They are as follows:
1. Theory of irrationality:
According to this theory, people indulging in collective violence understand and foresee the consequences of their actions when they act in large groups and crowds. Freud has supported this theory. The agitation by the Gujar community in Rajasthan in 2008 against the Government and insurgency prevailing in North-East parts of India provide an illustration of this kind of collective violence. Terrorism and naxalite movement is also covered under this theory.
2. Theory of Frustration-Aggression:
It has generally been observed that uprisings and collective violence often errupts due to deprivation of people of their socio-economic and political rights. People in general are unhappy about the government in power and they resort to aggression out of frustration and deprivation. The latest illustration is uprising by Egyptian people against the Hosni Mubark’s autocratic rule. Other examples are American Civil War, 1865; Russian Revolution 1917, Pak- Bangladesh War, 1971 etc.
3. Theory of Social Concern:
This theory is propounded by William Kornhauser who explained that cult-membership of people prompts them to join a group in order to have a sense of belonging. This often leads to hatred against other groups of society resulting into riots, agitations and group-clashes which are different forms of violence. The violence errupted as a result of Mandal Commission’s report in 1994, Malegaon Blast of Sept. 8, 2006 killing 36 persons and injuring more than 100 persons and communal riots which are illustrations on the point.
4. Theory of structural strain:
Many a times people join together and resort to collective violence due to some generalised belief what they consider to be a norm. They mobilise into action in the form of collective violence. The recent uprisings in the Middle East countries to replace the monarchies by democratic government may be cited as an illustration. However, some writers have criticised this theory as being confusing as this phenomenon is better explained by Frustration- Aggression theory.
5. Resource Mobilisation Theory:
According to this theory, collective violence requires resource mobilisation by the group of persons indulging in this action. Time, money and communication resources are pre-requisites for a collective violent action. Terrorism, naxalite movement provide the best examples to show as to how these resources are being exploited and misused by these violent groups. Terrorists attack on US World Trade Centre on September 11, 2001 and on Indian Parliament on December 13, 2001 amply demonstrate how this theory applies to vigilante terrorism.