New Teaching Blog!

I have decided to start a new teaching blog called On Learning Curves.  Don’t worry.  I’ll still post for the Crockett because Cody Brown is too awesome.  But this isn’t the right forum for my thoughts on the day to day life of a new teacher.  subscribe and enjoy!


Modern Macro

A really good paper from the president of the Minneapolis Fed.

She Doesn’t Age

You might have seen something about this before, but it’s a bit haunting, isn’t it?

Failures of the Catholic Church: The Girls

The issue of priest misconduct (rape, molestation, sexual abuse of minors) in the Catholic Church is one that reviles us, as it should. Figures who supposedly represent authority, wisdom, and virtue are committing some of the most vile acts humans are capable of. Think about what you’d do if your kid was a victim.

That said, the issue as I’ve heard it in my brief foray into mature thinking being-hood (it’s a word now) has revolved around priest misconduct with boys. This got me thinking in recent months. Something sounded a bit off about this. Why is it that we don’t hear as much about girls? The discussion on news channels, in journal articles, in jokes on late night comedy hours; they always reference boys. Seemingly, this rhetoric needs to change, and instead of talking about boys, we need to talk about girls too, and universally framed, about children.

The reason many people come out about their own terrible experiences with priest misconduct is that others are doing so too. As more and more people speak out, a movement grows, and there is a sense of support in the existence of that movement. It’s hard to speak out if you feel like you’re alone and alienated. But since this issue is somewhat skewed towards discussing one gender over the other, it seems that snowball effect has not been as pronounced with girls, and thus they are more hesitant to reveal their stories and start a sort of healing process.

That snowball effect is picking up. Lots of people are asking the same questions. They’re saying similar things as I am, but better than I am.

Andrew Sullivan has had a whole month of stories about this topic, and again, he’s better at this stuff (Boom boom boom boom boom).

We need to change the sound of this story.

What makes something interesing?

An interesting piece on interestingness.

Apparently, humans find things interesting that are both complex but comprehensible.

The first appraisal is an evaluation of an event’s novelty–complexity, which refers to evaluating an event as new, unexpected, complex, hard to process, surprising, mysterious, or obscure. This appraisal isn’t surprising: Intuition and decades of research show that new, complex, and unexpected events can cause interest. The second, less obvious appraisal is an evaluation of an event’s comprehensibility. Appraisal theories would label this appraisal a coping-potential appraisal because it involves people considering whether they have the skills, knowledge, and resources to deal with an event. In the case of interest, people are “dealing with” an unexpected and complex event—they are trying to understand it. In short, if people appraise an event as new and as comprehensible, then they will find it interesting.

What is the purpose of interest?

Interest’s function is to motivate learning and exploration. By motivating people to learn for its own sake, interest ensures that people will develop a broad set of knowledge, skills, and experience. The need for learning is pressing in infancy. Baby humans are cute but ignorant—they have a lot to learn. Early research on infancy found that exploration, play, and diverse experience enhanced motor and perceptual learning. Beyond infancy, interest is a source of intrinsic motivation for learning. When interested, students persist longer at learning tasks, spend more time studying, read more deeply, remember more of what they read, and get better grades in their classes.

Interest attracts people to new, unfamiliar things, and many of these things will turn out to be trivial, capricious, dangerous, or disturbing. Some people … might understandably see this as a dark side of interest. Nevertheless, it is because unfamiliar things can be harmful that people need a mechanism that motivates them to try new things. One never knows when some new piece of knowledge, new experience, or new friendship may be helpful. Interest is thus a counterweight to feelings of uncertainty and anxiety.

It seems to make sense.  Perhaps this can explain why I spend hours on the internet everyday.


The beauty of e

Better Explained does an interesting piece on Euler’s number.

e is the base rate of growth shared by all continually growing processes. e lets you take a simple growth rate (where all change happens at the end of the year) and find the impact of compound, continuous growth, where every nanosecond (or faster) you are growing just a little bit.

e shows up whenever systems grow exponentially and continuously: population, radioactive decay, interest calculations, and more. Even jagged systems that don’t grow smoothly can be approximated by e.

Just like every number can be considered a “scaled” version of 1 (the base unit), every circle can be considered a “scaled” version of the unit circle (radius 1), and every rate of growth can be considered a “scaled” version of e (the “unit” rate of growth).

So e is not an obscure, seemingly random number. e represents the idea that all continually growing systems are scaled versions of a common rate.

e is really cool.  Pi seems to get all the love from mathematicians for being this mystical irrational number. But e is the mystical irrational number of everyday life!

