g. legal origin) it's tempting to want to use it again and again. Unfortunately, as Randall Morck and Bernard Yeung point out in Economics, History and Causation, IVs with more than one use are deeply problematic. If a variable is a good IV for X then it can't also be a good IV for Y without also controlling for X and vice-versa. What this means is that every new use of an IV casts doubt on every previous use. Or as, Morck and Yeung, memorably write:
A Tragedy of the Commons has led to an overuse of instrumental variables and a depletion of the actual stock of valid instruments for all econometricians. Each time an instrumental variable is shown to work in one study, that result automatically generates a latent variable problem in every other study that has used or will use the same instrumental variable, or another correlated with it, in a similar context. We see no solution to this. Useful instrumental variables are, we fear, going the way of the Atlantic cod.
I am not quite so pessimistic, I don't see this as a fundamentally new problem or one specific to IVs. Nevertheless, I appreciate their advocacy for a wide variety of empirical methods as a solution to the over-fishing problem.
Among the alternative methods Morck and Yeung recommend, are event studies and Granger causality. I couldn't help but laugh at the last. But I wholeheartedly applaud their primary recommendation which is greater use of and respect for narrative history.
How to make better decisions?
I never thought of this method:
What should you do when you really, REALLY have to “go”? Make important life decisions, maybe. Controlling your bladder makes you better at controlling yourself when making decisions about your future, too, according to a study to be published in Psychological Science, a journal of the Association for Psychological Science.
Sexual excitement, hunger, thirst–psychological scientists have found that activation of just one of these bodily desires can actually make people want other, seemingly unrelated, rewards more. Take, for example, a man who finds himself searching for a bag of potato chips after looking at sexy photos of women. If this man were able to suppress his sexual desire in this situation, would his hunger also subside? This is the sort of question Mirjam Tuk, of the University of Twente in the Netherlands, sought to answer in the laboratory.
Tuk came up with the idea for the study while attending a long lecture. In an effort to stay alert, she drank several cups of coffee. By the end of the talk, she says, “All the coffee had reached my bladder. And that raised the question: What happens when people experience higher levels of bladder control?” With her colleagues, Debra Trampe of the University of Groningen and Luk Warlop of the Katholieke Universiteit Leuven, Tuk designed experiments to test whether self-control over one bodily desire can generalize to other domains as well.
In one experiment, participants either drank five cups of water (about 750 milliliters), or took small sips of water from five separate cups. Then, after about 40 minutes–the amount of time it takes for water to reach the bladder–the researchers assessed participants’ self-control. Participants were asked to make eight choices; each was between receiving a small, but immediate, reward and a larger, but delayed, reward. For example, they could choose to receive either $16 tomorrow or $30 in 35 days.
The researchers found that the people with full bladders were better at holding out for the larger reward later. Other experiments reinforced this link; for example, in one, just thinking about words related to urination triggered the same effect.
“You seem to make better decisions when you have a full bladder,” Tuk says. So maybe you should drink a bottle of water before making a decision about your stock portfolio, for example. Or perhaps stores that count on impulse buys should keep a bathroom available to customers, since they might be more willing to go for the television with a bigger screen when they have an empty bladder.
The pointer is from Michelle Dawson, although I do not take her to be necessarily endorsing (or rejecting) the results. There is related work here and here (pdf).
I wrote this post with an empty bladder.
Counting and Adding
Very enjoyable lecture on partition numbers. Deep but accessible, especially first half. Hat tip: The Endeavour.
Uncelebrated biographies
Nathan Labenz asks:
This got me thinking: what are the most compelling and informative biographies that remain uncelebrated?
"Uncelebrated by whom?" is of course the follow-up question. Nonetheless I will put forward a few names: Jeremy Bentham, Leo Kanner, Norman Borlaug, Brahms and Stravinsky, Antoine Oleyant, a wide variety of 19th century German chemists, engineers, and scientists (who led a second Industrial Revolution), Montaigne, Thomas Bernhard, various French mathematicians, Simon Newcomb, Ramon Llull, Norbert Wiener, Babbage, and I would even say David Hume.
What are we to make of James K. Polk these days? I am not sure.
