as a robbery or as part of gang conflict in which multiple individuals are shot. Minimum number of victims In the United States in particular, lone actor attacks are associated with mass shootings in which multiple people are shot – although the definition of a mass shooting is also contested. Different sources describe the minimum number of victims as between three and five, with most authorities describing four as the minimum. Some sources include injured victims in the total while other definitions specify the victims must be dead in order to be counted. Motives Academic studies tend to distinguish between grievance driven lone actors and lone actor terrorists. Ideological (terrorist) Lone actor terrorists are ideologically driven, with political or religious motives, and are intended to create fear and influence public opinion. Lone wolf terrorists may sympathize with and consider themselves part of larger groups, but they are usually not active participants. The links between lone wolves and actual terrorist groups tend to be informal and conducted online. These individuals tend to become radicalized online and through media outlets. There have been cases of terrorist attacks conducted by individuals which were later found to have been directed remotely by terrorist organisations. Thus they were technically not lone wolves. Non-ideological (grievance driven) Most lone actor shootings are committed by individuals with a grievance against an institution, such as their former school or workplace, with no ideological motivation. In the United States, the perpetrators generally use guns, whereas in other countries where the public have less access to guns (such as China), knives may be used to commit mass stabbings. History Historian Richard Jenson says the years 1878–1934 were the era of anarchist terrorism and should be considered the classic age of ‘‘lone wolf’’ or leaderless terrorism. Anarchists rejected authoritarian, centralized control over acts of planned violence as well as over anything else. Jenson says there were hundreds of violent anarchist incidents during this period most of which were committed by lone individuals or very small groups without command structures or leaders. Since 1940, there have been around 100 successful lone wolf attacks in the United States. The number of attacks is increasing, however, and has grown each year since 2000. As compared to those on the far right, lone wolf attackers who become inspired by al-Qaeda and ISIS tend to be younger and better educated. According to studies, lone wolves have more