The Willpower Instinct: How Self-Control Works, Why It Matters, and What You Can Do To Get More of It

GOD WANTS YOU TO LOSE WEIGHT
Can you convince people to exercise and eat more fruits and vegetables by telling them it’s what God
wants? An intervention at Middle Tennessee State University is doing exactly that, with excellent
results. The intervention asks people to consider how self-care and health are important values in
their religion. For example, Christians may be asked to reflect on passages from the Bible such as
“Do not join those who drink too much wine or gorge themselves on meat” (Proverbs 23:20 NIV) and
“Let us purify ourselves from everything that contaminates body and spirit, perfecting holiness out of
reverence for God” (2 Corinthians 7:1 NIV). They are asked to reflect on the behaviors in their own
lives—such as eating junk food or not exercising—that are inconsistent with their professed faith and
values. When they identify a disconnect between their faith and their actions, they are encouraged to
create an action plan for changing that behavior. Believing that losing weight and exercising is what
good Christians do is powerful social proof—far more motivating than getting a stern warning from a
doctor after getting bad results on a cholesterol test.
Mark Ansel, the psychologist who developed this approach, argues that religious communities
should take on more responsibility for supporting behavior change. Places of worship could offer
fitness classes and nutrition talks alongside religious services, and social events should serve
healthier food. He points out that for this approach to work, religious leaders will have to be good
role models. Before they start preaching morning walks, they need to get in shape themselves—and
just like they wouldn’t be caught in a brothel, they’ll need to think twice about stepping into the local
McDonald’s. After all, social proof requires proof.
An intervention at Stanford University took a very different approach to 
reducing
a behavior
among undergraduate students. Researchers designed two different flyers to discourage binge
drinking. One took a rational approach, listing scary statistics about drinking like “One night of heavy
drinking can impair your ability to think abstractly for thirty days.” (Yes, this is a compelling
argument to many grade-chasing undergraduates worried about their performance on the next calculus
exam.) The other flyer linked drinking with the social lepers of university life: graduate students. This
flyer showed a graduate student drinking, along with the warning, “Lots of graduate students at
Stanford drink . . . and lots of them are sketchy. So think when you drink.... Nobody wants to be
mistaken for this guy.”
The two different flyers were posted separately in two different all-freshman dorms. Two weeks
after the flyers went up, residents were asked to complete an anonymous survey about how many
drinks they had consumed in the last week. Students in the dorm that was plastered with the sketchy
grad student flyers reported drinking 50 percent less alcohol than students in the dorm that received
the rational argument flyers. Were the students telling the truth? We can’t know for sure, as the
researchers didn’t follow them to any parties. It’s possible the undergrads didn’t want to be mistaken,
even in an anonymous research project, for a sketchy grad student. But if the reports were honest, this
study suggests a new strategy for discouraging unhealthy behavior: Just convince people it’s the habit
of a group they would never want to be a member of.
These two interventions demonstrate the importance of social proof for supporting behavior
change. We may be willing to give up our vices and cultivate new virtues if we believe that it
will more firmly secure us a spot in our most cherished tribe.

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