Matthew Rognlie when he was an undergraduate at Duke, before going to the Ph.D. program in economics at MIT. Here is Matt’s blog.

I have been very impressed with Matthew Rognlie ever since our debate  “Sticky Prices vs. Sticky Wages.” In addition to my being pleased with that debate, it is one of the most popular posts on supplysideliberal.com and had this wonderful review from Simon Wren-Lewis: 

Yet debates among macroeconomists about whether and why wages are sticky go on. As this excellent example (I’ve been wanting to link to it for some time, just because of its quality) shows, they are not just debates between Keynesians and anti-Keynesians, so I do not think you can put this all down to some kind of ideological divide.

So I was delighted to get this email from Matt, which he gave me permission to share with you, after light editing.

Like many others, I enjoyed your and Noah’s article on math learning. In general, I’ve found that most students are puzzlingly quick to conclude that their failure to understand some concept is due to some innate ability, even when it’s hardly plausible that there is any kind of innate barrier. My favorite example of this comes from my high school chemistry class, where I remember talking with one of my classmates about studying for the big exam, and when the time came to talk about some class of reactions she said “oh, I’m not very good at that type of reaction”. And it wasn’t “I keep forgetting that part, so I need to study it more” - the vibe was more “I am just not talented enough to figure out that part of the class, so I’m going to write it off and spend my time elsewhere”.

I remember thinking that this was totally insane - she had mastered all kinds of very similar material in the class, and there was no reason why this particular material should be any more difficult. Even if we do have sizable innate differences in various high-level cognitive skills (memory for facts, memory for ideas, analytical skills, etc.), it is inconceivable that these differences could be so fine-grained that they would prevent her from learning about reactions B, D, and F when she already understood the very similar A, C, and E. Instead, clearly what had happened was that some tiny ambiguity in the presentation of B, D, and F confused her, and with a little more time and exposure she could have resolved it. And it wasn’t that she was unwilling to devote this time due to laziness. Instead, she honestly believed that there was something fundamental barring her from ever understanding this part of the course.

In that case, it was easy for me to see that her belief was ridiculous, but in all honesty I’ve displayed the exact same pattern on many instances. So many times I’ve seen references to some unfamiliar and mysterious concept of math or economics, and nearly written it off as something I’d need ages to understand - and then, when I finally decide to just learn it, I realize that the basic idea is really quite simple. And now, even though intellectually I know that it is very unlikely that any particular concept I encounter is beyond me, it can be very difficult to shake the attitude “oh, X is so confusing, that’s just a hopeless dead zone for me”. I suspect that many students who struggle with math have a much more pervasive and crippling case of the same basic mental block.

One amateurish theory of mine is that the young are better than the old at learning in large part because they are less susceptible to this mental block. This is related to my wife’s theory that the young are better at learning languages because they are less reserved about charging ahead and trying to speak in a new language. Once someone has already mastered one language, it is easy to become hesitant and neurotic when venturing into a new one - it’s incredibly frustrating to formulate your thoughts in the language of a 2nd grader when you could sound immeasurably more sophisticated in English. Yet this process is essential to learning.

The same is true of math. I’ve encountered many articulate and intelligent people who break down in the face of even elementary math. My theory for these people is that their mathematical ineptitude is driven mainly by fear - they know that they won’t be able to converse in math with nearly the same style and intelligence as in English, and are embarrassed to even try. Over time this attitude reinforces itself.