Robert Cialdini spent years undercover in sales rooms, fundraising offices, and used-car lots to answer one question: what actually makes a person say yes? He came back with seven principles. Not tricks. Patterns of human behavior so reliable that ignoring them in your copy is leaving money on the table.
Here they are, each with the one move that puts it to work in writing.
1. Reciprocity. People feel an obligation to give back. Give first: a genuinely useful guide, a free audit, a real insight in the email itself. The free thing has to have value, not just be bait, or the obligation never forms. In copy: lead with help, ask second.
2. Commitment and consistency. Once someone takes a small step, they act to stay consistent with it. Get a tiny yes early: a low-friction question, a one-click reply, a checkbox. In copy: ask for the small commitment before the big one, and remind them of the choices they already made.
3. Social proof. When unsure, people copy people like them. Not generic “thousands of happy customers,” but specific proof from someone the reader recognizes as themselves. In copy: use the testimonial from the customer who shares the reader’s exact situation, with a name and a result.
4. Authority. We defer to credible experts. Show the credential, the data, the years, the named source. In copy: cite the real number, the real study, the real track record. Borrowed authority (a known name, a recognizable logo) works too.
5. Liking. We say yes to people we like, and we like people who are similar, who pay us compliments, and who are on our side. In copy: write like the reader talks, take their side against a shared enemy (the bloated agency, the confusing tool), and be human, not corporate.
6. Scarcity. We want what we might lose. Real deadlines, real limits, real consequences of waiting. In copy: state the genuine limit (“the demo is live for 7 days, then we take it down”) and never fake it. A fake countdown that resets kills trust the moment it is noticed.
7. Unity. The newest principle, and the strongest. It is not just similarity, it is shared identity: “one of us.” Family, team, profession, place. In copy: speak to the reader as a member of the group they belong to (“as a small-business owner, you already know…”), not as a target.
The honest part
Cialdini calls these “weapons of influence,” and weapons can be misused. The same scarcity that helps a real deadline land also powers the fake countdown timer. The difference is not the technique. It is whether the claim is true.
KK’s position is simple: use all seven, never lie with any of them. Reciprocity with a worthless freebie, social proof with invented reviews, scarcity with a fake deadline. Each one works once, then poisons the relationship and the brand. Persuasion built on true claims compounds. Manipulation built on false ones collapses.
How to use this tomorrow
Take one page of copy and score it against the seven. Most pages use one or two by accident. Add two more on purpose:
- Is there real social proof from someone like the reader? If not, add it.
- Is there a true scarcity or a clear reason to act now? If not, find the honest one.
- Are you speaking to the reader as “one of us”? If not, rewrite the opening line to do it.
Takeaway: You do not need all seven in every piece. You need at least one done well, true, and aimed at the reader’s actual situation.