Biological Factor Influence Criminal Behavior

Biological factor influence criminal behavior: The study of criminal behaviour and how it originates comes from three main sources: Twin studies, adoption studies and family studies. Most effective studies when monitoring criminal behaviour are seen through twin studies using monozygotic (MZ) twins since they have the same DNA. Twin studies are therefore used to support the contention that there is a biological heritable factor which increase the risk for criminal behavior. Twin studies compare the results of the criminal behaviour of genetically identical twins, versus the results of dizygotic twins (DZ) in order to determine the role of genetic or environmental influences. Source If the crime rate of the observed monozygotic twins is higher

First and foremost it is important to note that it’s very difficulty separate the genetic influences alone from the environmental influence (social). Meaning that even though the subjects do show a genetic factor which influences criminal behaviour there are many other social influences such as the relationship with the family, economical statues, and environment that they had grown up in. Along with this, it is very hard to know and determine whether the MZ twins that were used in the study had the same type of social environment with the same treatment, or if the they had varying, since this would majorly affect the results. The hardest condition but the one that would most significantly support the genetic influence on criminal behaviour would be a correlation between MZ twins and criminal behaviours from varying environments, meaning that one of the twins was from a suitable household, while the other was from a deprived environment. This condition was present in Christensen study which adds more credit to the study, but not enough of these conditions were noted. Another weakness of this study is that It can also be argued that MZ twins are usually treated similarly while DZ twins can include one of the twin pairs to be male and the other a female which of course leads to a different upbringing. However strengths of this study is that

Barnes conducted research, with his colleagues, analysing criminal influences in 4,000 people, which was based on the 1993 theory of Duke professor Dr. Terrie Moffit, which states that people will generally fall into three separate and different types of categories when it comes to criminality and criminal behavior. The first category consisted of life-course persistent offenders (lifelong criminals) and contain individuals which are considered to be genetically predispositioned for crime. The second group contained adolescent-limited offenders, or rather people who grow out of their bad behavior. J.C Barnes states that these people from the second group broke out of their bad habits after experiencing a traumatic or eye opening event (possibly prison). Lastly there are law-abiding abstainers (non-criminals) group. Along with Lombroso’s findings this paper supports and shows that for persistent offenders genes are the main influence which cause criminal behaviour. In contrast to this, adolescent-limited shows that environnement is the main and only factor, and for the abstainers it’s a roughly equal split, this meaning that both genetic and environmental factors played an important