Robert Cialdini
Influence, 1984Six principles govern how humans decide to trust a person, company, or recommendation — authority, social proof, liking, scarcity, reciprocity, and commitment. None of them are rational. All of them are predictable. Cialdini spent decades documenting that these triggers fire automatically, before conscious evaluation begins. The implication for any business competing for clients is significant: you are not being evaluated rationally. You are being scanned for trust signals that fire or don't fire within seconds.