What is "bandwagon effect"

n. (context sociology English) the observation that people often do or believe what they think many other people do.

n. the phenomenon of a popular trend attracting even greater popularity; "in periods of high merger activity there is a bandwagon effect with more and more firms seeking to engage in takeover activity"; "polls are accused of creating a bandwagon effect to benefit their candidate"

The bandwagon effect is a phenomenon whereby the rate of uptake of beliefs, ideas, fads and trends increases the more that they have already been adopted by others. In other words, the bandwagon effect is characterized by the probability of individual adoption increasing with respect to the proportion who have already done so. As more people come to believe in something, others also "hop on the bandwagon" regardless of the underlying evidence.

The tendency to follow the actions or beliefs of others can occur because individuals directly prefer to conform, or because individuals derive information from others. Both explanations have been used for evidence of conformity in psychological experiments. For example, social pressure has been used to explain Asch's conformity experiments, and information has been used to explain Sherif's autokinetic experiment.

According to this concept, the increasing popularity of a product or phenomenon encourages more people to "get on the bandwagon", too. The bandwagon effect explains why there are fashion trends.

When individuals make rational choices based on the information they receive from others, economists have proposed that information cascades can quickly form in which people decide to ignore their personal information signals and follow the behavior of others. Cascades explain why behavior is fragile—people understand that they are based on very limited information. As a result, fads form easily but are also easily dislodged. Such informational effects have been used to explain political bandwagons.