Relative to their importance, their lives and exploits don't seem to receive much attention. In general, there are few good books (or movies) about the lives of famous economists. Both Hayek and Friedman still lack good biographies, same with Samuelson and Arrow. Smith, Keynes, and Nash are covered, but how many others? Why aren't there more scintillating biographies of engineers and second-tier scientists? It is harder to find important painters, even of the lower tiers, who have not received adequate biographic attention.
“Age and Great Invention”
This is from Benjamin Jones:
Great achievements in knowledge are produced by older innovators today than they were a century ago. Using data on Nobel Prize winners and great inventors, I find that the mean age at which noted innovations are produced has increased by 6 years over the 20th Century. I estimate shifts in life-cycle productivity and show that innovators have become especially unproductive at younger ages. Meanwhile, the later start to the career is not compensated for by increasing productivity beyond early middle age. I further show that the early life-cycle dynamics are closely related to variation in the age at Ph.D. and discuss a theory where accumulations of knowledge across generations lead innovators to seek more education over time. More generally, the results show that individual innnovators are productive over a narrowing span of their life-cycle, a trend that reduces, other things equal, the aggregate output of innovators. This drop in productivity is particularly acute if innovators’ raw ability is greatest when young.
Hat tip goes to Mike Gibson, read his post.
Here is a Gideon Rachmann column from today, on a similar but not exactly the same question. I agree with his penultimate remark on the division of labor.
*The Great Stagnation*, excerpt
From my new eBook, here is one bit:
I’m also persuaded by the median income numbers because they are supported by related measurements of other magnitudes. For example, another way to study economic growth is to look not at median income but at national income, gdp, or gross domestic product, the total production of goods and services. Charles I. Jones, an economist at Stanford University, has “disassembled” American economic growth into component parts, such as increases in capital investment, increases in work hours, increases in research and development, and other factors. Looking at 1950–1993, he found that 80 percent of the growth from that period came from the application of previously discovered ideas, combined with heavy additional investment in education and research, in a manner that cannot be easily repeated for the future. In other words, we’ve been riding off the past. Even more worryingly, he finds that now that we are done exhausting this accumulated stock of benefits, we are discovering new ideas at a speed that will drive a future growth rate of less than one-third of a percent (that’s a rough estimate, not an exact one, but it is consistent with the basic message here). It could be worse yet if the idea-generating countries continue to lose population, as we are seeing in Western Europe and Japan.
I do not hold the view that relative stagnation will last forever, only that it has lasted for thirty-seven years and that it will not end immediately. Oddly, it is the so-called "economic right" — which complains bitterly about decades of increasing taxes and regulation and litigation and government privilege — which finds such a claim hardest to accept.
You can pre-order the eBook; the Amazon link is here, Barnes&Noble here, $4.00. I offer further information on the book here.
Stata Resources
Here are some Stata resources that I have found useful. Statistics with Stata by Hamilton is good for beginners although it is overpriced. For the basics I like German Rodriguez’s free Stata tutorial best, good material can also be found at UCLA’s Stata starter kit and UNC’s Stata Tutorial; two page Stata is good for getting started quickly.
Christopher Baum’s book An Introduction to Modern Econometrics using Stata is excellent and worth the price. The world is indebted to Baum for a number of Stata programs such as NBERCycles which shades in NBER recession dates on time series graphs–this was a big help in producing graphs for our textbook!–so buy Baum’s book and support a public good.
I have found it hugely useful to peruse the proceedings of Stata meetings where you can find professional guides to using Stata to do advanced econometrics. For example, here is Austin Nichols on Regression Discontinuity and related methods, Robert Guitierrez on Recent Developments in Multilevel Modeling, Colin Cameron on Panel Data Methods and David Drukker on Dynamic Panel Models.
I found A Visual Guide to Stata Graphics very useful and then I lent it to someone who never returned it. I suppose they found it very useful as well. I haven’t bought another copy, since it is fairly easy to edit graphs in the newer versions of Stata. You can probably get by with this online guide.
German Rodriguez, mentioned earlier, has an attractively presented class on generalized linear models with lots of material. The LSE has a PhD class on Stata, here are the class notes: Introduction to Stata and Advanced Stata Topics.
Creating a map in Stata is painful since there are a host of incompatible file formats that have to be converted (I spent several hours yesterday working to convert a dBase IV to dBase III file just so I could convert the latter to dta). Still, when it works, it works well. Friedrich Huebler has some of the details.
