Category: Science

Blogs about the professions and what they are like

by  Tyler Cowen in

Richard, a loyal MR reader, writes to me:

For the last couple months I've been following the FemaleScienceProfessorblog (http://science-
professor.blogspot.com/).  It's basically about the professional life of a biology professor.  It's not fascinating or thought-provoking in the way MR is.  Much of the time, it's really rather mundane, which is the whole point.  Reading it, I feel like I know much more about what it's like to be in a professional position much like hers. It's not cluttered with really any other random stuff; every new post that comes in from her, I know what I'm getting.

Here's my request: I'd love to find 5-10 more blogs like this.  I don't even particularly care what professions, but I'd like to get a non-glamorized, relatively even-handed inside view of other professions. I certainly would have loved to have had a few dozen of these to follow when I was trying to make career choices…

This is a good question, but I have nothing to offer.  Would MR readers care to make some suggestions?

Hi, Neanderthal!

by  Tyler Cowen in

A genetic analysis of nearly 2,000 people from around the world indicates that such extinct species interbred with the ancestors of modern humans twice, leaving their genes within the DNA of people today.

The article is here, including a link to the original research, which is published in the highly reputable Nature.  I am not able to evaluate this result, but it does seem newsworthy and also from a reputable source.  Hat tip goes to the ever-excellent The Browser.

Serious question: even if it is true only probabilistically, should I be happy or sad about this news?

The Back-up Plan

by  Tyler Cowen in

The journals of the American Economic Association have started an experiment that acknowledges the reality that papers move from one publication to another — and the system could save authors considerable time, and publications money. In the experiment, authors of papers that are rejected from the flagship journal — American Economic Review — can now opt to have referee reports sent directly to one of four other journals published by the association.

So far it looks like a near-Pareto improvement.  Here is more detail; by the way, editors from sociology and anthropology say that plan wouldn't work in their disciplines, though neuroscience has a reviewing consortium.

Accounting for Carbon Offsets

by  Alex Tabarrok in

Highly complex, difficult to value assets are being evaluated by a handful of firms with strong ties to the financial corporations whose job it is to market those assets to investors around the world.  Sound familiar?

It's not mortgages but carbon offsets and not only are the issues related many of the same players are involved. Harpers has a good piece (subs, try also here (pdf)) with more details than I have seen elsewhere on how the market works.  It's not all bad, as the author, Mark Schapiro shows, the measurement infrastructure that has been created is actually quite impressive, but not enough effort has been put into monitoring.  Here's one good bit:

In this highly specialized new industry, perhaps
a thousand people really understand how
onsite measurement of CDM projects works,
and there is a serious potential for conflicts of
interest. It is not uncommon for validators and
verifiers to cross over to the far more lucrative
business of developing carbon projects themselves–
and then requesting audits from their
former colleagues. Schneider points out that
young university graduates entering the field
commonly spend several years learning the
ropes at DOEs and then “go to work for a carbon
project developer, where they make three
times the salary doing more interesting work.”

These developers–which partner with local
businesses and governments to set up offset projects–
are by and large funded or owned outright
by multinational firms, particularly financial
houses such as JP Morgan Chase, which owns
the biggest developer in the world, Eco-Securities; Goldman Sachs, which has a significant interest in the largest U.S.-based developer,
Blue Source; and Cantor Fitzgerald, which owns
CantorCO2e, another major player….

A revisionist perspective on ADHD

by  Tyler Cowen in

This article is not perfect, but it is much better than most MSM coverage of its topic.  Here is one good paragraph:

That said, some adults with ADHD are highly intelligent, energetic, charismatic and creative, and are able to focus intently on a narrow range of topics that interest them. David Neeleman, the founder of JetBlue Airways, and Paul Orfalea, founder of Kinko's, have spoken out about how the disorder helped them come up with innovative ideas for their corporations, despite their having done poorly in school.

I have tried to track this point through the research literature, but it still seems to me that the way in which ADHD brings a high variance of attention — rather than just jumpy, scatterbrained behavior — is poorly understood.  There is, by the way, some preliminary evidence that ADHD is overrepresented in entrepreneurs.

The iPad

by  Tyler Cowen in

Could this be the medium through which the fabled convergence finally occurs?

Most of all, think of it as a substitute for your TV.

It has the all-important quality of allowing you to bend your head and body as you wish (more or less), as you use it.  By bringing it closer or further, you control the "real size" of the iPad, so don't fixate on whether it appears "too big" or "too small."

The pages turn faster than those of Kindle.  The other functions are also extremely quick and the battery feels eternal.

So far my main complaint is how it uses "auto-correct" to turn "gmu" into "gum."

While I will bring it on some trips, most of all it feels too valuable to take very far from the house.

On YouTube I watched Chet Atkins, Sonny Rollins, and Angela Hewitt.

Note all the categories on this short post!

Attracted to Evil?

by  Alex Tabarrok in

In transcranial magnetic stimulation (“TMS”), a coil of wire is placed near the head. Alternating current flowing through the coil induces a magnetic field with a strength of up to 2.5 teslas (one tesla is 20,000 times the strength of the earth’s magnetic field). The field passes harmlessly through the skull and influences the electrical Brain_magnetsignals passing among neurons in the brain.

(Image and quote from Progress Daily.)

TMS has been used to stimulate or suppress different centers of the brain including those involved with attention, language and memory.   A new paper in PNAS used TMS to disrupt part of the brain involved in judging intention and morality.  Here is a summary:

Magnets can alter a person's sense of morality, according to a new report in the Proceedings of the National Academy of Sciences. 

