Content Warning: This chapter contains references to the People’s Temple mass suicide.

Cialdini describes a restaurant in Beijing where, in an effort to boost the sales of certain dishes, they listed them as “most popular.” Sales of these dishes immediately increased. He writes, “Quite simply, the dishes became more popular because of their popularity” (128).

Cialdini attributes this success to a lever of influence called “social proof.” When advertisers say their product is the fastest selling or the most popular, they do not have to explain anything. Popularity speaks for itself. Unfortunately, there are profiteers who claim to have a product that is quite popular when it is not. Cialdini makes a list in the section “People Power” of various aspects of human behavior. In each, he reveals that the most prevalent behavior is led by a small group of initiators and followed by a large group of imitators. These behaviors include morality, criminality, problematic personal behavior, healthy eating, online purchases, bill paying, science-based recommendations, and environmental action. Not only individuals but also organizations tend to follow these leaders.

In “After the Deluge,” Cialdini expresses his favorite example of using social proof to create an unlikely growth in popularity.