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The Science of Persuasion

The Science of Persuasion

When someone offers you a free sample, it’s not really free. It comes with the implied expectation that if you accept it, you will feel obligated to return the favor and eventually pay for the full product.

That’s just one of the many insights psychology has uncovered about the subtle mechanics of persuasion and how people can recognize and respond to attempts to influence their behavior.

“Persuasion is no longer just an art, it’s an out-and-out science,” said Dr. Robert Cialdini, professor emeritus of psychology and marketing at Arizona State University, speaking at the 125th annual convention of the American Psychological Association. “Indeed, a vast body of scientific evidence now exists on how, when, and why people say yes to influence attempts.”

Through his decades of research on social influence, Cialdini has formulated six universal principles of influence.

The first is reciprocity. This is a simple quid-pro-quo relationship where people feel the need to return a favor, he explained. Everyone has encountered this with the “free sample” marketing campaigns or the “free trial.”

This leads to the next principle, commitment, according to Cialdini.

Once someone is hooked on a product, it’s easier to get him or her to commit to paying for it.

When people decide or promise, they tend to stick to their word, according to this principle. If that commitment ends up being out of line with their internal beliefs, people tend to rationalize or change their beliefs to be in alignment with that choice, he added.

This is also the basis of the low-ball approach favored by car salespeople, according to Cialdini, who conducted research early in his career suggesting that a preliminary decision to take an action tends to persist even after the costs of performing that action have been increased.

Humans also have an innate pack mentality, which Cialdini calls social proof, citing research he conducted with hotel guests who were asked to reuse towels to save the environment. His study found that guests were 29 percent more likely to reuse their towels if they were told that most other guests chose to reuse the towels. The percentage went up to 39 percent when they heard the majority of guests who had stayed in that room reused their towels.

Authority is another powerful principle in play in almost all efforts at persuasion, he noted. If someone is an expert in a field, people often believe he or she is more likely to be effectively persuasive, according to Cialdini.

“When it comes to world economics, who are you more likely to listen to for advice: A Nobel laureate in the field or some random commenter on Facebook?” he asked.

People are also more likely to listen to others who are complimentary and similar to them. This is known as the principle of liking, according to Cialdini.

Finally, people are more likely to want what they think they can’t have. This is the principle of scarcity, which works through the concept of anticipated regret, where people look to the future and regret the possibility that the option of a decision might be taken away from them, he explained. One example of this is when stores offer a sale with limited availability.

These principles are so powerful, they generate desirable change in the widest range of circumstances, he said.

But influencing others is not the same as manipulating, he noted. To ensure that changing other’s behavior is effective and long-lasting, it is imperative to use the principles ethically, he said.

For example, he cited numerous studies that showed companies using dishonest hiring practices are more likely to have stressed employees, which leads to higher absenteeism, higher medical bills, and higher turnover.

“People, companies, and marketers need to ask themselves whether the principle of influence is inherent in the situation — that is, do they have to manufacture it or can they simply uncover it? That is important. No one wants to be a smuggler of influence,” he said. “Claiming to be an expert when they’re not, exploiting power, those eventually will have negative consequences.”

People can also develop resilience to manipulation by others, he said.

By taking time to become familiar with and understand when these principles are being used, individuals can spot the influence attempt. Does the person trying to influence really have authority? When someone says something is rare or scarce, is he telling the truth?

“We can focus too heavily on economic factors when seeking to motivate others toward our offerings and ideas,” he said. “We would do well, as well, to consider employing psychological motivators, such as those we have covered here.”

Source: American Psychological Association

The Science of Persuasion

Janice Wood

Janice Wood is a long-time writer and editor who began working at a daily newspaper before graduating from college. She has worked at a variety of newspapers, magazines and websites, covering everything from aviation to finance to healthcare.

APA Reference
Wood, J. (2018). The Science of Persuasion. Psych Central. Retrieved on October 1, 2020, from
Scientifically Reviewed
Last updated: 8 Aug 2018 (Originally: 6 Aug 2017)
Last reviewed: By a member of our scientific advisory board on 8 Aug 2018
Published on Psych All rights reserved.