Bandwagon effect
Phenomenon whereby the rate of uptake of beliefs, ideas, fads and trends increases the more that they have already been adopted by others
The bandwagon effect is a psychological phenomenon where people adopt certain behaviors, styles, or attitudes simply because others are doing so. More specifically, it is a cognitive bias by which public opinion or behaviours can alter due to particular actions and beliefs rallying amongst the public. It is a psychological phenomenon whereby the rate of uptake of beliefs, ideas, fads and trends in... Wikipedia