Influence: The Psychology of Persuasion

Cialdini organises compliance techniques into six principles: reciprocation, commitment and consistency, social proof, liking, authority and scarcity. He argues that each principle exists because it usually produces good decisions cheaply, and that compliance professionals exploit the shortcut by supplying the trigger without the substance behind it.

The research combines laboratory experiments with three years Cialdini spent in the field, training as a car salesman, a fundraiser and a telemarketer to observe what practitioners actually do. Each chapter pairs published studies with observed tactics. The reciprocation chapter covers the Hare Krishna flower gift and the rejection-then-retreat technique. The consistency chapter covers foot-in-the-door and the lowball tactic used in car sales. The social proof chapter covers pluralistic ignorance and bystander effects. The scarcity chapter covers limited-number and deadline tactics, and psychological reactance.

The book works in two directions. It gives sellers and fundraisers a set of tools, and it gives buyers a defence, since Cialdini explicitly tells readers how to detect and refuse each trigger. For operators the most useful material is on commitment devices, particularly the finding that commitments that are active, public, effortful and freely chosen change self-image and change later behaviour.

Some supporting studies have weakened since 1984. Certain social proof and priming results have replicated poorly, and the famous ones deserve checking before citation. The core principles have held up better than the individual experiments. A later edition adds unity as a seventh principle. The tactics chapters date the book in a useful way, because they show mid-century sales practice in detail that modern marketing books rarely provide.

Regents' professor emeritus of psychology and marketing at Arizona State University who studies compliance and influence.

Influence organises the persuasion research into six principles - reciprocity, commitment and consistency, social proof, authority, liking, scarcity - each tested experimentally and observed in the field among salespeople, fundraisers and negotiators. Pre-Suasion adds the timing question: what an audience attends to immediately before a request changes how they answer it.

Arizona State University