Aggressive behavior often poses problems in humans across the life span, both as initiators and recipients of aggression. The study of the causes of and methods to reduce aggression is vital, especially with regard to the psychological development of children and adolescents.
Aggression is a verbal or physical behavior that involves delivery of a noxious stimulus (e.g., an insult, a punch) to another person with the intent to harm that person. Aggression is not assertiveness, such as standing up for oneself, and it is not accidental. Violence is extreme aggression that usually results in severe injury to the recipient. There are four main types of aggression: (1) impulsive, which occurs without thought and usually when the person is uncomfortable (e.g., feels hot); (2) retaliatory, which occurs in response to provocation (such as a slap from another person); (3) instrumental, which is when a person aggresses to attain another goal, such as hitting in order to get a desired toy; and (4) angry, which is when the person experiences anger while aggressing.
Causes Of Aggression
Four of the most heavily studied situational causes of aggression are when a person (1) is verbally or physically attacked, (2) perceives that he or she is being blocked from obtaining a goal and feels frustrated, (3) feels physically uncomfortable or in pain, and (4) is exposed to violent media. Insults and physical attacks from others are, of course, a main cause of retaliatory aggression. Research has clearly shown that situations that evoke frustration, such as when a person cannot solve a jigsaw puzzle or when the car in front of a person fails to move after the traffic light turns green, often result in increased aggression. Frustration effects on aggression are exacerbated when coupled with a provocation (e.g., an insult).
Similarly, uncomfortable environments, such as those that are hot, painful, or noisy or that cause sleep deprivation, also often result in enhanced irritability and aggression. For example, many archival studies of the relation between heat and violent crime (i.e., murder, rape, assault) have found that hot days, months, years, and locations are associated with higher violent crime rates than are comfortably cool days, months, years, and locations. Aggression is less likely to occur in uncomfortable situations if the individual thinks that he or she can control the cause of the discomfort. For example, when participants are given opportunities to turn off a loud noise, they act less aggressively than participants exposed to noise that they cannot turn off. Often, the aggression that results when a person is uncomfortable is impulsive; the person “lashes out” at another person without provocation.
Watching violent television and movies, playing violent video games, and listening to music with violent lyrics have all been shown to increase aggressive thoughts and feelings and sometimes result in aggressive behavior. Early research on media violence revealed significant positive correlations between watching violent television and aggressive behavior, but these findings were criticized because the correlational nature of the data did not allow for conclusions to be drawn about the causal role of violent television. That is, these studies found that people (mostly school-age children) who watched a lot of violent television were reported as acting more aggressively by peers, parents, teachers, and even the children themselves, than those who watched less or no violent television programs. However, the higher aggression in those who watched violent television could be explained by many other causes, such as that people with aggressive personalities tend to aggress more (and also tend to watch violent television).
Media violence research over the past three decades has been more methodologically sophisticated and has included experimental designs that control for all other potential causes of aggression and test exclusively the effects of viewing media violence. The conclusion from these studies is clear: exposure to violent media (e.g., television shows, movies, music lyrics, video games) increases aggressive thoughts and angry feelings and may increase aggressive behavior. Young children are especially susceptible to these effects because they are highly likely to imitate aggressive (especially same-sex) models and because they cannot easily discern fantasy from reality. Imitation effects of violent video games are particularly problematic because of the active physical and psychological engagement with the games as well as personal identification with the characters. New
research has found that even video games rated “for everyone” (as well as those labeled “for mature audiences only”) have been associated with increased aggressive behavior.
Many researchers who have studied and theorized about aggression are social psychologists who focus on the roles of situational factors and underestimate the effects of factors about the person such as aggressive personalities and biological and genetic predispositions. Therefore, early theories of aggression mostly assumed that aggressive behavior is not consistently expressed across the life span; rather, it is evoked by some external stimulus.
The assumption that aggressiveness is not a stable disposition across the life span changed when Olweus published a review of several longitudinal studies that measured aggressive behavior of children of different ages across time. Several studies found that 3-year-old children differ in aggressiveness and that the intensity and frequency of their aggressive acts at age 3 were similar to the intensity and frequency of aggression 12 to 18 months later. Aggressive children between the ages of 8 and 9 aggressed at similar rates 10 to 14 years later. Olweus also found that 12and 13-yearolds aggressed at a similar rate and in similar ways for 1 to 5 years. These findings, however, should not be interpreted as meaning that certain people are aggressive most of the time. Alternatively, Olweus suggested that aggressive dispositions (or personalities) interact with both situational factors and the person’s interpretation of the situation to predict (and produce) aggressive behavior.
