How to Make You Say “Yes”

More than half a century ago, during World War II, psychologists became seriously interested in the question: how can you make a person say “yes”? Back then, the goal was to use propaganda among enemy troops and civilians as part of psychological warfare. Since then, countless sociologists and psychologists have studied the ways one person can influence the views and actions of another. But today, in our relatively peaceful times, the main goal of such research is different: to get you to buy a particular product. To do this, six methods—six motivating factors inherent to human nature—are used. These are discussed in an article by Robert Cialdini, a psychologist at the University of Arizona (USA).

1. Reciprocity

In almost every culture, the feeling of gratitude is considered one of the most important. It’s believed that this feeling became ingrained in human behavior through natural selection—families and primitive communities whose members had this trait were stronger and more successful. That’s why, when we receive a gift, even a small or unnecessary one, we feel compelled to give something in return.

For example, an American charity sent letters to private addresses asking for donations, using addresses from the phone book. Eighteen percent of recipients responded. When the same letters included a small gift—a pocket calendar—35 percent responded with donations.

This technique is used not only by charities. Companies that make cosmetics, cigarettes, office supplies, and various foods often organize free giveaways or product tastings in stores or even on the street. Afterward, many customers feel obligated to buy the product.

Pharmaceutical companies spend millions of dollars annually to support medical research and tens of thousands on small gifts for individual doctors—pens, calendars, bags with the company logo, and so on. The expense is small, but the gift can influence both research results and the medications doctors prescribe to their patients. In 1998, the New England Journal of Medicine analyzed studies and found that among researchers who received some material support from a drug manufacturer, only 37 percent made critical remarks about the new heart medication they were testing. On the other hand, 100 percent of those who found no flaws in the new drug either received research grants from the company, worked in one of its departments, or had their business trips paid for by the company.

A gift that triggers gratitude doesn’t have to be material—it can be a service or even a concession. The article’s author conducted an experiment: random passersby were stopped on the street and asked to help a teacher take a group of schoolchildren to the zoo. Only 17 percent agreed. Then, psychologists started with a much bolder request: they asked if the person would volunteer at a school, supervising children for two years, two hours a week. Everyone refused. Then the experimenter asked, “Well, could you at least take a group of schoolchildren to the zoo right now?” This time, 50 percent agreed.

2. Commitment and Consistency

The owner of a famous restaurant in Chicago was frustrated by unreliable customers: many would reserve a table and then not show up. By changing just two words and the tone in the phrase used by the reservation clerk, the owner reduced no-shows from 30 percent to just 10 percent. Previously, the clerk would say, “Please call us if your plans change.” Now she asked, “Could you call us if your plans change?” She would pause, and the customer would naturally reply, “Yes, I’ll call.” This way, the customer made a more concrete commitment.

Another example: in Israel, a charity campaign for people with disabilities was conducted. On psychologists’ advice, two weeks before the donation drive, people went door-to-door asking residents to sign a petition in support of people with disabilities. When the donation collectors returned two weeks later, the amount collected nearly doubled compared to areas where there was no such psychological preparation. Those who signed the petition felt uncomfortable not helping with a donation as well.

3. Social Proof

On a winter morning in 1969, a man stood at a busy intersection in downtown New York and stared at the sky for 60 seconds. This was part of an experiment by psychologists at the City University of New York to see how passersby would react. Most people just walked around him, some nudged him, and only 4 percent stopped to look up as well.

Then the experiment changed: instead of one, five “plants” stood at the intersection. Now, 18 percent of passersby followed their example. When the number of “plants” increased to 15, 40 percent of passersby stopped, causing a real traffic jam at the intersection. The psychologists then apologized to the crowd, who dispersed with embarrassed smiles.

Another study showed that if door-to-door fundraisers show a list of neighbors who have already donated, the “harvest” increases sharply.

The effect of social proof is widely used in advertising: TV commercials often show crowds storming a store to buy the advertised product, or friends fighting over a pack of gum.

