Aggression and Violence Defined
Aggression is defined by psychologists as behavior that is meant to hurt others (Myers, 2004). However, definitions of violence and related words are used interchangeably in the literature, leading to some confusion. Violence and aggression are both terms used to denote force used against someone or something. Aggression takes a variety of forms among human beings, and it can be physical, mental, or verbal. Violence, similarly, can be physical, mental, or verbal.
There are two broad categories of aggression. These include hostile aggression (also known as affective or retaliatory aggression) and instrumental aggression (also referred to as predatory or goal-oriented aggression). Hostile aggression is accompanied by strong emotions, particularly anger, and is associated with impulsive, unplanned, overt, or uncontrolled behavior. Harming the other person is the goal of this kind of aggression. Instrumental aggression, in contrast, is a means to an end. It is often referred to as "predatory" aggression and is associated with goal-oriented, planned, hidden, or controlled behavior. In instrumental aggression, harming the person is used to obtain some other goal, such as money.
Social and Cultural Factors
Research indicates that there are many causes of aggression, including biological factors (such as testosterone) and environmental factors (such as social learning). Empirical cross-cultural research has also found differences in the level of aggression between cultures. In one study, American men resorted to physical aggression more readily than Japanese or Spanish men, whereas Japanese men preferred direct verbal conflict more than their American and Spanish counterparts (Andreu et al. 1998). Within American culture, southerners were shown to become more emotionally aroused and to respond more aggressively than northerners when affronted (Bowdle et al. 1996). There is also a higher homicide rate among young, white southern men than among white northern men in the United States (Nisbett 1993). Some attribute the higher rates of physical aggression in the US to the competitive instrumental aggressiveness inherent in capitalism.
A person's beliefs about the social acceptability of aggression (termed "normative beliefs") are major predictors of their behavior. For example, people's beliefs about the acceptability of violence against Jewish people in Pakistan predicted whether they would join an extremist group. Normative beliefs may partially explain cultural differences in aggression towards certain groups. As these beliefs are readily changeable through intervention, targeting normative beliefs may be a way to decrease aggression in certain individuals. Likewise, aggression can be learned through social learning by watching and imitating the behavior of others. A considerable amount of evidence suggests that watching violence on television increases the likelihood of short-term aggression in children (Aronson, Wilson, & Akert, 2005). A long-term study of over 700 families found a significant association between the amount of time spent watching violent television as a teenager and the likelihood of committing acts of aggression later in life. The results did not change even after accounting for factors such as family income, parental education, and neighborhood violence (Aronson, Wilson, & Akert, 2005).
Males are historically believed to be generally more physically aggressive than females (Coie & Dodge 1997, Maccoby & Jacklin 1974), and men commit the vast majority of murders in the United States(Buss 2005). This is one of the most robust and reliable behavioral sex differences, and it has been found across many different age groups and cultures. There is evidence that males are quicker to feel aggression (Frey et al. 2003) and more likely than females to express their aggression physically (Bjorkqvist et al. 1994). When considering indirect forms of non-physical aggression, such as relational aggression and social rejection, some scientists argue that females can be quite aggressive, although female aggression is less often expressed physically (Archer, 2004; Card, Stucky, Sawalani, & Little, 2008). Although females are less likely to initiate physical violence, they can express aggression by using a variety of non-physical or indirect means. Exactly which method women use to express aggression is something that varies from culture to culture. Whether this gender difference in aggression is a result of nature (such as biology, genetics, or hormonal differences) or nurture (such as gender roles and socialization) continues to be debated.