10.1 Defining Aggression

Learning Objectives

  1. Define aggression and violence as social psychologists do.
  2. Differentiate emotional from instrumental aggression.

Aggression is a word that we use every day to characterize the behavior of others and perhaps even of ourselves. We say that people are aggressive if they yell at or hit each other, if they cut off other cars in traffic, or even when they smash their fists on the table in frustration. But other harmful acts, such as the injuries that sports players receive during a rough game or the killing of enemy soldiers in a war might not be viewed by everyone as aggression. Because aggression is so difficult to define, social psychologists (as well as many other people, including lawyers) judges and politicians, have spent a great deal of time trying to determine what should and should not be considered aggression. Doing so forces us to make use of the processes of causal attribution to help us determine the reasons for the behavior of others.

Social psychologists define aggression as behavior that is intended to harm another individual who does not wish to be harmed (Baron & Richardson, 1994). Because it involves the perception of intent, what looks like aggression from one point of view may not look that way from another, and the same harmful behavior may or may not be aggressive depending on its intent.

You can see that this definition rules out some behaviors that we might normally think are aggressive. For instance, a football linebacker who accidentally breaks the arm of another player or a driver who accidentally hits a pedestrian would not by our definition be displaying aggression because although harm was done, there was no intent to harm. A salesperson who attempts to make a sale through repeated phone calls is not aggressive because he is not intending any harm. (We should say this behavior is “assertive” rather than aggressive.) And not all intentional behaviors that hurt others are aggressive behaviors. A dentist might intentionally give a patient a painful injection of a painkiller, but the goal is to prevent further pain during the procedure.

Because our definition requires us to determine the intent of the perpetrator, there is going to be some interpretation of these intents and there may well be disagreement among the parties involved. The U.S. government perceives the development of a nuclear weapon by North Korea as aggressive because the government believes that the weapon is intended to harm others, but North Korea may see the program as promoting self-defense. Although the player whose arm is broken in a football game may attribute hostile intent, the other player may claim that the injury was not intended. Within the legal system, juries and judges are frequently asked to determine whether harm was done intentionally.

Social psychologists use the term violence to refer to aggression that has extreme physical harm, such as injury or death, as its goal. Thus violence is a subset of aggression. All violent acts are aggressive, but only acts that are intended to cause extreme physical damage, such as murder, assault, rape, and robbery, are violent. Slapping someone really hard across the face might be violent, but calling people names would only be aggressive.

The type or level of intent that underlies an aggressive behavior creates the distinction between two fundamental types of aggression, which are caused by very different psychological processes. Emotional or impulsive aggression refers to aggression that occurs with only a small amount of forethought or intent and that is determined primarily by impulsive emotions. Emotional aggression is the result of the extreme negative emotions we’re experiencing at the time that we aggress and is not really intended to create any positive outcomes. When Sarah yells at her boyfriend, this is probably emotional aggression—it is impulsive and carried out in the heat of the moment. Other examples are the jealous lover who strikes out in rage or the sports fans at my university who, after our basketball team won the national NCAA championship, lit fires and destroyed cars around the stadium.

Instrumental or cognitive aggression, on other hand, is aggression that is intentional and planned. Instrumental aggression is more cognitive than affective and may be completely cold and calculating. Instrumental aggression is aimed at hurting someone to gain something—attention, monetary reward, or political power, for instance. If the aggressor believes that there is an easier way to obtain the goal, the aggression would probably not occur. A bully who hits a child and steals her toys, a terrorist who kills civilians to gain political exposure, and a hired assassin are all good examples of instrumental aggression.

Sometimes it is hard to distinguish between instrumental and emotional aggression, and yet it is important to try to do so. Emotional aggression is usually treated as second-degree homicide in the U.S. legal system, to differentiate it from cognitive, instrumental aggression (first-degree homicide). However, it may well be the case that all aggression is at least in part instrumental because it serves some need for the perpetrator. Therefore, it is probably best to consider emotional and instrumental aggression not as distinct categories but rather as endpoints on a continuum (Bushman & Anderson, 2001).

Social psychologists agree that aggression can be verbal as well as physical. Therefore, slinging insults at a boyfriend is definitely, according to our definition, aggressive, just as hitting someone is. Physical aggression is aggression that involves harming others physically—for instance hitting, kicking, stabbing, or shooting them. Nonphysical aggression is aggression that does not involve physical harm. Nonphysical aggression includes verbal aggression (yelling, screaming, swearing, and name calling) and relational or social aggression, which is defined as intentionally harming another person’s social relationships, for instance by gossiping about another person, excluding others from our friendship, or giving others the “silent treatment” (Crick & Grotpeter, 1995). Nonverbal aggression also occurs in the form of sexual, racial, and homophobic jokes and epithets, which are designed to cause harm to individuals.

