Here's a ‘really simple’ way to change people’s minds, says Wharton persuasion expert: It makes people 30% likelier to say yes

Asking someone for help can feel like a burdensome request. Asking for a helper tells the other person that you respect their expertise, flattering them into agreement.

That's just one example of turning "options into identities," says Jonah Berger, a marketing professor at the Wharton School of the University of Pennsylvania. It's a "really simple" trick with a big impact, he adds: Requesting helpers instead of help, for example, can make people up to 30% more likely to act.

People often feel too busy to do what they're "supposed to" do, whether that's going to the gym or voting each November — unless it gives them a chance to showcase a positive part of their identity.

"Framing actions as opportunities to claim desired identities will make people more likely to do them," Berger tells CNBC Make It. "If voting becomes an opportunity to show myself and others that I am voter, I'm more likely to do it."

The strategy can motivate people to enact positive behaviors and avoid negative ones, Berger says. Coaches, teachers and parents often use this tactic to motivate groups.

"Cheating is bad, but being a cheater is worse. Losing is bad, being a loser is worse," says Berger.

How to use this strategy in your day-to-day life

Being persuasive often comes down to "subtle shifts in our language," Berger says. The individual words you use are often more important than actual nature of your message, argument or request, he notes.

"We think individual words don't really matter that much. That's a mistake," says Berger. "You could have excellent ideas, but excellent ideas aren't necessarily going to get people to listen to you."

At work, if you want someone to write up a pitch to send to a client, you can ask, "Do we have any writers in the office?" If you're looking to learn a new skill, find out if anyone considers themselves a teacher.

You can also turn the strategy inward and attempt to change your own mind. Saying you run implies you occasionally do it. Saying you're a runner sounds more assertive, and if you don't already regularly jog, you might enable a new habit.

"I'm a runner. I'm a straight-A student. We tell little kids, 'You don't just read, you're a reader,'" Berger says. "You do these things because that's the identity you hold,"

One more persuasive language trick

Berger's book "Magic Words," which published last year, explores other simple language tricks that can make you more convincing to your friends, coworkers and boss.

One such quick fix: People are more likely to follow your recommendations and ideas if you speak and write in the present tense.

Last year, Berger co-authored an analysis of more than 200,000 book and music reviews. "The more sentences in that review that used present tense, the more useful people found it," he recently told the "Knowledge at Wharton" podcast.

The present tense is more persuasive for two reasons, Berger said: It generalizes your experience and makes you sound more confident.

"If you're willing to say not just that France was fun, but it is fun; not just that this book had a great plot, but it has a great plot; when you're generalizing beyond the past, it suggests you're more confident or certain about what you're saying," Berger said. "As a result, people are more likely to follow up on your opinion and be persuaded."

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