The economics of war bonds

So I just finished a draft of my paper on the Treasury Department’s campaign to sell war bonds in the Second World War.  The subject interests me because to this day  the campaign is grossly misunderstood.  Most everyone, then and now, believes war bonds were how the government paid for the war.  This reflects the fact that most folk believe the government’s finances work like personal finances.  However when the Federal Reserve has monetary creation powers, the intuitive understanding of war finance breaks down.

From a macroeconomic standpoint, the war bond campaign was anti-inflationary policy.  With the government pumping billions of military expenditures into the pockets of consumers, the Treasury wanted to encourage folk to save this money, rather than spend it on scarce consumer goods.  Basically the Treasury was trying to increase the marginal propensity to save, by issuing savings bonds. Simple right?

Wrong.  The war bond campaign gets interesting on the micro scale.  First off, there is little evidence that consumers actually saved more because of the bond campaign.  The decision to spend or save is tied up in a myriad of of everyday decisions, and it is unlikely that an advertising campaign, however massive, would eliminate the demand to buy.  But the bond campaign plays a bigger role in another market: ie the market for efficacy.  To the vast majority of Americans on the home-front, the second world war was a war of imagination.  Millions of enthused Americans had only a tenuous connection to the war.  The war bond campaign allowed these citizens to feel like they were directly contributing to the war effort. In effect buying and selling war bonds fulifulled consumer demand for feeling useful.

This sounds trite, but considering the bond campaign became the largest selling campaign in history, a market for efficacy became a powerful cultural force.  Throughout the war the bond campaign mobilized 7 million volunteers, just shy of the 8.5 million men in the US army at the time.  The Treasury distributed $300 million ($3.5 billion in 2009 dollars)  in donated war bond ads.  Americans jumped onto the war bond band wagon because the idea of helping to pay for the war made a lot of sense to a consumerist America.  Indeed there truly are markets in everything.

Confederate History Month

Ta-Nehisi Coates has been doing a really interesting series of posts on the civil war for “Confederate History Month”.  He’s been pushing back against the notion that slavery was not the primary cause of the civil war, and uses the secession resolutions adopted by the states as evidence.  Reading through them is interesting, Texas’ and Mississippi’s resolutions are particularly shocking:

Texas this free government *all white men are and of right ought to be entitled to equal civil and political rights* [emphasis in the original]; that the servitude of the African race, as existing in these States, is mutually beneficial to both bond and free, and is abundantly authorized and justified by the experience of mankind, and the revealed will of the Almighty Creator, as recognized by all Christian nations; while the destruction of the existing relations between the two races, as advocated by our sectional enemies, would bring inevitable calamities upon both and desolation upon the fifteen slave-holding states..


Our position is thoroughly identified with the institution of slavery– the greatest material interest of the world. Its labor supplies the product which constitutes by far the largest and most important portions of commerce of the earth. These products are peculiar to the climate verging on the tropical regions, and by an imperious law of nature, none but the black race can bear exposure to the tropical sun. These products have become necessities of the world, and a blow at slavery is a blow at commerce and civilization.

His post “One Drop” is worth a read as well.

Probability and the law

A Dutch nurse, who was convicted of murder in 2003 following a string of suspicious deaths at the hospitals where she worked, has been set free.  It turns out that the jury who convicted her fell prey to something called “the prosecutor’s fallacy”, an error in the application of probability theory.  Andrew Gelman blogged about it a while back, and here’s his explanation:

The big number reported to the court was an estimate (possibly greatly inflated) of the chance that so many suspicious events could have occured with Lucia present if she was in fact innocent. Mathematically speaking, however, this just isn’t at all the same as the chance that Lucia is innocent, given the evidence, which is what the court really wants to know.

To see why, suppose that police pick up a suspect and match his or her DNA to evidence collected at a crime scene. Suppose that the likelihood of a match, purely by chance, is only 1 in 10,000. Is this also the chance that they are innocent? It’s easy to make this leap, but you shouldn’t.

Here’s why. Suppose the city in which the person lives has 500,000 adult inhabitants. Given the 1 in 10,000 likelihood of a random DNA match, you’d expect that about 50 people in the city would have DNA that also matches the sample. So the suspect is only 1 of 50 people who could have been at the crime scene. Based on the DNA evidence only, the person is almost certainly innocent, not certainly guilty.

The political leanings of sports fans