Arguments over which species makes for the best pet are deeply unproductive: Clearly, those with different views are deeply misguided. Turtles, say, are easy: they sit around, chewing slowly. Dogs, say, are difficult: they run around, chewing rapidly. But there is a hidden benefit to some choices, unbeknownst to their owners. It’s the fact that turtles are passive and dogs active that’s the key. The Dog, it turns out, needs to go for walks—and so dog owners get a little bit of exercise every day. And, what is the dog’s absolute favorite activity in the world? Meeting (and sniffing) other dogs, who happen to be attached to humans via their leashes—and so dog owners get a little of socializing every day as well. Research shows that getting a little exercise and chatting with strangers contributes to our well-being. Now, we could just decide: I’m going to go for a walk and chat with new people today. And repeat that to ourselves as we press play on another episode of Breaking Bad. But because dogs importune us with, well, puppy dog eyes, they prompt us in a way that we are unable to prompt ourselves.
Dogs beat turtles because they serve as commitment devices—decisions we make today that bind us to be the kind of person we want to be tomorrow. (The most famous example is Odysseus tying himself to the mast to resist the lure of the sirens—he wanted to hear today, but not be shipwrecked tomorrow.)
Researchers have documented a wide array of effective commitment devices. In one study, would-be exercisers were granted free access to audio versions of trashy novels—the kind they might usually feel guilty about. The commitment device? They were only allowed to listen while exercising at the gym, which increased their subsequent physical activity. In another, shoppers who qualified for a 25% discount on their groceries were given the chance to make their discount contingent on committing to increase their purchase of healthy food by 5%; not only did many commit to “gamble” their discount, but the gamble paid off in actual healthier purchasing. And commitments can even seem irrational. People will agree to sign up for savings accounts that do not allow any money to be withdrawn, for any reason, for long periods of time; they will even sign up for accounts that not only offer zero interest, but charge massive penalties for any withdrawals. Committing to such accounts makes little sense economically, but perfect sense psychologically: People are seeking commitment devices to bind themselves to save.
The decision of which pet to choose seems trivial in comparison to health and finances, but it suggests the broad applicability of commitment devices in everyday life. Thinking of life as a series of commitment devices, of not just wanting to be your ideal self tomorrow but designing your environment to commit yourself to it, is a critical insight from social science. In a sense, most relationships can be seen as commitment devices. Siblings, for example, commit us to experiencing decades-long relationships (for better and for worse, and whether we like it or not). Want to better understand different political viewpoints? You could pretend you are going to read Ayn Rand and Peter Singer—or you can drag yourself to Thanksgiving with the extended family. Want to spend more time helping others? You could sign up to volunteer, and then never show—or you can have a baby, whose importuning skills trump even puppies. And finally, want to avoid pointless arguments? This one isn’t a commitment device, just advice: never discuss pet preferences.