Liking
The fourth of Robert Cialdini’s seven principles of influence. People say yes to people they like. The two cheapest, most reliable engines of liking are similarities and praise — both costless, both replicable, both repeatedly underestimated.
The two pillars
Per The PSYCHOLOGICAL TRICKS To Persuade & Influence ANYONE - Robert Cialdini & Lewis Howes (video):
1. Similarities
People like those who are like them.
- The negotiator email study: pairs of negotiators bargained over email. Half exchanged a small amount of personal information beforehand; half just got down to business. Stymied (deadlocked) negotiations dropped from 30% to 6%. When researchers looked closely, the predictor was not how much personal info was traded but whether the parties discovered parallel similarities — both runners, both only children, both from the same region. Generic small talk doesn’t move the dial; shared categories do.
- The implication: before a high-stakes interaction, do the homework — LinkedIn, Instagram, mutual connections — and find genuine commonalities to surface in the first sentence.
2. Praise
People like those who like them and say so.
Cialdini’s own confession: as a research-lab principal investigator, he would routinely think a compliment about a graduate student’s idea but not externalize it (“brilliant — that’s exactly what we should do”) — and lose all the social value that comes from the gap between mind and tongue. He says he had to train himself to say out loud anything he’d silently approve.
The praise must be warranted and specific. A phony compliment fails on inspection; the recipient hears it land hollow. The defense isn’t to give fewer compliments — it’s to do enough research that the praise is genuinely earned.
In practice: the cold-outreach script
A worked example from Lewis Howes’s early-career LinkedIn outreach (which he attributes to studying Cialdini):
- Three layers of similarity in the first sentence — mutual connections, shared school, shared sports, shared profession. (“I see we both know Bob, Sarah, and Tom, and we both played football.”)
- Specific, researched praise for something the recipient actually did. (“I was inspired by the way you handled X in your career.”)
- Don’t ask for advice first; ask for the story. People are tired of being asked for advice (it costs working time); they enjoy telling the story of how they overcame a challenge (it’s flattering and they have it ready). The advice falls out of the story for free.
Reply rates went from ~10–20% to ~80–90% on the same recipient population.
Why it stacks with the other principles
- The welcome letter at the top of a website — found to be the #4 strongest conversion factor in the 6,700-site A/B-test meta-study Cialdini cites — works because it deploys liking before anything else. (“Hello, glad you’re here, come on in.”)
- Liking is a force-multiplier on Reciprocation: a gift from someone you like obligates more than the same gift from a stranger.
- Liking is distinct from Unity, which Cialdini originally considered an extension of similarity but separated out in 2021. Liking-via-similarity is “we both do X.” Unity is “we both belong to the same X.” The we-pronoun does the heavy lifting in unity; mere parallel attributes do it in liking.
The downside no one talks about
Liking is the principle whose absence is hardest to notice. People rarely say “I disliked them, so I said no” — they invent post-hoc reasons for the no, and the seller never learns. Treat consistent unexplained no’s as a weak signal that the liking layer was thin.
Related
- Robert Cialdini — originator
- Unity — close cousin, formally separated out as the 7th principle in 2021
- Reciprocation — gifts deepen liking
- Ben Franklin effect — opposite causal direction (doing a favor creates liking)
- Authority — orthogonal but commonly stacked