Reasonable Doubt

A Guide to Changing Someone Else’s Beliefs

Use the science of persuasion to your advantage

Kate Morgan
Published in
6 min readFeb 25, 2019


Illustration: Keith Rankin

CChanging minds is hard to do: When our most dearly held opinions — things like political convictions, religious beliefs, morals, and core principles — are challenged, our brains put up one hell of a fight to protect them. Research has shown that when deeply held beliefs are called into question, the amygdala, a part of the brain that processes emotions, kicks into high gear as if we were encountering danger, leaving us in no mood to consider a difference of opinion.

And yet people convincing other people to believe things is what makes the world go around. Whether you’re selling a product, angling for a promotion, or running for office, the odds are good that your job requires you to influence and persuade people in some capacity. And outside of work, many of our social relationships are built on shared beliefs: We often get along best with people who agree with us.

The same science that helps us understand how beliefs are formed can actually help us get better at changing them. The first thing you need to understand about persuasion, explains Robert Cialdini, author of Influence: The Psychology of Persuasion, is that what you’re saying matters far less than who you are.

“Most of us think that the message and the merits of the message are the things that will convince people,” Cialdini says. “That’s usually not the case. Very often, it’s the relationship we have to the messenger. It’s not always about the argument, but about the delivery.”

This may seem like a no-brainer, but it’s much easier to influence people who are already close to you. This is in part because their brains are already primed for the right chemical reaction. Neuroscientist Paul Zak has spent most of his career researching oxytocin, a neurotransmitter associated with love, happiness, bonding, and — as Zak’s research has demonstrated — trust.

“It makes you more sensitive to social information,” he says. “I can more effectively persuade you if I flood your brain with oxytocin.” If you’re trying to convince a friend, family member, or partner of something, your odds are better if you soften them up with reminders of your…



Kate Morgan
Writer for

Kate is a freelance journalist who’s been published by Popular Science, The New York Times, USA Today, and many more. Read more at