Defend if Humans are Born Violent

Violence in Humans

            With over 1.6 million violence related deaths, violence prevention has become a global concern. Violence due to economic, social and political causes has been extensively studied. However, recently there has been a growing awareness on biological pre-disposition of some individuals to violence. This awareness may explain the individual differences in violence pre-disposition. In this study, it would be paramount to distinguish between predatory violence and impulse reactive violence. The two types of violence have different biological basis. While impulse reactive violence is common among antisocial groups, predatory violence characterizes a small fraction of the populace that is of true psychopaths (Alia-Klein , et al., 2009).

            It is unlikely that humans are directly genetically coded for violence. However, allelic variations are responsible for neurocognitive functioning differences in different individuals (Manuck , Ferrell, Mann , & Muldoon , 2000). The differences in neurocognitive function can then determine an individual’s differential predisposition to violence. Neurobiological factors that contribute to human violence have remained poorly understood. There are several approaches that can be used to examine this topic. This paper shall investigate the different biological theories explaining individual’s predisposition to violence.

Biological Theories of Human Violence

            Violent behaviors are related to a complexity of social and environmental circumstances (Gottschalk & Ellis, 2008). However, heritable factors have widely been implicated in violent behaviors. Firstly, scientists have linked allelic variations found in the X-linked monoamine oxidase A (MAO-A) as an explanation for different individuals’ predisposition to violence. This gene was previously associated with impulsive aggression tendencies in both humans and animals. MAO-A is a key enzyme in monoamines catabolism, especially in catabolism of serotonin (Manuck , Ferrell, Mann , & Muldoon , 2000). Serotonergic systems have been widely implicated in the manifestation of violence and impulsivity in both human and animals. Located on the X chromosomes, MAO-A genes are likely derived from similar ancestral genes. MAO-A genes are comprised of 15 exons, which have identical intron-exon organization, provide the key enzymatic clearing phase for norepinephrine and serotonin during brain development.  A New Zealand study linked low MAO-A activity to violent behavior if the individuals had suffered substantial mistreatments as children. Overall, this approach to human violence suggests that gene alterations on neurotransmitters breakdown may help in understanding an individual’s predisposition to violence (Pavlov & Chekhonin , 2012).

            Another approach of scientific approach has highlighted to dopamine regulating genes. Dopamine is a crucial neurotransmitter that is associated with the rewarding and pleasurable experiences that individuals gain from different activities ranging from drug use to sex. In genetic studies, there are several alleles – a variety of the same genes- that code for the various types of dopamine receptors. Dopamine receptors are distinct locations found on the nerve cells that lock onto the dopamine molecules. DRD2 and DRD4 are distinct types of dopamine receptors that have been associated with increased risk of violent and antisocial behaviors (Gottschalk & Ellis, 2008).

            Genes influencing serotonin – a neurotransmitter – have also been linked to violent behaviors in human beings. High levels of serotonin activity in the brain have been associated with feelings of contentment and calm. Low levels of serotonin activity have been associated with gloom and irritability (Gottschalk & Ellis, 2008). Studies have associated impulsive violence to low levels of serotonin activity in the brain. There are several environmental variables that are associated with regulation of serotonin activities. However, most of the variations are because of genetic factors (Pavlov & Chekhonin , 2012). A conclusion from this approach is that, violent behaviors can be avoided by keeping serotonin levels high.

            Lastly, scientists have linked sex differences to violent behaviors. The chromosomal composition of both males and females is decidedly different. Females lack an entire chromosome, the Y-chromosome, found in males (Gottschalk & Ellis, 2008). This chromosome accounts for the many variations that exist between males and females. It comprises of genes that direct the would-be female ovaries to become the male’s testes. The testes have been shown to evolve into a specialized organ that produces testosterone. Testosterone has been shown to contribute to complex ways of physical aggression in many species (Pavlov & Chekhonin , 2012). However, the tendency to be aggressive is not simply measured by the amount of testosterone present at a given time. It also depends on the amount of androgen receptors – special cell receptors – present in the brain to lock on the testosterone molecules that enter the brain and on the amount of testosterone that gets into the brain before birth (Davidson & Larson, 2000). However, the number of androgen receptors in individuals is under genetic control.

A Critique of Biological Approach to Violence

            These biological approaches of explaining violence tend to reduce violence to a single primary variable. They all give a one-dimensional explanation of violence. However, even though these one-dimensional explanations acknowledge the importance of other variables such as environmental factors, they do not factor them in their analysis and examinations of the situation. The explanations that are given attempt to locate the origins of violence within an individual and do not factor in the social environment. Thus, the explanations derive that some humans are naturally inclined to be violent and hence require little in the form of motivation or stimulation to conduct such violent acts. In this case, violence is taken to be a normative case. However, it may be the case that different forms of violence are both aberrant and normative at the same time.

Ramifications of Using Psychological Principles to Predict Dangerousness

            Neuroscientists have devised methods in which they predict future behavior of an individual (Alia-Klein , et al., 2009). Although such determination is not easy, it does not mean it is impossible to make. Predictions of criminal conduct and violent behaviors have become essential elements in many decisions that have been rendered in criminal justice systems. However, these predictions are not necessarily perfect. The predictions are riddled with compelling tendencies towards over or under predictions of violence. The inaccuracies in these predictions have serious ramifications to both individuals and society. An inaccurate prediction of “high risk” of an individual when the individual is unlikely to commit future violence would result to the restriction of the rights of that individual through criminal or civil commitment or longer sentences. Not only are the individuals labeled “high risk” denied some of their personal rights, but such a label from a clinical terminology attach additional stigma to such individuals.

The other case is when a person is predicted to be “low risk” but then turns out to commit violent behaviors in the future. From such an instance, negative publicity is likely to arise when a connection between the person’s release from a mental or correctional facility and a given violent incident. Such a case would result to lasting negative effects to facility staff in terms of fear of personal litigation, lower morale and distress when they release a person who later ends up killing or seriously harming the society. Therefore, such an inaccuracy does not only harm an institution’s reputation but also the clinician(s) who undertook the assessment and administrators who made the decision to release such an individual.


            In consideration of potential neurobiological correlation of aggression, it is crucial to remember that overt behaviors are expressed in complex interactions of psychological, behavioral and social determinants (Manuck , Ferrell, Mann , & Muldoon , 2000). This implies that the biological explanations presented in this paper should be carefully applied in consideration of all other factors such as the social environment. In other words, the theories that are stipulating the involvement of biological factors are true, but they are incomplete.



Alia-Klein , N., Tomasi , D., Woicik, P., Moeller , S., Williams, B., Craig , I., et al. (2009). Neural mechanisms of anger regulation as a function of genetic risk for violence. Emotion, 9(3), 385-396.

Davidson , R., & Larson, C. (2000). Dysfunction in the neural circuitry of emotion regulation–a possible prelude to violence. Science., 289(5479), 591-594.

Gottschalk, M., & Ellis, L. (2008). Evolutionary and Genetic Explanations of Violent Crime.

Manuck , S., Ferrell, R., Mann , J., & Muldoon , M. (2000). A regulatory polymorphism of the monoamine oxidase-A gene may be associated with variability in aggression, impulsivity, and central nervous system serotonergic responsivity. Psychiatry Res, 95(1), 9-23.

Pavlov, K., & Chekhonin , V. (2012). Genetic determinants of aggression and impulsivity in humans. J Appl Genet, 53(1), 61-82.

Order a Similar or Custom Paper from our Writers