3. Something New?

Dearest Family and Friends,

Here in California, food grows on trees. It’s amazing. Last month Marvin, who lives down our street, arrived with a shopping bag full of persimmons. “When they come in,” says Marvin, "it's best to harvest right away, before they start to ooze and the animals get ‘em.” I left Marvin’s persimmons on our countertop for two weeks until they were translucent and jelly-soft.

Persimmons are climacteric fruits — a new adjective for most of my readers. Climacteric fruits continue to ripen after they are harvested. These fruits produce ethylene gas that speeds up cellular respiration, releases sugar, and develops flavor. Avocados, bananas and tomatoes also do this — leave them on the counter to ripen. Cherries, strawberries, and citrus don’t — they do fine in the refrigerator. Climacteric foods are still alive after they are picked — something vegetarians may want to consider when they bite into a ripe tomato. Ouch!

As I walk around my neighborhood I see bushes and trees bearing fruits I never encountered in Michigan supermarkets. The stuff finds its way into California groceries, making me feel particularly ignorant as I walk down the aisle with my little shopping cart. What is that? How do you eat it? Does it need to be cooked? The locals are putting it into their carts, so it's probably safe. But maybe it is highly toxic and only used for decoration. I haven’t a clue. 

The other day I encountered jujube fruit in the Berkeley Bowl supermarket — slightly wrinkled brown things about an inch and a half across. $2.50 for a cardboard box-full. Should I buy a box? A young woman was also hesitating in front of the display. 

“How do you prepare them?” I asked. 

“I’ve never tried them,” she confessed. “But they look like they are good for you.” 

Ugh. Another clueless Midwesterner. I should have asked a local. Just because a fruit looks good for you doesn’t mean it's so. Maybe jujube eaters all die young, but the food scientists haven’t noticed because they are busy studying bananas. Jujubes could have the wrong kind of antioxidants or something. Why is grocery shopping so stressful? 

It turns out that Jujubes were first domesticated around 9000 BC. They won’t reach Michigan supermarkets for another millennium, but over the years others have found many uses for the plant: Naturally, in India jujubes are all about the spices. The fruit is dried in the sun, then pounded with tamarind, red chillies, salt, and jaggery. The Chinese use jujubes in their traditional medicine to alleviate stress, as an antiseptic, contraceptive, muscle relaxer, to aid the heart, spleen, lungs, and pancreas, regulate blood pressure, prevent ulcers, speed wound healing, and stimulate the immune system. (You have to love traditional Chinese medicine — one of these applications will someday be found to work, and everyone will say “See — ancient wisdom.”) Since the 8th century, the Japanese have used jujube to make woodcuts for books. Italy has a red alcoholic syrup made from jujube called brodo di giuggiole. Naturally, in Australia jujube is brewed into beer. And in America? The “Jujubes” candy popular in movie theaters — a sweet my contemporaries will remember fondly — originally contained jujube juice! But the plant proved too expensive to reliably source and was replaced with high fructose corn syrup and artificial flavoring. (You have to love American capitalism — its predictability is comforting.)

Of course, I didn’t know any of this when I encountered my first jujube in Berkeley Bowl the other day. I had to make a split-second, high-stakes decision in complete ignorance. 

Deciding whether to try a new fruit turns out to be a difficult problem. Think about it. At my age, there are dozens of fruits I have already tried and already know I like. Some random new fruit I encounter isn’t likely to measure up to the best I have already tasted. And if I spend a day or two eating some new fruit I don’t like, I will eat less of the fruits I enjoy. Humans, after all, can only take in so many calories — eating one food reduces consumption of others. Economists say this makes demand for food inelastic, which is mostly true, although my waistline demonstrates a certain amount of food elasticity around the holidays. So, all-in-all, shouldn't I stick with foods I already know I like? Just eat the low-hanging fruit, so to speak. Forget the jujubes. Right?

But the question turns out to be more complicated than that: If I don’t try any new fruits, I may miss out on one I really, really like — something better than any of the fruits I already know. I would wind up eating lesser fruits for the rest of my life when I could have been savoring something better. Perhaps I should try the jujubes a few times as a test. (It is important to try new foods several times to make sure the original sample was representative. This is particularly true of boxed chocolates and holiday cookies.) So give the jujubes a go, right?

Not so fast, Paul. Trying jujubes might have been the best answer when you were young, but what about now — when you have less time left to enjoy a new fruit you discover? Is it prudent to risk your remaining days on unproven foods? Haven’t you reached a stage in life when you should be investing in government bonds and only eating foods you know? Isn’t that the best way to maximize happiness? 

On the other hand, is life really about maximizing personal happiness? Aren’t we social creatures who seek meaning in something larger than ourselves? I’ve got a lot of fruits under my belt (in a manner of speaking). If I keep trying new ones, some day I am apt to stumble across a fruit that is better than anything I have eaten before — something only someone with my eating experience can recognize as a truly spectacular fruit. And I can share the fruits of my labor with others. My grandchildren will enjoy more fruitful lives than they would otherwise, as will succeeding generations.

My dilemma is emblematic of a general class of problem — the exploit/explore tradeoff. Do I use my existing (but incomplete) knowledge to choose my favorite familiar fruit, exploiting what I already know? Or do I invest my time exploring something new that probably won’t work out, but might be better than anything I have experienced heretofore — some fantastic forbidden fruit? 

Mathematicians have proven that the best approach is to do some of each — some exploiting and some exploring. Most people underexplore, but either extreme is problematic. Virtue, as Aristotle noted, lies in the balance. (You have to love Aristotle – he spent most of his mornings meandering around the agora making stuff up, and we’re still quoting him). There is a measure called the Gittins index that quantifies the potential value of each option when your knowledge about the option is limited. If I bring a supercomputer to the supermarket and do the math, I can know with certainty whether to jump on the jujubes. But it's easier to go with my gut: Do I feel like something new? "Openness to new experiences” is a fundamental personality trait. Some people are more open than others. Maybe societies need exploiters and explorers. 

Right now, I am barreling through Berkeley Bowl passing a bin brimming with “Buddha’s hand” — an improbable yellow fruit sporting a dozen tentacles. It looks like a jaundiced octopus with polydactyly. Can that thing possibly be edible? 

Should I try it?

— Paul

One of Marvin’s persimmons. Not ready to eat — it needed another week to ripen.