Chemistry Recruitment

For hundreds of years,some scientists have held that criminality is inherited. In the nineteenth and early twentieth centuries, it was believed that faulty genes were responsiblefor criminals and consequently, they should not be allowed to reproduce[1]

This was an attractive proposition as it meant that the issue could easily besolved by persecuting current criminals and their offspring. Although outdated,some geneticists are still keen that in the future we might be able to test ourunborn children for their criminal profile.

Over time, it has been recognised that it just cannot be that simple and most now hold that the push factors to commit crime are numerous. However, there are groups of individualswho still hold t hat the preference to commit crime is pre-determined before ourbirth.

Here’s some of the evidence:

·              Chemical imbalances - Genetic testing donein prisons shows that many male prisoners have XYY chromosomes. This can cause chemicalimbalances and is entirely genetic.[2]It could indicate some genetic pre-disposition to crime or violent behaviour.

·              Studies done withviolent and criminal families have shown genetic mutations in particular chemicals in the brain. These can lead to fluctuations in certain chemicals,resulting in impulsive and aggressive behaviour.[3]

·              Twin studies - Studies of identicaltwins, separated and adopted at birth, show that individuals tended to actsimilarly to their twin in both childhood and adult anti-social behaviour,despite never growing up together. 50% of identical twins with criminal recordshave twins with criminal records. Only 25% of fraternal twins both have records[4]

·              Adopted individualswho were born to incarcerated women have higher rates of criminal convictions as adults[5]

·              Traits that influence criminal behaviour- Eysenck developed the PEN Model, which looked at how psychoticism,extraversion and neuroticism affected our likelihood to commit crime. He found that extraversion was a predictor for young people and neuroticism a predictorfor older people. These traits are known to be heritable.[6]

·              Genetic mutations - Guang Guo led a teamstudying a variation of a particular gene. He said that only 1% of people havethe mutation but they are very prone to delinquent behaviour[7]

Creating a criminal – The impact of environment

Other theorists hold that it is predominantly environment that determines whether someone will commit crime. The basic premise here is that if no one learnt about crime then no onewould do it. The cause of criminals is the criminal and underprivileged worldthat they are born into. Environmental cause may also be outside the familysuch as peers, poverty, schooling, deprivation, neglect and abuse.

 Here’s some of the evidence for environmental impacts:

·          Peer pressure - Studies on the effectof peers on children show peer pressure plays a key role in behaviour. However,99% of studies show that this is only true of boys[8]

·          Family influence - Children from familieswith weaker bonds and less communication are more likely to develop aggressiveand criminal behaviour[9]

·          Children whoexperience abuse or neglect are 50% more likely to turn to crime[10]

·          Nurture affects nature - Whilst particularpersonality traits may correlate with tendencies for criminalism, not everyonewho has them become criminals. The determining factor in whether those traits turn to delinquent behaviour is environmental. 

·          Whilst some geneticvariations are associated with poor behaviour, many are only triggered when an individual has also experienced stressful situations.

           For example, a mutationin the gene DRD2 is linked to delinquency in boys but only when they do nothave meals with their family. The same mutation in boys who regularly havefamily meals does not increase the risks of delinquency[11]

·          One type of criminal? - There may be morethan one ‘type’ of criminal. For example, if you look at sociopaths, there isno reason why some are primarily determined by their genetic make up and others by their upbringing and experiences.[12]

In conclusion

There are no clear answers in this area and it is unlikely that there will be any wayof truly separating the contributions of genetics and environment – well, not without some pretty unethical experiments!! The subject is complex preciselybecause people are complex and that is why our job of understanding them can be so difficult!