Less well-known are cases where social proof works in the opposite direction, to the surprise of advertisers. For example, anti-smoking, anti-alcohol, and anti-drug campaigns often emphasize how widespread these problems are. Social ads show teenagers smoking or using drugs, or display graphs of rising alcohol consumption. While these messages are well-intentioned, sociological studies have shown that such campaigns can actually increase the spread of undesirable behaviors.

4. Liking

People are more likely to say “yes” to someone they like. Some companies don’t sell their products in stores or advertise in print or on TV, but instead use networks of friends and acquaintances. Examples include Herbalife and Zepter cookware. The American company Tupperware sells its plastic food containers through specially hired agents—housewives. A housewife invites her friends over to her home to show them the wonderful, affordable, practical, and beautiful containers, which nest inside each other like Russian dolls and take up no space. And her friends buy the products. This method works because you’re more likely to say “yes” to a friend than to a stranger. It’s estimated that every 2.7 seconds, a Tupperware party starts somewhere in the world, and 75 percent of these home sales happen outside the U.S.—a country known for its individualism.

A study conducted about 30 years ago in Canada showed that in local government elections, attractive, photogenic candidates won more often. When asked if a candidate’s appearance mattered, voters insisted they only cared about the candidate’s platform and experience.

This is why advertising so often features models and famous actors who are widely liked.

5. Authority

It’s generally hard to get Americans to cross the street on a red light. But the number of people who followed a “leader” across the street increased by 350 percent if the experimenter was dressed in a formal business suit—black or dark, with a tie and gold cufflinks. These signs of authority and high social status made many pedestrians follow the well-dressed person, even if he was clearly breaking the law. This experiment was conducted in Texas in 1955.

In other countries, people may cross the street without paying much attention to traffic lights or others’ clothing. A more relevant example: in toothpaste ads, an actor in a white lab coat claims the toothpaste is “recommended by all dentists.” It’s a clever, if not entirely honest, advertising trick.

6. Scarcity

While working at the University of Florida, psychologist Stephen West noticed that one day, students started giving much better reviews to the food at a campus cafeteria. The day before, they had preferred other dining options. It turned out the cafeteria had been closed for several weeks due to a fire and repairs. After reopening, the food “tasted better.” This case proves that we value things more when they’re unavailable.

That’s why advertisers are right to include phrases like “offer valid for one week only” or “limited stock available.” If a product uses rare or hard-to-find natural ingredients—like shark fins, Tibetan plants, or cosmic dust—it’s always mentioned in the ad, whether it’s true or not.

A student who was writing his thesis under the article’s author also ran a beef import business in the U.S. As an experiment, he asked his staff to tell supermarkets that, due to a drought in Australia, beef imports from that continent would soon decrease (which was true). As a result, beef purchases more than doubled compared to stores that weren’t told this. Then, when calling a third group of stores, the managers added that this was confidential information from an employee of the Australian national weather service. These stores bought 600 percent more beef than those who were simply offered Australian meat.

Cultural Differences in Influence

The importance of these six factors varies across cultures. Employees of a large international bank were asked to help a colleague with a work task. Americans, when deciding whether to help, asked themselves, “Do I owe this colleague anything? Has he helped me before?” (reciprocity). For Chinese employees, it was important whether the person asking for help was a boss or had connections with management (authority). Spaniards based their decision mainly on how much they liked the colleague. For Germans, the most important thing was duty: if they could be convinced that helping was part of their job description, they would help.

Conclusion: Can We Resist Manipulation?

So, advertising agencies use six features of human perception and behavior to make us say “yes.” All these psychological traits are generally useful—otherwise, they wouldn’t have survived natural selection. And there’s nothing immoral about using them in advertising, as long as the product being promoted is genuinely good.

Are we doomed to be manipulated by those who know and use these principles? No. Now that you’re familiar with the basics of advertising persuasion, you can spot these six techniques in ads or propaganda and make decisions based on reason, not emotion.