Influence: The Psychology of Persuasion
Robert Cialdini · 1984
"People say yes for six predictable, exploitable reasons — reciprocity, commitment, social proof, liking, authority, and scarcity — and knowing the levers is the best defense against having them pulled on you."
Cialdini spent years undercover training as a used-car salesman, fundraiser, and telemarketer to catalog the tricks that actually work. In 1984 he distilled them into six weapons of influence that still explain most modern persuasion, from ads to cults.
Reciprocity: an unsolicited free sample creates a felt obligation to return the favor, often disproportionately. Commitment and consistency: getting someone to make a small public commitment (even signing a petition) makes them far more likely to agree to a larger, related request later, because reversing course threatens their self-image. Social proof: people copy the behavior of others, especially under uncertainty, which is why fake laugh tracks and 'most popular' labels work. Liking: we say yes more to people who resemble us, compliment us, or cooperate with us. Authority: white coats, titles, and uniforms trigger compliance even when the authority is irrelevant to the request. Scarcity: 'limited time' and 'only 3 left' increase desire not because the item improved, but because losing access feels worse than never having had the option.
Why does getting someone to make a small, voluntary commitment early make them more likely to agree to a bigger related request later?
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The explanation above is written with AI assistance. These are the originals — go to them to check it.
- Influence: The Psychology of PersuasionHarper Business
Pre-Suasion
"The most effective persuasion happens before the actual request — by directing someone's attention to the right idea in the moment right before you ask."