Jet Lag, Night Feedings, and Fixed Costs
By Bryan Caplan
Economists usually emphasize marginal analysis. Should a firm make one more pound of steel? Should a shopper spend one more minute looking for a lower price? But economics has just as much to say about all-or-nothing decisions. If a firm has to pay a fixed cost to stay in business, it shouldn’t just weigh the costs and benefits of making another pound of steel. It should also weigh the costs and benefits of making any steel. If a shopper has to pay a fixed cost to get to the store, similarly, he shouldn’t just weigh the costs and benefits of another minute of search. He should also weigh the costs and benefits of going to the store in the first place.
As a generality, this is all pretty obvious. But applying this generality is harder than it looks. Here are two practical decisions where it took me a while to figure out the optimal response to the fixed costs I faced:
1. Jet lag. What’s the best way to cope with jet lag? Most people sleep on the plane, then gradually adjust to the local time once they reach their destination. The problem: It often takes a week for people to get a decent night’s sleep. By the time they’re feeling themselves again, they’re almost ready to go home.
My alternative: Do not sleep on the plane. At all. When you arrive, do not sleep – at all – until a locally normal bedtime. Pay the fixed cost without cheating. When you wake up eight to ten hours later, you will be refreshed and in sync with your new time zone. In exchange for less than a day of sleep deprivation, you will feel fine for the rest of your trip.
2. Night feedings. Newborn infants typically sleep in 2-4 hour blocs. When they wake up, they usually need a new diaper, and almost always want to eat. Most parents handle this by sleeping whenever they get the opportunity, then waking up when the baby starts crying. Many go one step further and “takes turns” for night feedings out of some sense of fairness.
As long as you have two available care providers, the conventional approach is extremely imprudent. What’s the alternative? One care provider should pay the fixed cost to get on a nocturnal schedule. After a day or two, the person on the night shift adjusts to sleeping during the day, allowing the other care provider to sleep through the night without interruption. Instead of “fairly” “sharing the pain,” you’re cleverly slashing the total amount pain down to a manageable size.
Yes, switching to the night shift hurts at first. I should know – I’m going nocturnal for natalism right now! But after a day or two the whole family will feel fine – and you’ll have basic economics to thank.