{This post is part of the Archive of Human Exploits}
In his seminal 1986 book, Influence: The Psychology of Persuasion, social psychologist Dr. Robert Cialdini introduced six universal Principles of Persuasion:
1. Reciprocity. "Simply put, people are obliged to give back to others the form of a behavior, gift, or service that they have received first," Cialdini writes. He goes on to describe a series of experiments that explored what effect a little gift (e.g. mint) given with the bill had on a server's tip. One mint increased tips by 3%. Two mints increased tips by 14%. "But perhaps most interesting of all is the fact that if the waiter provides one mint, starts to walk away from the table, but pauses, turns back and says, 'For you nice people, here’s an extra mint,' tips go through the roof," Cialdini reveals. In that scenario, tips increased by 23%.
2. Scarcity. "Simply put, people want more of those things they can have less of," Cialdini writes. His prime example: Sales of flights on the Concorde spiked the day after British Airways announced it was discontinuing its twice daily London-New York route because it wasn't making money.
3. Authority. "This is the idea that people follow the lead of credible, knowledgeable experts," Cialdini explains. He describes an experiment where receptionists at a real-estate firm played up an agent's credentials before connecting the call. They'd say things such as, "Speak to Peter, our head of sales. He has over 20 years’ experience selling properties.” The result: A 20% increase in appointments and 15% increase in signed contracts.
4. Consistency. "People like to be consistent with the things they have previously said or done," Cialdini explains. He adds: "Consistency is activated by looking for, and asking for, small initial commitments that can be made." This can take many forms. A small but fascinating one is the effect of asking patients to fill out their own appointment cards (rather than having the staff do it). That simple act of stimulating consistency reduced missed appointments at a health center by 18%.
5. Liking. "People prefer to say yes to those that they like," Cialdini writes. Then he goes further and explains the three factors that cause us to like someone. "We like people who are similar to us, we like people who pay us compliments, and we like people who cooperate with us towards mutual goals." Simply discussing one thing they had in common before a negotiation led participants to a deal 90% of the time in one experiment, up from 55% when participants got straight to business.
6. Consensus. "Especially when they are uncertain, people will look to the actions and behaviors of others to determine their own," Cialdini explains. This is also known as "social proof theory," which Influence helped popularize. It was demonstrated in an experiment involving hotel towels. The aim was to get people to reuse them for both cost and environmental reasons. The experimenters tried various approaches, including those familiar to anyone who has stayed in a hotel (e.g. appeals to be "green"). The most effective? The message that "75% percent of people who have stayed in this room have reused their towel.” This increased reuse by 33%.
In his follow-up to Influence more than 30 years later, Pre-Suasion: A Revolutionary Way to Influence and Persuade, Dr. Cialdini added a seventh principle:
7. Unity. “It’s about the categories that individuals use to define themselves and their groups, such as race, ethnicity, nationality, and family, as well as political and religious affiliations," Cialdni explains. "Simply put, we is the shared me.” That is, the more we feel a person is one of “us,” the more likely we are to be influenced by them -- and before any active influencing actually begins. Cialdini adds this principle isn't new, rather it was "hiding beneath the surface" of his research data all along.
What to learn more? I highly recommend both of Dr. Cialdini's books:
