Kim Kardashian’s Weight-Loss Secret

OK, it may be a little low-brow to use this headline to draw attention to what behavioral scientists call “precommitment.” But if every supermarket tabloid is convinced that Ms. Kardashian works as head-turner, who is Express Scripts to argue?

It was reported in those tabloids two years ago that the celebrity curbs her temptation to overeat with an unusual trick: when she’s had enough, she spoils the rest of her food by pouring something unpleasant on it — window cleaner, to be specific.

This is the power of precommitment: the intentional imposition of penalties or restraints today to ensure better future behavior.

Individuals and organizations use precommitment strategies all the time. In Homer’s Odyssey, Odysseus had to sail his ship past the Sirens, whose enchanting song lured sailors to their deaths. So before entering those treacherous waters, he lashed himself to the ship’s mast so he could resist the temptation. In this way, his precommitment helped him stay the course.

At Express Scripts, we put precommitment to work in an employee exercise program, in which we let people voluntarily commit to participate in a future walk and help themselves stick to that by signing up in advance to receive an appointment on their calendar and a reminder the day before. This simple change — supporting precommitment with an automated appointment and reminder — more than doubled the number of employees that followed through on their decision to participate in the walking program.

Express Scripts also employs precommitment in a variety of ways to help patients avoid the failures of rationality that keep them from taking their medication as prescribed. One example is signing up for automatic refills through home delivery. Another is Call4Generics, which allows members to precommit to future savings opportunities; when a generic becomes available, we don’t have to reach out to the member in advance to substitute to more cost-effective medication.

Precommitment helps us activate our good intentions. Judging from those tabloid covers, it’s working pretty well for Ms. Kardashian.