Final answer:
The bandwagon effect is a cognitive bias where people conform to the beliefs or actions of others due to the perception of popularity. It is commonly used in advertising and politics. Advertisers rely on the bandwagon effect to create the impression that everyone is buying their product.
Step-by-step explanation:
The bandwagon effect refers to the tendency for people to do or believe something simply because many others are doing or believing the same thing. It is a cognitive bias that can influence decision-making and lead to conformity. This phenomenon is often used in advertising and politics to create the impression that a product or candidate is popular and that everyone is supporting it. For example, advertisers might use slogans like 'Join the thousands who have already bought our product!' to encourage others to jump on the bandwagon.