The reshape command is often critical but difficult, here is a good guide.
Here are many more sources of links: Stata resources, Stata Links, Resources for Learning Stata, and Gabriel Rossman’s blog Code and Culture.
The Singularity is Near: Understanding Trivia, Not Trivial
*FIxing the Sky: The Checkered History of Weather and Climate Control*
For centuries, farmers in Austria shot consecrated guns at storms in attempts to dispel them. Some guns were loaded with nails, ostensibly to kill the witches riding in the clouds; others were fired with powder alone through open empty barrels to make a great noise — perhaps, some said, to disrupt the electrical balance of the storm. In 1896, Albert Stiger, a vine rower in southeastern Austria and burgomaster of Windisch-Feistritz, revived the ancient tradition of hagelschiessen (hail shooting) — basically declaring "war on the clouds" by firing cannon when storms threatened. Faced with mounting losses from summer hailstorms that threatened his grapes, he attempted to disrupt, with mortar fire, the "calm before the storm," or what he observed as a strange stillness in the air moments before the onset of heavy summer precipitation.
That is from the new and quite good book by James Rodger Fleming. If you are wondering, Windisch-Feistritz is now in Slovenia and it is known as Slovenska Bistrica. It looks like this.
*Foundations of Neuroeconomic Analysis*
That is the new book by Paul W. Glimcher, of NYU, Center for Neuroeconomics. This book is especially strong on how valuation takes place in the mind. At times the book feels as if one has stepped into an alternate universe, in which the subjectivist Mengerian Austrians are now doing neuroeconomics instead…
Should we subsidize or tax research into time travel?
Treat this as a balanced budget question, so it's not about fiscal policy. Alternatively, imagine yourself as a benevolent philanthropist: should you support this area of research if you can do so as a free lunch? Or should you try to hinder it?
I believe no one understands the underlying science much at all. But there is some chance that the old science fiction movies are correct and that by time-traveling you alter the course of history, thereby obliterating the universe we used to have. I'll count that as a net negative, while noting there is some chance we end up with a better universe.
On the plus side, the human race will die out anyway. Time travel seems to yield a fairly safe haven. As disaster approaches, keep going back in time a few days, or decades, and that asteroid will never hit you. This is especially appealing if you are transporting back a body (upload?) which is programmed to be more or less immortal and you can take the technology with you, so as to keep on going back as time progresses.
On one side: immortal life for many of the last humans and thus immortality for the human race. And with time they may learn how to thwart the asteriod. On the other side: some probability of swapping universes.
So should we subsidize or tax research into time travel?
Since I cannot reread Heinlein, I should not read a biography of Heinlein
But I can browse one. William H. Patterson's Robert A. Heinlein: In Dialogue with His Century, Learning Curve 1907-1948, would appear to be definitive. The very thick volume one — over six hundred pages with notes – stops at 1948. It is very well written and engaging and connects Heinlein to broader American history. There is plenty on Heinlein and free love, Heinlein and H.G. Wells, Heinlein in the Navy, Heinlein and Missouri, and many other topics.
Why all the dead animals?
Here's a list of the major cases. Here is a Google Map. From National Geographic, here is a responsible account. Loud noises, fireworks, crashes, and an availability cascade seem to be the major hypotheses under consideration. Cold weather and poisoning and hypoxia have been cited as well. Don't forget the dead fishes and crabs; the world seems slightly more sub-Malthusian than before.
Here is Twitter on #deadbirds. In Germany and Schweiz they are talking about "Vogelsterben" and fog; Schweiz had some previous cases over the last few years. Here is a 2009 report from Western Australia, no one seemed to pay heed at the time. There was talk of poison pesticides. Here are many other reports of group animal deaths.
This guy thinks it is all a strategy to scare people.
I'll chalk it up to two or three different causes, combined with coincidental clustering. Is there betting on how many more cases will surface?
We are less willing to help the victims of man-made disasters
People are more willing to donate money to help victims of natural, as opposed to man-made, disasters. Hanna Zagefka and her team found this is because people generally perceive victims caught up in man-made disasters to be more responsible for their predicament and to be less active in helping themselves, as compared with victims of natural disasters.
There is much more here.