Lynching is an extrajudicial punishment by an informal group. It is most often used to characterize informal public executions by a mob, often by hanging, in order to punish an alleged transgressor, or to intimidate a minority group. It is an extreme form of informal group social control such as charivari, skimmington, riding the rail, and tarring and feathering, but with a drift toward the public spectacle. Lynchings have been more frequent in times of social and economic tension, and have often been a means for a dominant group to suppress challengers. However, it has also resulted from long-held prejudices and practices of discrimination that have conditioned societies to accept this type of violence as normal practices of popular justice. Though racial oppression and the frontier mentality in the United States have given lynching its current familiar face, execution by mob justice is not exclusive to North America, but it is also found around the world as vigilantes act to punish people behaving outside of commonly acceptable boundaries. Indeed, instances of it can be found in societies long antedating European settlement of North America.