Bandwagon effect

The tendency to adopt a belief, behavior, or preference because many other people appear to hold it. Perceived popularity can influence choices even when people lack independent evidence.

Informational social influence: Influence that leads people to use others’ behavior as evidence about reality. A crowd can look like evidence that a belief or choice is correct.
Asch conformity experiments: Experiments in which participants sometimes gave an obviously incorrect answer to match a unanimous group. They demonstrate public conformity under group pressure, a related but not identical process.
Social influence marketing: Marketing that uses social relationships or popularity cues to affect consumer behavior. Sales claims and visible endorsements can make adoption itself seem like evidence of value.
Information cascade: A process in which people disregard private information and follow earlier choices made by others. A cascade can make early choices snowball into widespread adoption, even when they are mistaken.
Social influence in social networks: The study of how people’s attitudes and behavior affect one another through social connections. Network structure helps determine whether apparent popularity reflects independent choices or repeated influence.
Normative social influence: Influence that leads people to conform to gain approval or avoid social disapproval. Some people follow a popular choice to fit in, not because they believe it is right.
Groupthink: A decision-making failure in which a cohesive group suppresses dissent and critical evaluation. Groupthink concerns flawed collective deliberation, not simply adopting what seems popular.
Network effect: An increase in a product’s value to each user as more people use it. Unlike mere popularity, a network effect can make widespread adoption materially useful.
Preference cascade: A rapid shift in public expression as people reveal preferences after perceiving that others have done so. Visible conformity can abruptly expose or reshape what seems to be the majority view.
Algorithmic amplification: The increased visibility of content caused by computational ranking or recommendation systems. Platforms can make a behavior appear more popular than its underlying prevalence warrants.

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Argument from authorityCompared with: Popularity is not expertise, though both can be mistaken for evidence.