Aggression is simply defined as “Any form of behavior directed toward the goal of harming another living being who is motivated to avoid such treatment.” Aggression is most commonly studied in its application to humans and may include both verbal confrontations and physical gestures. Singular aggression between two humans is the most typical form of aggression found in the social world. The most destructive occurrence of aggression is found in warfare between sovereign nations. Numerous studies and analyses of the many forms of aggression reveal a host of potential variables that are social, gender, racial, biological cultural/geographic, psychological, historical, and even situational factors.
Aggression is usually thought of negatively because of its association with harm, such as in assaults and homicides. While this may be the prevailing popular perception, the use or display of aggression is clearly relative to its immediate social or cultural context. Consider, for example, the aggression in competitive sports, such as boxing. The same actions outside the arena are condemned as criminal and requiring a formal response in the form of punishment. The ancient Romans were famous for promoting gladiatorial contests that culminated in the deaths of humans, all in the pursuit of entertainment. Government punishment of criminals is aggression mandated by the state for the purpose of correcting or deterring an assault committed against another citizen. However, in some cultures, it is perfectly acceptable for an individual member to exact justifiable justice or revenge. Among other cultures, aggression may actually be prescribed in response to personal status building or status defense. In our culture, self-defense or defense of another may justify acts of aggression to the extent of causing death. Self-defense as a validation for aggression can clearly be extended to sovereign nations. An act of war or even the threat of war is morally justified because it both defends its people from potential conquerors and prevents a greater harm from a prolonged bloody struggle.
An understanding of aggression begins with a broad examination of human beings and our capacity for aggression. Why should some people have a greater willingness or need than others to display aggression? The study of children is a particularly popular avenue of exploration of aggression. It is commonly understood that the behaviors a child learns (suitable or unsuitable) can become deeply ingrained and carried into adulthood. This behavioral approach maintains that there are three primary sources of influence that shape a child’s behavior and comprehension of appropriate responses: family, peers, and symbolic models.
Households in which the parents do not discipline, are permissive in the child’s expression of aggression, and use power assertion in disciplining tend to produce aggressive children. The family provides the earliest socialization through the interaction of its members, from which the child learns the use of aggressive behaviors and patterns of interaction. The influence of interaction with peers is also very powerful because it provides children the opportunity to learn both aggressive behaviors and vie for, and possibly establish, a coveted position of dominance. Rough play such as chasing, catching, tumbling, and other competitive strength comparison activities provide a usually safe means to learn some of the benefits of aggression, such as victory and peer status/recognition.
Modeling is the third social influence on acquired aggressive behavior in children. Live models are the most common source of childhood-learned aggression, and of all the potential sources, parents are the most powerful and far-reaching. In addition, prolonged observation of aggressive actions causes a gradual desensitization to violence and the pain or suffering of others. Self-modeling is the effect of a child who is the victim of aggression either in the home or at the hands of peers. The child begins to utilize aggression as a means to resolve conflict or in play. The mass media model claims that the effects of observing televised or filmed violence in either physical or verbal forms produces childhood aggression. This model has been under study for several years. The exact impact of viewing aggressive behaviors by children cannot always be accurately predicted because of other confounding variables. However, the effect of any two or all three influences (family, peers, and media) must certainly be significant.
Social factors are certainly not the sole influence on human aggression, because biology may also contribute significantly. Various gender and psychological differences also account for the differences in manifestations of aggression. Much research debate exists over the influence of biology and its impact on human intellect, physical ability, and behavior and especially how it affects human aggression. Debate between those that embrace theories supporting the social causes of human aggression and those that advance a belief in biological influences is commonly referred to as “nature versus nurture.” Some of the most popular biology- based research has been along the lines of heritability and studies of twins, adopted children, and chromosome examinations.
Twins separated at birth have been examined with regard to their histories of aggression and the records of both their natural parents and adopted parents. Research has revealed that adopted children displaying generally aggressive behavior most often shared this same characteristic with their biological father as opposed to a low aggression correlation with the adopted father. This research supports the belief that nature (biology) rather than nurture (environment) has a clear bearing on aggressive behavior.
Studying children has also provided another source for the validation of biological-based explanations into human aggression. The disparity in the aggression levels between boys and girls is well recognized and documented. Research into the type of play that children engage in reveals that boys are more competitive and their play activities tend toward a more physical orientation as opposed to girls. When similar comparisons are conducted on adults, the differences are not as dramatic; however, they are nonetheless identifiable. The disagreement over the causes of gender aggression differences is further complicated by studies of chromosome variation and abnormality. The cells within the human body are comprised of 23 pairs of chromosomes. In females, the pairs are both “X shaped”; in males, the pairs contain one “X” and one “Y-shaped” chromosome. It is the “Y” chromosome that researchers maintain accounts for males having a greater capacity for aggressive behavior than females. This is commonly referred to as the “Y-chromosome hypothesis.” Consistent with this thesis is the belief that males with the rare “XYY” chromosome abnormality must be especially aggressive and would likely have a criminal history of violence. However, studies of “XYY” males in prison do not support that particular hypothesis.
There are other potential influences on aggression not directly attributable to social or biological factors. We must understand that some individuals are more affected than others by these influences. The first of these effects is temperature, specifically hot temperature. It is widely recognized that assault offenses increase during the summer months, and within heat wave periods, individual irritability can be particularly elevated. Noise levels can also impact aggression. The significant contributors to noise are naturally located in the more urban areas: automobile movements, industrialization, and airplane traffic. Increased noise levels have been associated with reduced interpersonal interaction as well as a decrease in citizens helping others and less sociability. Associated with noise is the influence of crowds or high-density populated geographic areas. The studies that have been conducted are inconclusive with respect to what particular quality of crowds causes increased aggression. However, it has been determined that males are more affected than females.
- Baron, R. A., & Richardson, D. R. (1994). Human aggression. New York: Plenum Press.
- Humphrey, A. P., & Smith, P. K. (1987). Rough and tumble, friendship, and dominance in school children: Evidence for continuity and change with age. Child Development, 58.
- Mednick, S. A., Gabrielli, W. F. Jr., & Hutchings, B. (1987.) Genetic factors in the etiology of criminal behavior. In S. A. Mednick, T. E. Moffitt, & S. A. Stack (Eds.), The causes of crime: New biological approaches. New York: Cambridge University Press.
- National Research Counsel. (1993). Understanding and preventing violence. Washington, DC: National Academy Press.
- Perry, D. G., & Beussey, K. (1984). Social development. Englewood Cliffs, NJ: Prentice Hall.