There are two main methods of research that are used by researchers to explain genes and heritable influences of genes, methods include twin and adoption study. The theory of twin study is that monozygotic (MZ) twins are more likely to behave similarly as compared to dizygotic (DZ) twins because MZ twins share 100% of the genetic makeup. Numerous studies have been conducted with twins with all showing that identical twins have greater similarity in behavioural pattern as compared to fraternal twins (David 1970). But there is a critical issue with twin study which involves social environment. Christiansen (1974) conducted a study of twin and discovered that if one identical twin was registered as offender there was 32% probability that other twin would also be registered as offender but it was only 12% for fraternal twins. Although this proves that identical twins are likely to behave similarly but this kind of twin study fails to account environmental factors. One way to possibly control that factor is adoption study with twins. Adoption study hypotheses is to determine if identical twins separated at birth growing in different social environments still have similar behavioural pattern as compared to fraternal. It is now believed that there is some evidence when considering all factors in account that identical twins share similar behavioural patterns and that hereditary plays a vital role in criminality (Walters, 1992). Family study is also a theory underlying heredity as an explanation however again due to social environmental factors, it’s a study rarely used by researchers.
After genetics, neurology explains criminal behaviour from a very different view point. Neurology theorises that neurotransmitters are chemicals produced by human body which allows for the transmission of electrical impulses within the brain which and are the basis of brain processing information. This also determines all types of behaviour for example criminal and antisocial behaviour. Neurological view also underlines that serotonin, dopamine and norepinephrine are three main types of chemicals that determine antisocial behaviour in criminals and vary dependant on levels of chemical present (Brennan, 1995). A detailed study conducted concluded that neurotransmitters are initially determined by genetics but can be influenced by drugs, alcohol and lithium carbonate. The study itself failed to determine weather antisocial behaviour is a direct result of manipulation of certain chemicals that effect brain (Scerbo)
Hormones are also one of widely studied topics in biological view to explain crime. The role of testosterone and its relationship with aggressive behaviour still remains to be understood. There are various different problems with study of testosterone and aggression for example instead of testosterone causing increased aggression, aggression may also cause increased level of testosterone. Social variables may also intervene in the relationship between testosterone and antisocial behaviour. From critic point of view it can be argued that although there is a strong relationship between testosterone and deviance but scale of this effect is reduced significantly when controlling social integration and reduced social integration can also result in higher deviance level (Raine, 1992). Most of hormone and crime research involves male study but not much work is conducted on female hormones and menstrual cycle.
Over centuries the most fundamental issue that is raised is whether criminal behaviour is a product of nature or nurture. Theorists have always removed one or the other viewpoint from the issue. A growing debate over last two decades is if the answer lies somewhere in between nature and nurture. With development of human genetics one thing is clear that some behavioural patterns are direct result of biology therefore it is both, hereditary and environmental factors that play a role on human’s intelligence, personality and behaviour. No single theory can provide all the answers for criminality but when all the theories are combined they give a much clearer picture. There are many more theories than the ones mentioned here, all of which may be relevant to the causal explanation of crime. The nature versus nurture debate is something which goes on in many disciplines and will continue to do so.
Biological explanation for crime offers some interesting finds but such justification in study of crime precludes the possibility of freewill. The fear of acceptance of such explanation in explaining crime has resulted in biological explanation being rejected. This also sparked a new debate which stands along side nature or nurture and is known as free will or determinism. Suzette Cote in her explanation for crime theorizes that “The theory of conditional free will predicts that if one or more conditions to which the individual is exposed are disturbed or irregular, the individual is more likely to choose more disturbed or irregular course of action.” What she meant is that although genetic makeup explains for some irregularities in human behaviour yet certain social environmental factors along with certain genetic factors combined cause individual to behave in antisocial manner. A very comprehensive study was conducted bearing in mind factors like social environment, biological make up on explanation criminal behaviour, juvenile delinquency and disciplinary problems. The study created a model which was capable of predicting 25% future adult criminality in males and 19% future criminality in females. However this can also be contested, that behaviour should be predicted in terms of a series of probabilities of expected behaviour, not in terms of cause of an effect (Denno, 1998).
In conclusion biological theories and advanced medical science only help us improve our knowledge in understanding criminal behaviour but they do not provide enough sufficient and adequate evidence that can explain causation of crime entirely. Biological prospective allows for better understanding rather then full explanation, for example harmonic study and testosterone only explains for some aggressive behaviour but fails to explain whether that deludes free will, we are responsible for every human action we take. I believe that genes, heredity, hormones, neurology are all aspects that play a vital role in human behaviour but cannot account for all criminal or deviant behaviour because there is no evidence to suggest if this is the case. Moreover, all studies and research methods cannot entirely relate antisocial behaviour with biological make up because not all studies account for environmental and external factors. This shows that biological and sociological aspects combined can explain causation of crime better then just simply narrowing such a complex phenomena of criminal behaviour down to one simple aspect. Statistically resent findings to date clearly identify that biological involvement in antisocial behaviour is only one aspect. “Society is closer to enacting prevention programs aimed at population who are at risk of exposure to biological and scioenviromental hazards that are known to increase the incident of behavioural problem” (Suzette, 2002). Other models such as life span development of health and illness have also proved helpful in understanding crime. Life span approach highlights many different types of advantages for advanced understanding of health related outcomes, including its ability to address sensitive and critical period issues regarding health. A life span perspective is especially appropriate even essential for the study of health because of relative health and risk for illness change throughout the lifetime with each stage of life span influenced by past events and affecting future outcomes. This kind of study accounts all major factors such as social, environmental and biological, and I believe this model will help explain causation of crime better and help us understand crime with all factors considered.
Lombroso, Cesare. “introduction,” to Gina Lombroso ferrara, criminal man according to the classification of Cesare Lombroso. 1911
Fishbein, Diana H. “biological Perspective in criminology,” Criminology 28 (Feb 1990), 27-72.
Jones 1991
David Rosenthal, “genetics theory and abnormal behaviour among twins.” 1970, pp 225-36
Christiansen, K O. “seriousness of criminality and concordance among Danish twins” 1974.
Walters, Glen D. “a Meta-Analysis of the Gene-Crime Relationship.” Criminology (1992)
Brennan, P. A, S. A Mednick, and J. Volavka, “biomedical factors in crime” 1995
Scerbo. A and A. Raine, “Neurotransmitters and antisocial behaviour: A meta-analysis”
Raine, Adrian, the psychology of crime “hormones and aggression” 1992
Suzette Cote, “criminological theories, bridging the past to the future” 2002
Denno, D. W. (1998). Human biology and criminal responsibilities: free will or free ride?