Boys and girls have been found to differ in the type of aggression that they display, and these sex differences are attenuated by age. Several studies have found that boys tend to engage in more “direct” physical or verbal aggression against a target. Girls have been found to engage in more “indirect” aggression, which involves manipulations of social networks to isolate or otherwise psychologically harm the target. Sex differences in indirect aggression have been found in 8 year olds and more so in 11 year olds, when social skills are more developed. Sex differences in adult aggression are less pronounced, but the same pattern of the direct and indirect types of aggression have been demonstrated. Studies on the intensity of displayed aggression have revealed that males tend to act more aggressively than females when they are not provoked by another person, but when provoked, women are as aggressive as men. Women are also as aggressive as men when the aggression is displayed in written or verbal forms (rather than in physical behavior).
Testosterone levels have also been shown to positively relate to expression of aggressive behavior in both men and women. Decreases in estrogen and progesterone, which occur in the premenstrual phase of the menstrual cycle, are similarly associated with an increase in aggressive behavior. Some genetic factors have been found to relate to aggression, such as the high proportion of males incarcerated in prison for committing violent crimes who have an additional Y chromosome (i.e., they have an XYY genetic chromosomal makeup).
The way that people cognitively interpret potentially provoking situations has further been shown to predict aggression. Child and adolescent bullies tend to be less capable than nonbullies at correctly understanding other people’s intentions in social situations. Bullies often assume that others are threatening them when they are not and respond “in kind” by aggressing. This tendency has been labeled a hostile attribution bias because such individuals tend to falsely attribute hostile intent to other people’s actions.
Men and women have also been found to differ in their interpretations of their own aggressive behaviors. Men tend to view aggression as an effective way to control other people in order to attain interpersonal or other goals and often report the aggression as satisfying. Alternatively, women tend to view their own aggression as uncontrolled emotional behavior and feel guilty and remorseful for their inability to suppress the emotional outburst.
Main situational causes of aggression are verbal and physical provocation, frustration, physical discomfort, and violent media exposure. Person causal factors include an aggressive personality, which is often consistent across the life span, and genetic and biological factors such as testosterone levels and presence of an extra Y chromosome. Males tend to engage in direct aggression and females in indirect (or manipulative) aggression, and when women are provoked, they may be as aggressive as men. Finally, cognitive interpretations of potential threats affect whether or not individuals respond aggressively.
Theories Of Aggression
One of the earliest theories of aggression is the frustration-aggression theory, which states that frustration always causes aggression and that aggression is always caused by frustration. Research has since clarified that this theory is too restrictive; although frustration is a main cause of aggression, it does not always precipitate aggression, and frustration is not necessary for the expression of aggression.
Social Learning Theory
Social learning theory, a meta-theory of psychology that provides an elegant explanation of learning processes, was first applied to describe why children repeat the aggressive behavior that they witness. Children often imitate aggressive behavior that has been modeled by another person (particularly if that model is of the same sex as the child and if the model is rewarded for aggressing, called vicarious reinforcement). Children are less likely to engage in aggression when they observe a model receive negative consequences for aggressing (vicarious punishment).
The cognitive-neoassociation theory posits that thoughts, feelings, and behavioral tendencies are stored together in memory networks analogous to spider webs. Exposure to an aggressive stimulus (such as a picture of a weapon or a provocation) can automatically bring to mind hostile thoughts and angry feelings and can increase the likelihood of an aggressive response.
Excitation Transfer Theory of Arousal
According to the excitation transfer theory of arousal, people are more likely to act aggressively when they are physiologically aroused, especially when an aggressive stimulus is present (e.g., during or after exercise, or following ingestion of a drug that enhances central nervous system activity). For example, if a person is insulted after exercising, then their physiological arousal can be “misattributed” to anger toward the insulter rather than to the exercise, and the person may feel more intense anger and aggression propensity than would a nonaroused individual.
