Reciprocity, commitment, social proof, authority, liking, scarcity, unity. Seven levers that move people to say yes — used well, or badly.
About the book
Robert Cialdini's Influence is the foundational text on the psychology of persuasion, identifying seven principles that reliably get people to comply — from the pull of a free sample (reciprocity) to the power of a testimonial (social proof) to the panic of a countdown timer (scarcity). Decades of behavioral research later, it's still the reference point for why certain copy, page layouts, and sales tactics work, and it's explicit about where persuasion tips into manipulation. Applied to product and marketing, it's less a bag of tricks and more a diagnostic for why trust signals succeed or fail.
Best used for
—Designing a testimonial or social-proof section that actually builds trust
—Diagnosing why persuasive copy isn't converting despite a strong offer
—Crafting urgency or scarcity messaging without crossing into manipulation
“This book can't be summarized. It can only be very, very strongly recommended.”
— Sundeep, Goodreads
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