The list that follows this paragraph (adapted from Archer & Coyne, 2005) presents some examples of the types of nonphysical aggression that have been observed in children and adults. One reason that people may use nonphysical rather than physical aggression is that it is more subtle. When we use these techniques we may be able to better get away with it—we can be aggressive without appearing to others to be aggressing.

  • Gossiping
  • Spreading rumors
  • Criticizing other people behind their backs
  • Bullying
  • Leaving others out of a group or otherwise ostracizing them
  • Turning people against each other
  • Dismissing the opinions of others
  • “Stealing” a boyfriend or girlfriend
  • Threatening to break up with partner if the partner does not comply
  • Flirting with another person to make a partner jealous

Although the negative outcomes of physical aggression are perhaps more obvious, nonphysical aggression also has costs to the victim. Craig (1998) found that children who were victims of bullying showed more depression, loneliness, peer rejection, and anxiety in comparison to other children. In Great Britain, 20% of adolescents report being bullied by someone spreading hurtful rumors about them (Sharp, 1995). Girls who are victims of nonphysical aggression have been found to be more likely to engage in harmful behaviors such as smoking or considering suicide (Olafsen & Viemero, 2000). And Paquette and Underwood (1999) found that both boys and girls rated social aggression as making them feel more “sad” and “bad” than did physical aggression.

Recently, there has been an increase in school bullying through cyberbullying—aggression inflicted through the use of computers, cell phones, and other electronic devices (Hinduja & Patchin, 2009). Perhaps the most notable recent example was the suicide of 18-year-old Rutgers University student Tyler Clementi on September 22, 2010. Tyler’s last words before he died were shared through an update to his Facebook status:

“jumping off the gw bridge sorry”

Clementi’s suicide occurred after his roommate, Dharun Ravi, and Ravi’s friend Molly Wei secretly enabled a remote webcam in a room where Tyler and a male friend were sharing a sexual encounter and then broadcasted the streaming video footage across the Internet.

Cyberbullying can be directed at anyone, but lesbian, gay, bisexual, and transgendered (LGBT) students are most likely to be the targets (Potok, 2010). Blumenfeld and Cooper (2010) found that 54% of LGBT youth reported being cyberbullied within the past three months.

Hinduja and Patchin (2009) found that youth who report being victims of cyberbullying experience a variety of stresses from it, including psychological disorders, alcohol use, and in extreme cases, suicide. In addition to its emotional toll, cyberbullying also negatively affects students’ participation in, and success at, school.

Social Psychology in the Public Interest

Terrorism as Instrumental Aggression

There is perhaps no clearer example of the prevalence of violence in our everyday lives than the increase in terrorism that has been observed in the past decades. These terrorist attacks have occurred in many countries across the world, in both Eastern as well as Western cultures. Even affluent Western democracies such as Denmark, Italy, Spain, France, Canada, and the United States have experienced terrorism, which has killed thousands of people, primarily innocent civilians. Terrorists use tactics such as killing civilians to create publicity for their causes and to lead the governments of the countries that are attacked to overrespond to the threats (McCauley, 2004).

How can we understand the motives and goals of terrorists? Are they naturally evil people whose primary desire is hurt others? Or are they more motivated to gain something for themselves, their families, or their countries? What are the thoughts and feelings that terrorists experience that drive them to their extreme behaviors? And what person and situational variables cause terrorism?

Prior research has attempted to determine if there are particular personality characteristics that describe terrorists (Horgan, 2005). Perhaps terrorists are individuals with some kind of deep psychological disturbance. However, the research conducted on various terrorist organizations does not reveal anything distinctive about the psychological makeup of individual terrorists.

Empirical data has also found little evidence for some of the situational variables that might have been expected to be important. There is little evidence for a relation between poverty or lack of education and terrorism. Furthermore, terrorist groups seem to be quite different from each other in terms of their size, organizational structure, and sources of support.

Arie Kruglanski and Shira Fishman (2006) have argued that it is best to understand terrorism not from the point of view of either particular personality traits or particular situational causes but rather as a type of instrumental aggression—a means to an end. In their view, terrorism is simply a “tool,” a tactic of warfare that anyone from any nation, military group, or even a lone perpetrator could use.

