Aggression and Violence Defined
Aggression is defined by psychologists as a range of behaviors that are intended to cause harm to others. While those behaviors often stem from anger, they can take root at a range of emotions such as jealousy, fear, or sadness, to name a few. Because the terms "aggression" and "violence" are used interchangeably in daily language, it is important to distinguish aggression from violence. Both aggression and violence can be physical, mental, or verbal. Violence, however, is an extreme expression of anger. Violence is defined as the enactment of aggression; it is an assault with intent to harm or injure others. Not all aggression leads to violence.
Types of Aggression
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, 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 factors that impact aggression, including biological factors (such as testosterone) and environmental factors (such as social learning). Empirical cross-cultural research has also found differences in the levels of aggression in different 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).
Some attribute the higher rates of physical aggression in the U.S. to the competitive instrumental aggression inherent in capitalism. The idea behind this thought is that capitalism is a system driven by private owners for profit, and getting ahead in this kind of system sometimes requires aggressive tactics.
A person's beliefs about the social acceptability of aggression (called 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 vary from culture to culture, and may partially explain cultural differences in aggression towards certain groups.
Some people suggest that aggression can be learned through observation, such as in Albert Bandura's cornerstone experiment, where children imitated the aggressive behavior toward a Bobo doll that was initially displayed by an experimenter. However, these conclusions have come under recent scrutiny. While it is debatable whether aggression can be learned through social learning (Gauntlett, 1995), or whether violence in media leads to higher rates of aggression (Fanti et al., 2009), there is evidence that suggests that repeated exposure to violence may desensitize individuals to later violence (Sparks, Sparks, & Sparks, 2008).
Gender
In psychological research about gender, the general pattern is that women are more likely to internalize, and men are more likely to externalize. This pattern holds true for aggression and violence. Men are more physically aggressive than women, which explains, in part, why they are responsible for the vast majority of murders committed in the United States (Buss, 2005). This sex difference has been noted across ages and cultures. In contrast, women are more likely to be indirectly and non-physically aggressive, such as in displays of relational aggression and social rejection. Whether this sex 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.
Hostile aggression
Hostile aggression involves direct aggression with the intent of physical or emotional harm to another person. It differs from instrumental aggression, which uses aggression as a means to an end.