Kernel Of Doubt: Testing Math Preference Vs. Corn-Eating Style

By Scott Alexander

In 2010, Ben Tilly of the blog Random Observations wrote Analysis Vs. Algebra Predicts Eating Corn?, which said:

I like learning about odd connections between disparate things. This probably is the oddest example that I know.

Broadly speaking, mathematicians can be divided into those who like analysis, and those who like algebra. The distinction between the two types runs throughout math. Even those who work in areas that are far from analysis or algebra are very aware of the difference between them, and usually are very clear on which their preference is. I’ll delve into this in more depth soon, but for now let’s just take it for granted that this is a well-known distinction, and it has meaning for mathematicians.

Back when I was in grad school there was a department lunch with corn on the cob. Partway through the meal one of the analysts looked around the room and remarked, “That’s odd, all of the analysts are eating corn one way and the algebraists are eating corn another!” Everyone looked around. In fact everyone was eating the corn in one of two ways. One way was to munch over the length of the corn in a straight line, back up, turn slightly, and do another row across. Kind of like how an old typewriter goes. The other way was to go around in a spiral. All of the analysts were eating in spirals, and the algebraists in rows.

There were a number of mathematicians present whose fields of study didn’t make it clear whether they were on the analysis or algebra side of things. We went around and asked, and in every case the way they ate corn matched their preference. Since then I’ve made a point of amusing myself by asking mathematicians I meet whether they prefer algebra or analysis, and then predicting which way they will eat corn. I’m probably up to 40 or so by now, and in every case but one I’ve been able to correctly predict how they eat corn. The one exception was a logician who claimed to be exactly on the fence between the two. When I explained the corn thing to him he looked surprised, and said that he had an unusual way of eating corn. He went in loose spirals! In other words he truly was a perfect combination of algebra and analysis!

If you have even a passing familiarity of probability, it is clear that despite how unbelievable it initially is that the type of mathematics you prefer is connected to how you eat corn, it is pretty much certain that there actually is a very strong connection. If you believe, as I do, that this difference is connected to how we think about other things, then there must be some odd connection between how we like to understand the world and how we eat corn.

The post later went viral on Hacker News, r/math, and Twitter; it was even the subject of a keynote speech at a math conference.

I couldn’t find any record of it being formally tested, so I included two relevant questions in the 2019 Slate Star Codex reader survey:

These were separated by three unrelated questions, so that most participants would not realize that they were meant to be connected. An informal survey of participants suggested that although some of them had read the Tilly article and realized that the survey was testing it, most did not.

8,171 people answered the survey, of whom 2,683 expressed both a math preference and a corn preference. Here’s what I found:

A chi-square test confirmed that there was no significant difference between the two groups.

Is it possible that participants were not mathematically advanced enough to understand the question? Beginner math students could have interpreted “algebra” to mean the sort of high school algebra where you solve for x if x+1=5, and “analysis” to mean analyzing difficult problems. In order to prevent this, I ran the test again, limiting it to people with PhDs in Math (Degree = “Ph D.” & Profession = “Mathematics”). Here are the results:

Again, chi-square test confirmed there was no significant difference between the two groups (and notice also that the non-significant trend is in the opposite of the predicted direction).

Why might my results be so different from Tilly’s? I found a discussion of this question on Quora, where Daniel McLaury gives an answer that rings true to me:

Now, for the only data point I have: I am decidedly an algebraist and not an analyst, and as best as I can recall I might eat corn in either of these ways, or in a combination of both ways, on any given day. I would imagine the same is true of most people.

As to why he gets such consistent answers, I’ll note that when I read the assertion “algebraists do this, analysts do that,” I thought, “Oh, yes, I do eat corn that way.” After thinking a bit more carefully, making the interpretation I describe in the second paragraph, and then envisioning eating corn each way, it became clear to me that I’ve eaten corn both ways. So I imagine this whole thing is some combination of the power of suggestion and, perhaps, a selective memory on the part of the author.

But do some people genuinely eat corn more one way or the other? If so, what determines this? I analyzed this question by gender, race, ethnicity, subethnicity, religion, sexual orientation, social class, neurotype, and political affiliation (I love this dataset so much). I’m not going to do this rigorously because there are too many comparisons and it’s not worth it, but just eyeballing things it looks like eating-in-rows came to America with the earliest English colonists, and eating-in-spirals is more common among more recent immigrant groups, especially Hindu Indians. I don’t have great data for most countries, but the few European countries where I have a decent sample size seem somewhere in between.

I would make a joke about Western linear thinking vs. Eastern cyclic thinking, but I’m worried someone would take me seriously. I have no good explanation for why these groups eat corn the way they do, or why there’s so much variability even within them.

If you want to confirm or expand these results, you can download the original dataset at the bottom of this post.