Mednick, Gabrelli, Williams and Hutchings (1984) conducted a study in Denmark using 24,000 adopted families who were studied over 13 years. They found that biological father and male adoptee conviction rates were higher than those of the adoptee father. Male adoptees and biological fathers were more recidivistic. They also found that there was an association between biological parent’s conviction rates and those of their adopted sons and that environmental aspects influenced social-class crime-relations.
They concluded that there was a strong relationship between the convictions of biological parents and adopted children. However there was no evidence that the types of convictions between the parents and the offspring were related. They also concluded that some factors transmitted by the parents increase the likelihood of conviction and that environmental factors affect the probability of conviction.
Hans Eysenck argued that there are genetic dispositions to crime and that certain character types are more inclined to commit crime. He believed that it was not crime and criminality that were innate, but a balance of cortical arousal in the brain that causes introversion and extroversion. The extraverts need for excitement can lead to anti-social behaviour. He described extraverts as people who were sociable, impulsive and optimistic, whereas introverts are reserved, cautious and controlled.
Eysenck argued that neuroticism is about the intensity of emotional reactions. Those people high on the neuroticism scale tended to be moody, anxious and would over react to stress. He described that the neuroticism-stability continuum relates to the automatic nervous system which produces the ‘fight or flight’ response to a situation. Neuroticism acts as a drive and encourages anti-social behaviour. A neurotic-extravert is the most likely personality type to be involved in criminal behaviour.
Eysenck’s model deserves attention as it is one of few comprehensive statements on the role of genetics in anti-social behaviour. It also recognises the interaction of environment with personality and highlights individual differences in the central nervous system which leads to different personality types.
Michael Rutter, writing in The Independent (15th April 1996,) stated that genes are a ‘code for’ proteins and not behaviour; therefore there is no gene for crime. People vary in behaviour; this is not just based on genes but reflects upbringing and social circumstances. Genes cannot be exclusively blamed for crime; they merely contribute to shaping personality features that may influence certain behaviours that can lead to criminal behaviour.
Dawkins believed that there were no such things as good or bad genes, however genetic influences may work by creating vulnerability to environmental stresses. He used the example of schizophrenia as it involves a strong genetic component. Schizophrenia amongst Afro-Caribbean people in the UK is commoner than any other group and it is more common in the UK than the Caribbean. This showed that Afro-Caribbean’s in the UK had become vulnerable to the stresses of living in the UK despite their genes.
Mullins refers to the lack of support for genetic explanations. He stated that “no one would maintain that the inheritance, whether biological of psychological, can be directly a cause of crime.” However he later observed that “delinquency is closely associated with the lower-grade and mentally deficient.”
There is a long history of socio-biological explanations of crime, yet there is still much to be explored. It is evident that there is no single cause of crime; it is a mixture of biological factors and the environment. A key danger of blaming genes for crime is that criminals can use it as an explanation as to why they committed a crime and may receive lighter punishment. Genes are proteins, not behavioural determinants. It seems that it is more a case of inheriting behaviour from parents rather than actual criminal genes.