General Aggression Model
The general aggression model (GAM) is one of the most comprehensive theories of aggression in that it consolidates the components of each of the previously described theories with the effects of person variables that have been correlated with aggressive behavior. The GAM posits that both situational (e.g., frustrating events or viewing of weapons) and person (e.g., attitudes endorsing violence) factors can independently or jointly cause an increase in aggressive thoughts, feelings, and physiological arousal. According to the GAM, when aggressive thoughts, feelings, or arousal are enhanced, the person then either engages in a rapid, immediate appraisal of the situation (e.g., “she shoved me, and I am going to shove her back”) or in a more deliberate, thoughtful appraisal of the situation, in which they think about potential causes of the aggressive stimulus (e.g., “perhaps she shoved me by accident”) and about the potential costs or rewards associated with aggressing.
If the person does not have the time or motivation to think about the causes of the aggressive stimulus or the potential negative consequences of aggression, then the person is likely to engage in impulsive aggression, often very quickly. If the person does think about the causes and possible consequences of their actions, then they are more likely to engage in thoughtful deliberative behavior that may or may not be aggressive. The “target” person in the social interaction who “receives” the aggressive or nonaggressive response then will respond in some way, which influences the other person’s beliefs and may serve as yet another situational stimulus (e.g., a provocation) that can again initiate the cycle described.
Five theories of aggression are presented: frustrationaggression, social learning, cognitive-neoassociationism, excitation transfer theory of arousal, and the GAM. The first four theories focus on different causal mechanisms, namely frustration, imitation, priming of aggressive thoughts, and misattributing physiological arousal to a feeling of anger. The GAM incorporates the tenets of each of these theories and provides a comprehensive framework for understanding how situational and person factors affect aggressive thoughts and feelings that result in impulsive or deliberative aggression (or refraining from aggression).
Aggression And Child-Rearing Practices
Early life experiences and the environment in which children are raised can influence and inhibit aggressive responses. Studies of child-rearing practices have shown that positive parent-child relationships, reasonable discipline, appropriate supervision, open communication, and modeling prosocial family values and behaviors all contribute to protecting children from acquiring aggressive and problematic behaviors.
Researchers of early childhood development generally agree that the responsiveness of caretakers and their relationships with children in their care are important predictors of children’s social competence, coping skills, and ability to form close friendships and intimate, nonaggressive relationships. Securely attached children have protective factors that act as social and emotional buffers against many risk factors correlated with aggression. Preschoolers and young children from stable and emotionally supportive caregivers possess higher levels of self-esteem, demonstrate higher levels of appropriate self-reliance and reality testing, respond more empathetically to others, and are more socially adept and accepted by others. Additionally, social scientists have shown that adolescents and young adults from nurturing parental figures form caring and healthy friendships with both sexes and experience intimate relationships in which both positive and negative affective states are explored and expressed nonaggressively.
Conversely, preschoolers and young children with hostile or rejecting parental figures tend to respond aggressively and with anger to younger siblings and peers, and later in life relationships. Children who experienced unpredictable and insensitive parents were shown to become anxiously needy and angry, characteristics highly correlated with aggressive behavior, such as jealousy, competitiveness, and possessiveness.
Child-rearing practices in which parental figures are both abusive and neglectful create a high probability that these children will view the world as dangerous, rejecting, unpredictable, and unavailable to meet their needs. Feelings of anger and fear have also been shown to predict aggressive dysfunctional coping strategies in children (i.e., controlling through bullying, threatening, and other forms of aggression). Additionally, mental health problems such as depression, anxiety, and conduct disorders have been positively correlated with abusive and neglectful parenting practices.
Child rearing also involves setting boundaries, providing adequate supervision, and disciplining children. Parental characteristics such as age, socioeconomic conditions, marital status, and larger family size relate to parental discipline styles. To establish desirable nonaggressive behavior, researchers have demonstrated the importance of reinforcing targeted nonaggressive behaviors. Some forms of punishment can engender feelings of anger and shame and arouse a desire for revenge, highly connected with aggression and violent behavior.
Corporal punishment has been demonstrated to have both short and long-term negative effects on children, including the development of antisocial behaviors. An important longitudinal study found that children were more likely to engage in aggressive behaviors if subjected to severe physical discipline, particularly when other early social and emotional needs were not met. Although corporal punishment remains a parental right, the practice has largely been abandoned by educational institutions and is illegal in a little more than half of the states in the United States. Adult corporal punishment of children is legally considered a form a child abuse in several countries around the world.
Child-rearing practices that promote nonaggressive behaviors include positive parent-child relationships, modeling healthy and nonviolent responses to conflict and stress, monitoring children’s behaviors, establishing boundaries and expectations for children, and communicating prosocial family and community values.
