Chapter 7: Time Bombs

No one has ever witnessed the passage of a flying Winnebago, and everyone has witnessed the passage of time. So why is it so much easier to imagine the former than the latter? Because as unlikely as it is that a twenty-thousand-pound recreational vehicle could ever achieve sufficient lift to become airborne, a flying Winnebago would at least look like something, and thus we have no trouble producing a mental image of one. Our extraordinary talent for creating mental images of concrete objects is one of the reasons why we function so effectively in the physical world. If you imagine a grapefruit sitting atop a round oatmeal box and then imagine tilting the box away from you, you can actually preview the grapefruit as it falls, and you can see that it will fall toward you when you tilt the box quickly but fall away from you when you tilt the box slowly. Such acts of imagination allow you to reason about the things you are imagining and hence solve important problems in the real world, such as how to get a grapefruit into your lap when you really need one. But time is no grapefruit. It has no color, shape, size, or texture. It cannot be poked, peeled, prodded, pushed, painted, or pierced. Time is not an object but an abstraction, hence it does not lend itself to imagery, which is why filmmakers are forced to represent the passage of time with contrivances that involve visible objects, such as calendar leaves blowing in the wind or clocks spinning at warp speed. And yet, predicting our emotional futures requires that we think in and about and across swathes of time. If we can't create a mental image of an abstract concept such as time, then how do we think and reason about it?

When people need to reason about something abstract, they tend to imagine something concrete that the abstract thing is like and then reason about that instead. For most of us, space is the concrete thing that time is like. Studies reveal that people all over the world imagine time as though it were a spatial dimension, which is why we say that the past is behind us and the future is in front of us, that we are moving toward our senescence and looking back on our infancy, and that days pass us by in much the same way that a flying Winnebago might. We think and speak as though we were actually moving away from a yesterday that is located over there and toward a tomorrow that is located 180 degrees about. When we draw a time line, those of us who speak English put the past on the left, those of us who speak Arabic put the past on the right, and those of us who speak Mandarin put the past on the bottom. But regardless of our native tongue, we all put the past someplace—and the future someplace else. Indeed, when we want to solve a problem that involves time—for instance, "If I ate breakfast before I walked the dog but after I read the newspaper, then what did I do first?"—most of us imagine putting three objects (breakfast, dog, newspaper) in an orderly line and then checking to see which one is furthest to the left (or right, or bottom, depending on our language). Reasoning by metaphor is an ingenious technique that allows us to remedy our weaknesses by capitalizing on our strengths—using things we can visualize to think, talk, and reason about things we can't.

Alas, metaphors can mislead as well as illuminate, and our tendency to imagine time as a spatial dimension does both of these things. For example, imagine that you and a friend have managed to get a table at a chic new restaurant with a three-month waiting list, and that after browsing the menus you have discovered that you both want the wasabi-encrusted partridge. Now, each of you has sufficient social grace to recognize that placing identical orders at a fine restaurant is roughly equivalent to wearing matching mouse ears in the main dining room, so you decide instead that one of you will order the partridge, the other will order the venison gumbo, and that you will then share them oh so fashionably. You do this not only to avoid being mistaken for tourists but also because you believe that variety is the spice of life. There are very few homilies involving spices, and this one is as good as they get. Indeed, if we were to measure your pleasure after the meal, we would probably find that you and your friend are happier with the sharing arrangement than either of you would have been had you each had a full order of partridge to yourselves.

But something strange happens when we extend this problem in time. Imagine that the maître d' is so impressed by your sophisticated ensemble that he invites you (but alas, not your friend, who really could use a new look) to return on the first Monday of every month for the next year to enjoy a free meal at his best table. Because the kitchen occasionally runs short of ingredients, he asks you to decide right now what you would like to eat on each of your return visits so that he can be fully prepared to pamper you in the style to which you are quickly becoming accustomed. You flip back through the menu. You hate rabbit, veal is politically incorrect, you are appropriately apathetic about vegetable lasagna, and as you scan the list you decide that there are just four dishes that strike your rapidly swelling fancy: the partridge, the venison gumbo, the blackened mahimahi, and the saffron seafood risotto. The partridge is clearly your favorite, and even without a pear tree you are tempted to order twelve of them. But that would be so gauche, so déclassé, and what's more, you would miss the spice of life. So you ask the maître d' to prepare the partridge every other month, and to fill in the remaining six meals with equal episodes of gumbo, mahimahi, and risotto.

You may be one snappy dresser, mon ami, but when it comes to food, you have just cooked your own goose. Researchers studied this experience by inviting volunteers to come to the laboratory for a snack once a week for several weeks. They asked some of the volunteers (choosers) to choose all their snacks in advance, and—just as you did—the choosers usually opted for a healthy dose of variety. Next, the researchers asked a new group of volunteers to come to the lab once a week for several weeks. They fed some of these volunteers their favorite snack every time (no-variety group), and they fed other volunteers their favorite snack on most occasions and their second-favorite snack on others (variety group). When they measured the volunteers' satisfaction over the course of the study, they found that volunteers in the no-variety group were more satisfied than were volunteers in the variety group. In other words, variety made people less happy, not more. Now wait a second—there's something fishy here, and it isn't the mahimahi. How can variety be the spice of life when one sits down with a friend at a fancy restaurant but the bane of one's existence when one orders snacks to be consumed in successive weeks?

Among life's cruelest truths is this one: Wonderful things are especially wonderful the first time they happen, but their wonderfulness wanes with repetition. Just compare the first and last time your child said "Mama" or your partner said "I love you" and you'll know exactly what I mean. When we have an experience—hearing a particular sonata, making love with a particular person, watching the sun set from a particular window of a particular room—on successive occasions, we quickly begin to adapt to it, and the experience yields less pleasure each time. Psychologists call this habituation, economists call it declining marginal utility, and the rest of us call it marriage. But human beings have discovered two devices that allow them to combat this tendency: variety and time. One way to beat habituation is to increase the variety of one's experiences ("Hey, honey, I have a kinky idea—let's watch the sun set from the kitchen this time"). Another way to beat habituation is to increase the amount of time that separates repetitions of the experience. Clinking champagne glasses and kissing one's spouse at the stroke of midnight would be a relatively dull exercise were it to happen every evening, but if one does it on New Year's Eve and then allows a full year to pass before doing it again, the experience will offer an endless bouquet of delights because a year is plenty long enough for the effects of habituation to disappear. The point here is that time and variety are two ways to avoid habituation, and if you have one, then you don't need the other. In fact (and this is the really critical point, so please put down your fork and listen), when episodes are sufficiently separated in time, variety is not only unnecessary—it can actually be costly.

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Excerpted from Stumbling on Happiness by Daniel Gilbert Copyright © 2006 by Daniel Gilbert. Excerpted by permission of Knopf, a division of Random House LLC. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.