Kruglanski and his colleagues argue that terrorists believe that they can gain something through their terrorist acts that they could not gain through other methods. The terrorist makes a cognitive, deliberate, and instrumental decision that his or her action will gain particular objectives. Furthermore, the goal of the terrorist is not to harm others but rather to gain something personally or for one’s religion, beliefs, or country. Even suicide terrorists believe that they are dying for personal gain—for instance, the promise of heavenly paradise, the opportunity to meet Allah and the prophet Muhammad, and rewards for members of one’s family (Berko & Erez, 2007). Thus, for the terrorist, willingness to die in an act of suicidal terrorism may be motivated not so much by the desire to harm others but rather by self-concern—the desire to live forever.

One recent example of the use of terrorism to promote one’s beliefs can be seen in the actions of Anders Behring Breivik, 32, who killed over 90 people in July 2011 through a bomb attack in downtown Olso, Norway, and a shooting spree at a children’s campground. Breivik planned his attacks for years, believing that his actions would help spread his conservative beliefs about immigration and alert the Norwegian government to the threats posed by multiculturalism (and particularly the inclusion of Muslims in Norwegian society). This violent act of instrumental aggression is typical of terrorists.

Anders Behring Breivik

Anders Behring Breivik killed over 90 people in a misguided effort to promote his conservative beliefs about immigration.

Key Takeaways

  • Aggression refers to behavior that is intended to harm another individual.
  • Violence is aggression that creates extreme physical harm.
  • Emotional or impulsive aggression refers to aggression that occurs with only a small amount of forethought or intent.
  • Instrumental or cognitive aggression is intentional and planned.
  • Aggression may be physical or nonphysical.

Exercises and Critical Thinking


Consider how social psychologists would analyze each of the following behaviors. What do you think might have caused each one? Consider your answer in terms of the ABCs of social psychology, as well as the two underlying motivations of enhancing the self and connecting with others.

  • A football linebacker tackles an opponent and breaks his arm.
  • A salesperson repeatedly calls a customer to try to convince her to buy a product, even though the customer would rather he did not.
  • Malik loses all the changes he made on his term paper and slams his laptop computer on the floor.
  • Marty finds her boyfriend kissing another girl and beats him with her purse.
  • Sally spreads false rumors about Michele.
  • Jamie knows that Bill is going to hit Frank when he next sees him, but she doesn’t warn him about it.
  • The U.S. Army attacks terrorists in Iraq but kills Iraqi civilians, including children, as well.
  • A suicide bomber kills himself and 30 other people in a crowded bus in Jerusalem.
  • North Korea develops a nuclear weapon that it claims it will use to defend itself from potential attack by other countries but that the United States sees as a threat to world peace.


Baron, R. A., & Richardson, D. R. (1994). Human aggression (2nd ed.). New York, NY: Plenum Press.

Berko, A., & Erez, E. (2007). Gender, Palestinian women, and terrorism: Women’s liberation or oppression? Studies in Conflict & Terrorism, 30(6), 493–519.


Bushman, B. J., & Anderson, C. A. (2001). Is it time to pull the plug on hostile versus instrumental aggression dichotomy? Psychological Review, 108(1), 273–279.

Craig, W. M. (1998). The relationship among bullying, victimization, depression, anxiety, and aggression in elementary school children. Personality and Individual Differences, 24(1), 123–130.

Crick, N. R., & Grotpeter, J. K. (1995). Relational aggression, gender, and social-psychological adjustment. Child Development, 66(3), 710–722.


Horgan, J. (2005). The psychology of terrorism. New York, NY: Routledge.

Kruglanski, A. W., & Fishman, S. (2006). Terrorism between “syndrome” and “tool.” Current Directions in Psychological Science, 15(1), 45–48.

McCauley, C. (Ed.). (2004). Psychological issues in understanding terrorism and the response to terrorism. Westport, CT: Praeger Publishers/Greenwood Publishing Group.

Olafsen, R. N., & Viemero, V. (2000). Bully/victim problems and coping with stress in school among 10- to 12-year-old pupils in Aland, Finland. Aggressive Behavior, 26(1), 57–65.


Potok M. (2010). Gays remain minority most targeted by hate crimes. Intelligence Report, 140. Retrieved from http://www.splcenter.org/get-informed/intelligence-report/browse-all-issues/2010/winter/under-attack-gays-remain-minority-mos.

Sharp, S. (1995). How much does bullying hurt? The effects of bullying on the personal well-being and educational progress of secondary aged students. Educational and Child Psychology, 12(2), 81–88.