Role Of Peer Relationships And Aggression
It is long established that peer relationships of children, along with family context, are critical factors in evaluating the developmental trajectories of aggression in children. Researchers have been interested in several types of social peer interactions, specifically friendships, mutual antipathies, rejection by peers, and bullying and peer victimization.
Friendships are based on reciprocal liking and equality. Beginning at an early age, peer relationships establish a model for future adult relationships while providing social and cognitive developmental skills. Friendships provide a multitude of benefits, including resource sharing, collaboration of ideas, mutual trust, feedback, feelings of belonging, and entertainment. It is not clear whether well-adjusted children are more likeable or if friendships contribute to helping children become socially competent. Nevertheless, friendships and social affiliation are positively associated with nonaggressive behaviors in children and are predictive of future relationships.
Friends also exhibit aggressive behaviors such as verbal or physical fights. However, this form of aggression is characteristically not as forceful; the parties reunite after fighting, and the role of aggressor alternates. Some researchers suggest the ability to make and maintain friendships is the best predictor for healthy adult adaptation.
Relationships Involving Rejection and Mutual Dislike
Children experience rejection by peers as well as relationships involving mutual dislike. Studies show both types of relationships are common. However, research in this area of peer relationships is sparse, and the outcomes from studies are mixed. Children who experience rejection when other factors place them at risk (such as violent neighborhoods and poor family relations) may turn to aggressive outlets. Further, inimical peer relationships may place children at greater risk for exhibiting aggressive behaviors because conflicts and confrontation may lead to violent expression. However, socially adept children experience rejection and have antipathies without harmful effects or signs of aggressive responses. In fact, in both male and female relationships, enemies may inhibit aggressive behavior. The findings are not conclusive, and future studies of relationships between enemies will likely examine such factors as communication patterns, relationship importance, the circumstances and dynamics surrounding animosity, and the emotional consequences of rejection and conflict in peer relationships.
Bullying and Peer Victimization
As a result of an increase in violence in primary, secondary, and high schools worldwide, peer relationships characterized by bullying and peer victimization have received international attention. Bullying, generally carried out in small groups, consists of verbal humiliation, physical assaults (including sexual assaults), and social ostracism. Researchers generally agree the primary motivator for bullying is power and a strong desire to achieve some material or social reward. Studies have found bullying behaviors (without intervention) persist into adulthood and may be a source of depression, physical illnesses, anxiety, substance abuse, and academic failure.
Peer relationships involving bullying behavior, once believed to be a male phenomenon, appear to be common to both sexes. Although males tend to use more direct forms of aggression such as hitting and biting, even against females, older children and females generally employ indirect relational aggression such as spreading rumors and encouraging others to exclude peer victims. These types of behaviors, evident during early childhood, appear stable over time. Although researchers are uncertain whether male or female tactics are more severe, most victims of bullying do score lower on measures of self-esteem and higher on emotional problems. It is anticipated that exploration of personality development, environmental factors, family relationships, attitude formation, and cognitive development in bullies and victims will contribute to programs implemented in schools to prevent these negative peer relationship patterns.
Peers exhibit aggressive behaviors in their relationships. Some aggression is normal and part of the socialization process, whereas other behaviors are injurious and developmentally harmful for children.
Anger And Anger Management Programs
Anger is a natural human emotion with the potential for both constructive and destructive consequences. When channeled constructively, it has been credited with motivating positive life changes, asserting personal and collective rights, and even providing the impetus for creativity. Although some scholars assert anger is never a constructive emotion, almost all would agree that suppressed or explosive anger is destructive and can lead to acts of violence, physical ailments including heart disease and other stress-related illnesses, and psychological symptoms associated with anxiety, depression, and substance abuse. Additionally, suppressed anger has been associated with passive-aggressive behavior, sarcasm, cynicism, and verbal hostility. It is estimated that most people experience anger several times a week. Although most people generally express their anger verbally, about 10% respond with physical aggression.
Anger Management Programs
Programs designed to reduce the expression of anger in unhealthy and violent ways have become a lucrative industry in the United States and around the globe. Legal and educational systems, business enterprises, government agencies, and many other institutions have directed individuals into anger management classes designed to teach participants inner and interpersonal problem-solving and peacemaking skills.
