Should you peel bananas from the bottom up?

My friend Petal peels her bananas from the bottom. Well, it's the top, actually, since bananas grow upside down. Come to think of it, that's not quite right either—bananas grow the way they grow, which should be right-side up by definition, even if we think of them as upside down. So let me start over. Petal peels her bananas from the end without the stem.
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I mentioned as much at the lunch table last week and triggered a firestorm of debate that has put several research careers on hold and seriously jeopardized the marriage of at least one colleague who, in his single-minded pursuit of truth, has refused for over a week to talk about anything other than the pros and cons of alternative peeling methods. As of this writing, he and his wife have reached an uneasy truce that prohibits him from ever again mentioning the word "banana" in the marital household.

Petal's method is counterintuitive and thus instantly appealing to economists, who love nothing more than to overturn conventional wisdom. Multiple experiments (well, two experiments, actually, since we only had two bananas) quickly convinced a majority of the department that Petal's way is—surprisingly—easier than the traditional method, though the econometricians thought you'd need to test at least 30 bananas to report that result with confidence. The labor economists immediately resolved to apply for a grant.

The same experiments turned up a remarkable pro-Petal instance of the Law of Unexpected Consequences regarding those long stringy things on the sides of the banana that you peel off after you remove the skin. According to our two experiments, peeling from the non-stem end greatly increases the chance that those strings will stick to the skin and come away with it, obviating the need to remove them separately. The attendant reduction in labor input has been particularly persuasive to the development economists, who have also pointed to potential productivity gains from using the stem as a handle.

In the anti-Petal camp, we have the theorists who argue that peeling from the stem end must be optimal because that's what people do. But Petal counters—and indeed this is her clincher argument—that monkeys do it her way (though I think it would be more accurate to say that she does it the monkeys' way) and monkeys are the real experts. In response, my colleague, Mark Bils, who bristles whenever anyone argues that Europeans save more than Americans and therefore Americans must not save enough, is vociferously unmoved by the argument that if we differ from monkeys, the monkeys must be right.

The other major argument that's emerged in favor of the traditional approach is that bananas are more likely to be bruised near the non-stem end. If you peel from the stem, you can eat down to the bruise and throw the rest away, whereas if you peel from the non-stem, you're immediately faced with removing the bruise and figuring out what to do with it. Monkeys, who eat the bruised parts, don't have to worry about this issue.

But my friend Tara, who takes Petal's side, argues thusly (and this is verbatim because I copied it over instant messenger): "Well, the reason they're bruised at the bottom is that we're a top-centric society. When we stock bananas at the market, or select them as consumers, we handle them from the top and plunk them down on their bottoms." The point being that if we all ate from the bottom, the bananas would be handled differently and the bruises would be on the top. (I've fallen back into the top/bottom terminology in deference to Tara, who is trained in film studies and hence unlikely to be comfortable with technical terms like "stem.") To recast Tara's point in terms my colleagues will find most meaningful, we've been analyzing bruises in a partial equilibrium context—taking their location as given—while ignoring the crucial general equilibrium issue of how that location is determined.

Since the phrase "You've ignored the general equilibrium issues" is every economist's all-purpose putdown, and a safe comment to make in pretty much any seminar where you've been jolted out of your sleep and are expected to make a salient remark, it's a little embarrassing that we needed Tara to point out the general equilibrium aspects of banana peeling. In our defense, Tara is an ace computer programmer and not at all your average film studies major.

Much additional work remains to be done. Some of us have launched investigations of subtler issues, such as whether the optimal method of peeling might vary with the ripeness of the banana. So far, there are only two findings I can report with any real degree of confidence. First, economists have a predictable and weak sense of humor. (No fewer than three of my colleagues independently "observed" that if you open from the bottom, the banana will fall out.) Second, if you take an economist—any economist—and give him a banana to hold by the stem and eat from the other end, he really will bear a remarkable resemblance to a chimpanzee.

Unorthodox banana habits may be more common than is generally recognized. In graduate school, I knew a guy (now a mathematical biologist of some prominence) who always split his bananas down the middle and scooped out the seeds, which he discarded. ("I hate banana pits!" he was once heard to remark.) Further field work might uncover even more bizarre behaviors, but that's a job for anthropologists, not economists. Our time is much too valuable.