Final answer:
Social proof is the tendency to believe or do something based on the actions or beliefs of others. Advertisers often use social proof to influence consumer behavior by creating the perception that everyone is buying a certain product.
Step-by-step explanation:
The tendency to do something or believe something because many other people do or believe the same thing is often referred to as social proof. Social proof is a psychological phenomenon where individuals look to others for guidance and make decisions based on the perceived consensus. Advertisers often use the bandwagon fallacy, which relies on social proof, to create the impression that everyone is buying a certain product, influencing others to do the same.