Using a powerful magnetic field, scientists from MIT, Harvard University and Beth Israel Deaconess Medical Center are able to scramble the moral center of the brain, making it more difficult for people to separate innocent intentions from harmful outcomes….

Magnetic fields made people judge outcomes more than intentions.

The effect was small and temporary but no less disturbing especially if the effect could be made to operate at a distance.  Perhaps the tin-foil-hat-people have had it right all along.

The Slartibartfast Principle

by  Alex Tabarrok in

From Wired:

Canadian poet Christian Bök wants his work to live on after he’s gone. Like, billions of years after. He’s going to encode it directly into the DNA of the hardy bacteria Deinococcus radiodurans. If it works, his poem could outlast the human race.

If it is conceivable, just 57 years after the identification of DNA's structure, for a Canadian poet to imprint his poetry into the DNA of a living organism then isn't it probable that an intelligent designer in the past would have had similar desires and perforce much greater abilities to accomplish the task?

Thus the evidence for intelligent design ought to be readily available in the graffiti of DNA. "Slartibartfast was here," or perhaps "3.14159265," or given what we know of economics, "All rights reserved, MegaCorp. Call for a free estimate."

The fact that we have not found such evidence reduces my belief in intelligent design, although I am not against more investigation.  Indeed, one of the few arguments for god that I have ever given much credence to was the putative discovery of codes predicting future events in the Bible.  A serious paper on this topic was published in Statistical Science in 1994.  The paper was later convincingly rebutted but I still think it was the best evidence ever presented for an intelligent designer. 

Addendum One: Interestingly one of the few people who thought as I did, although coming from a quite different direction, was Nobel prize winner Robert Aumann who early on supported the Bible codes research.  However, after further research, supervised by Aumann, concluded that the paper could not be replicated Aumann returned to his prior view that the codes were improbable.  It's unclear what, if anything, would further shift his prior.

Addendum Two: Steven Landsburg was here yesterday and at lunch suggested that perhaps the great designer's name was in fact 3.14159265…

Gender risk-aversion, using data from chess

by  Tyler Cowen in

Dan Houser sends me a link to this paper, by Christer Gerdes and Patrik Gränsmark:

This paper aims to measure differences in risk behavior among expert chess players. The study employs a panel data set on international chess with 1.4 million games recorded over a period of 11 years. The structure of the data set allows us to use individual fixed-effect estimations to control for aspects such as innate ability as well as other characteristics of the players. Most notably, the data contains an objective measure of individual playing strength, the so-called Elo rating. In line with previous research, we find that women are more risk-averse than men. A novel finding is that males choose more aggressive strategies when playing against female opponents even though such strategies reduce their winning probability.

I am pleased to see that studying chess data is suddenly a "trendy" way to do behavioral economics.  Admittedly one is dealing with an unusual group of subjects.  Yet the quality of the data is high and the stakes are usually high too.  Computers can be used to judge the quality of moves.

The Meaning of Statistical Significance

by  Alex Tabarrok in

Science News has a good piece by Tom Siegfried on statistical significance and what it means.  Siegfried covers a lot of ground including Ioannidis' argument, Why Most Published Research Findings are False, Oomph versus statistical significance, and the meaning of the p-value.  On the latter point, Siegfried writes:

Correctly phrased, experimental data yielding a P value of .05 means that there is only a 5 percent chance of obtaining the observed (or more extreme) result if no real effect exists (that is, if the no-difference hypothesis is correct). 

He then explains why a 5% level of significance doesn't mean that there is a 95% chance that the result could not have happened by chance.

All of this is correct but there is another more common error that Siegfried does not address. Suppose that a researcher runs a regression and gets a coefficient on some variable of interest of 5.2 and a p value of .001. In explaining his or her results the researcher says "a effect of this size would happen by chance alone only 0.1% of the time."  Now that sounds very impressive but it is also misleading.

In economics and most of the social sciences what a p-value of .001 really means is that assuming everything else in the model is correctly specified the probability that such a result could have happened by chance is only 0.1%.  It is easy to find a result that is statistically significant at the .001 level in one regression but not at all statistical significant in another regression with small changes such as the inclusion of an additional variable.  Indeed, not only can statistical significance disappear, the variable can change size and even sign!

A highly statistically significant result does not tell you that a result is robust.  It is not even the case that more statistically significant results are more likely to be robust.

Now go back to Siegfried's explanation for the p-value.  Notice that he writes "Correctly phrased, experimental data yielding a P value of .05…"  Almost everything of importance is buried in those words "experimental data."  In the social sciences we rarely have experimental data.  Indeed, even "experimental data" is not quite right – truly randomized data might be a better term because even so-called experimental data can involve attrition bias or other problems that make it less than truly random.

Thus, the problems with the p-value is not so much that people misinterpret it but rather that the conditions for the p-value to mean what people think it means are really quite restrictive and difficult to achieve.

Addendum: Andew Gelman has a roundup of other comments on Siegfried's piece.

I worry about this

by  Tyler Cowen in

The Russians are not alone in pushing the idea that the next generation of nuclear reactors should have more in common with the small power plants on submarines than the sprawling installations of today.

And this in particular:

The promise of miniature reactors powering homes, offices and schools is still years from being realized. The first Russian design, a pontoon-mounted reactor intended to be floated into harbors in energy-hungry developing countries, is already being built. But most promoters expect small reactors to come online at the end of this decade.

And this:

Some models are tiny. One, for example, would be small enough to fit into a shipping container and would be trucked from site to site, like a diesel generator, except that it would need to be refueled only once every seven years or so.

The opening cost for these "mini-reactors" is expected to run about $100 million.  The full story is here.