The primary meaning of the term violence refers to the use of swift, extreme physical force resulting in injury and violation to persons or property. It also has a broader meaning extending to covert, psychological and institutional violence. Given this wider interpretation, different forms of discrimination, economic exploitation, ethnic and religious persecution can all be considered as examples of violence.
Violence can be classified into three categories: personal, collective or institutional. Personal violence is performed at the micro level, which means that violent acts are performed by individuals and directed at objects, animals or people. This category can also include self-harm. Some of the forms of this kind of violence are permissible and are not penalized by laws. More serious forms of violence such as aggravated assault, rape and homicide are normally criminalized. To comprehend the causes for individual violence, criminologists and psychologists have studied personality types, family history and possible physiological deviations.
Collective violence occurs when groups of individuals engage in violent actions including riots, revolutions and gang warfare. Psychologists argue that this type of violence can lead to more serious consequences than personal violence. Members of such groups experience "deindividualization" and can lose feeling of their personal responsibility of what they are doing and are more likely to commit greater violent acts.
Institutional violence covers violent deeds that serve institutional purposes. It includes extreme phenomena like wars, killing and torture at concentration camps or murders committed by totalitarian governments. The violent acts which were committed during the Crusades (1095-1272) can also be classified as forms of institutional violence. A specific form of violence is terrorism, as it combines the features of all three types of violence mentioned previously.
Violence can also be classified into different types, according to its locus, or where it takes place. Examples of this kind of violence include in the home and workplace. Domestic violence is characterized as harassing or aggressive behavior within an intimate relationship. This form of violence is among the most under-reported of crimes. Domestic violence typically involves physical and sexual attacks, psychological abuse, in addition to harming property or pets. It can result in serious physical and psychological trauma. Women subjected to domestic violence are known to have developed battered women's syndrome (BWS), which is a form of a post-traumatic stress disorder (PTSD). Studies have shown that children exposed to domestic violence are more likely to suffer from emotional and psychological problems. Moreover, children exposed to violence perform worse at school and as a result have poor academic achievements.
Workplace violence is a phenomenon that has escalated. It involves acts of aggression, physical attacks, or threatening behavior that happens at a workplace and leads to physical or emotional harm to colleagues or customers. A wider definition of this type of violence includes forms of sabotage on workplace property. The majority of workplace violence does not come from workers or managers. It is carried out by "non-employees" - people who are often dissatisfied customers, robbers or angry spouses. Bullying is a form of violence often associated with the workplace, although this has also been reported in schools, community organizations and neighborhoods. The rationales behind violent behavior have attracted significant attention from criminologists and psychologists. In the case of workplace violence, it can be provoked by an issue such as critical appraisals or lay-offs.
The nature of the factors that compel people to behave violently has been studied in detail by psychologists, with the Stanford prison experiment (1971) shedding light on this problem. The experiment, run by American psychologist Philip George Zimbardo (b.1933), involved a simulation of a prison, assigning to two groups of students the roles of prison guards and prisoners. The experiment, which had been planned to run for two weeks, lasted only six days. It was ended prematurely because the guards acted violently towards prisoners, who suffered great distress. Zimbardo attributed the violent behavior of the college students to the impact of the institutional situation.
The problem of justifying violence has attracted substantial attention from philosophers, especially during the 20th century. In her work On Violence (1970) Hannah Arendt (1906-1975) reviewed a raft of theories on this subject. However, Arendt concluded that violence could be justified only as means of defense against imminent dangers.