Why you say yes, even when you don't want to

The low-ball technique is solid science. Once you're hooked, you're more likely to pay up, research shows.

Story highlights

  • Six "principles of persuasion" make us more likely to say yes, expert says
  • They can be used against you, but you can also use them to your advantage

(CNN)A few years ago, Robert Cialdini found himself at a large appliance store, standing in front of a big-screen TV that he didn't particularly want and certainly didn't need. That said, it was a great deal on a model that had received high marks from a consumer group.

He recalls the salesman coming up to him and saying, "I can see you're interested in this model, at this price, and I can tell why. It's a great deal, but I have to tell you, that's our last one. And we just got a call from a woman who said she might be coming down to the store today to buy it."
    Minutes later, Cialdini -- the man who literally wrote the book on the power of persuasion -- was wheeling out of the store with a new TV in his shopping cart, wondering whether he'd been duped.
    Scarcity is one of Cialdini's six "universal principles of influence." Along with the other five -- reciprocity, commitment, social proof, authority and liking -- a good salesperson can talk someone into buying just about anything.
    Robert Cialdini
    Cialdini, who has been studying the science of social influence for decades, presented new findings on his six principles Friday at the American Psychological Association's annual convention in Washington.
    "We've always thought of successful persuasion as an art -- something that people are born with, a natural gift of saying just the right thing at just the right time," said Cialdini, professor emeritus of psychology and marketing at Arizona State University. "That's true, but what we haven't recognized traditionally is that it's also a science. It's something that can be taught and learned."
    That, of course, is a double-edged sword. It means you could end up being talked into buying something you otherwise wouldn't. But it also means you can harness these principles to your own advantage, to get what you want.

    Reciprocity

    What it is: "There is a rule in all human cultures that says you must not take without giving in return," Cialdini said, and this principle assures we do just that.
    How it's used: Myriad studies have shown that receiving a free sample at the supermarket or food court makes us significantly more likely to purchase something from the store handing it out, though not necessarily the exact product we've tasted. This principle also comes into play with the tote bags, T-shirts and sheets of return address labels you get in the mail.
    One caveat is that usefulness does matter, according to Cialdini. If what you're offered is cheap, unwanted or wasteful, you won't think of what you're receiving as a gift but rather as a trick -- and the tactic backfires.
    How you can use it: Want to get better presents from your family? Buy them something thoughtful first, and they'll be more likely to reciprocate. Want someone to do you a favor? Start by lending them an unsolicited helping hand before you make your own request. Cialdini says the effect is amplified when what you give is meaningful, unexpected and personalized.

    Commitment

    What it is: People want to be consistent with what they've already said or done. "If someone tries to get you to take a small step in a particular direction -- so small that it seems trivial -- beware, because you'll now be much more likely to take a larger step in that direction ... when asked," Cialdini said.
    How it's used: When you make a reservation at a restaurant, a simple change in the host or hostess' phraseology can make you much more likely to call back if your plans change, Cialdini says. Rather than telling you to "please call if you have to change or cancel your reservation," asking "will you please call if you have to change or cancel your reservation?" -- and waiting for an affirmative response -- results in far more compliance.
    How you can use it: As any good lawyer might tell you, always get your offer in writing. Bonus points if you're able to get someone to promise you something voluntarily or in front of witnesses. And if you have more than one request, Cialdini says, always start with the larger one. If you get rejected or denied, you can counter with a lesser ask, which is then more likely to be granted.

    Social proof

    What it is: "People want to follow the lead of what those around them, like them, have already done in a situation," Cialdini said. "That reduces our uncertainty about what we should do in that situation."
    How it's used: Think of it like peer pressure or pack mentality. Cialdini conducted a study with hotel guests who were asked to reuse their towels to help the environment. When they were informed that most other guests chose to reuse their towels, people were 29% more likely to do it themselves. When they were told that the majority of guests who stayed in their particular room reused their towels, people were 39% more likely to do it, too.
    How you can use it: This one's pretty simple. Want someone to do or buy something? Tell them -- or better yet, show them -- that others are doing it.

    Authority

    What it is: "People prefer to say yes to those who can show them evidence that what is being recommended comes from legitimate ... authorities on the topic," Cialdini said. "If an expert says it, it must be true," according to his presentation.
    How it's used: Look no further than the celebrity endorsement! These are particularly powerful if, for example, a professional athlete is pitching a product related to his or her sport. But, Cialdini says, if you simply dress someone up to look like an expert -- if you give them a suit and tie or eyeglasses -- that often works just as well.
    How you can use it: Don't ever assume that people know what your specialty is, Cialdini says. Remind them, and underscore why they should listen to you over everyone else. Do you have experience solving the type of problem now at hand? Lay it all out on the table.

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