Anger management programs are diverse in course content, format, number of sessions, and theoretical orientations. Although studies have substantiated the value and usefulness of the skills acquired in these workshops, anger management programs are by no means an educational or treatment panacea for every type of anger or every type of angry person. In fact, they are not reliably predictive of outcomes for participants. Ongoing research has identified several important factors currently under investigation, including gender, ethnicity, and cultural differences; environmental factors; readiness and expectations about the program itself; the setting in which the program is delivered; the personal goals of the participants; and the individual’s level of personality trait anger.
Most anger management programs are based on sound psychological principles and instructed by mental health professionals. Although there is a proliferation of anger management programs worldwide, the science lags behind the industry. The American Psychological Association has credited anger management programs as helpful for some participants, whereas the American Psychiatric Association has not made such an endorsement, largely because no diagnostic category for anger exists in the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV-TR). Researchers are trying to establish whether there is a separate set of criteria for such a diagnosis or whether anger is in fact a constellation of many different clinical disorders. Most academic scholars do agree that anger remains one of the most understudied emotions to date.
Anger Management Curriculum
Some anger management programs teach participants to punch pillows, hit punching bags, or otherwise discharge anger in a physically aggressive manner. This practice is predicated on application of the Freudian theory of “catharsis,” which posits that acting aggressively should reduce aggressive impulses by “getting it out of the person’s system.” Paradoxically, research studies have clearly demonstrated that these practices tend to escalate the intensity of anger and fail to decrease aggressive behavior. Acting aggressively toward inanimate objects also strongly associates angry feelings with aggressive responses (i.e., conditioning).
Today, most anger management programs provide instruction in the art of relaxation, problem-solving skills, and cognitive-behavioral strategies focused on changing thoughts and maladaptive behavioral responses. Some programs incorporate conflict resolution techniques, communication training, forgiveness, self-monitoring, and even humor. Although it is fair to say that most anger management programs are psycho-educational in nature, a minority of them are more firmly rooted in traditional therapeutic approaches such as insight-oriented exercises, personality assessments, and self-exploration and family of-origin exploration, especially for individuals with histories of violence. It is anticipated that future programs will be able to tailor anger management programs for each participant rather than providing a generic program. Toward that end, researchers are investigating whether one-on-one training programs are more effective than group sessions.
Definitions and conceptualizations of anger have been debated in the psychological literature, whereas the need for consensus in understanding of the etiology and control of anger is great, both nationally and internationally. Effective anger management programs teach participants to identify angry feelings and divert them into nonaggressive and constructive channels of expression.
Prevention Of Aggression
Because environmental and intrapersonal characteristics factor into the equation of aggression and violence, prevention involves a multidimensional and multidisciplinary approach that begins early in the child’s life. The following types of programs contain key prevention factors that have been identified as important deterrents in developing or expressing aggression in violent ways:
- Early childhood school programs that include early identification of mental health problems, learning disabilities, and behavioral, emotional, or cognitive developmental delays contribute to preventing hostile and aggressive behavior in children (found in longitudinal studies of children in day care and early childhood programs)
- Programs to help parents develop positive parentchild relationships, adequate supervision, consistent and reasonable discipline, and prosocial family values
- Programs designed to assist parents (and other significant adult influences) to become nonaggressive role models for children (including domestic violence prevention programs)
- Programs designed to deter alcohol and drug use in parents and children (because of the strong correlation between drug and alcohol use and aggression)
- Multicultural and gender diversity training programs that provide cooperative work with people who differ, particularly in terms of racial and ethnic background, gender, religion, sexual orientation, and physical abilities
- Educational and employment-related programs designed to help individuals establish economic stability (and parity) because communities with economic hardship are at higher risk for violence
- Programs designed to reduce undesirable amounts of exposure to violent media such as television, movies, music, and video games
- Programs designed to reduce gun availability
Aggression is influenced by situational factors, such as frustrating events and the provocation of others; person factors, such as one’s personality and gender; and the individual’s cognitive interpretation of the situation. Theoretical models of both the causes and methods to prevent aggression reflect these factors. Parental and peer engagement in or abstention from aggression is often imitated by children (and adults) and influence subsequent aggression. Parenting that develops emotionally secure relationships with children fosters less development of pugnacious tendencies in children. Intervention and prevention programs that focus on reducing exposure to aggressive stimuli, such as weapons, violent video games, highly aggressive peers and drugs associated with aggression, and on helping individuals interpret stimuli nonaggressively and not experience enhanced anger, perhaps through the use of relaxation techniques, have been posited as useful in reducing aggression.
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