Unity principle
We say yes to those we feel are truly one of us.
What it means
Cialdini's seventh principle of influence: people are more readily persuaded by others with whom they share a salient sense of identity — a 'we,' grounded in kinship, place, or shared category, rather than mere similarity or liking. Unity is about co-belonging ('being of the same') so strongly that the other's interests feel partly like one's own, which dissolves the usual buyer-seller wariness. It differs from liking, which rests on attraction; unity rests on shared identity and shared action. It matters because invoking a common identity ('as fellow alumni') can be among the most potent compliance levers.
Examples
A fundraising letter that opens 'As a fellow parent at this school...' outperforms a neutral appeal.
A builder who mentions he grew up on the same estate wins the job over a cheaper stranger. The customer hasn't merely warmed to him; he registers as one of us.
A union organiser who has worked the same production line for a decade signs up members that a polished outside consultant never could — identical arguments, but a genuinely shared 'we'.
First described in Robert Cialdini, 'Pre-Suasion' (2016).