The mathematical question for Macy (or our would-be dater looking for love) concerns maximizing probabilities. It’s asking how long do you spend sampling options to give the optimum chances of a successful final decision? How many frogs must you kiss to secure your chances of getting a prince?
Mathematicians have given us an answer: 37%. The basic idea is that, if you need to make a decision from 100 different options, you should sample and discard (or hold off on) the first 37. The 37% rule is not some mindless, automatic thing. It’s a calibration period during which you identify what works and what does not. From the rejected 37%, we choose the best and keep that information in our heads moving forward. If any subsequent options beat that benchmark standard, then you should stick with that option to get the best ultimate outcome.
Let’s take an example. Imagine you find yourself single and wanting a relationship (imagination may not be required). You decide you’re going to go on 10 different dates over a few months. The 37% rule tells us you ought to enjoy yourself on the first three — have a laugh and a drink or two — but do not arrange a second date with any of them. You can do better. What the 37% rule tells us is that the next best date you have is the keeper. They are the ones you should try to settle down with.
Brian Christian in his book, Algorithms to Live By: The Computer Science of Human Decisions, uses the 37% rule to help Macy from our opening example. As he writes: “If you want the best odds of getting the best apartment, spend 37% of your apartment hunt (eleven days, if you’ve given yourself a month for the search) noncommittally exploring options. Leave the checkbook at home; you’re just calibrating. But after that point, be prepared to immediately commit—deposit and all—to the very first place you see that beats whatever you’ve already seen. This is not merely an intuitively satisfying compromise between looking and leaping. It is the provably optimal solution.”