Psychology -Are criminals born or made?

Are criminals born or made?

Biological Explanations

• Twin studies - research into the similarity of twins, particularly their criminal similarity, to investigate genetic links
• XYY - a rare genetic pattern said to be linked to aggression and slow learning ability
• Chromosome abnormality - a mutation of genetic material that results as a change in the number or structure of chromosomes
• Monozygotic twins - identical twins - share the exact same DNA
• Generalised - whether the results can be applied to other people 
• Correlation - a measure of an association or relationship between two factors or variable 

Compare the family trees of criminals and non-criminals - if many criminals have criminal relatives, there might be a biological link

Evidence suggests that individuals are more likely to be criminals if their parents are criminal - however, this could be due to social learning theory or observational learning as families live together

XYY - male chromosome abnormality - causes increased aggression, being taller, and learning difficulties - condition occurs in 1 in 1, 000 male births creating a lack of samples to be certain of the link to violent crime, and just a handful of murderers have been found to have XYY

Adoption studies - people who share genes but not environment isolating genetics (nature) as the cause of criminality 

Christiansen (1977) - twin studies - 3586 pairs of twins - if an identical twin was a criminal, 525 times the other twin was also a criminal - in dizygotic (non-identical) twins the rate was only 22%

Theilgaard (1984) - the criminal gene - wanted to see if criminals had a particular gene that was responsible for their criminal behaviour

Took blood samples from over 30, 000 men born in the 1940s - out of these 16 had the XXY and 12 had the XYY chromosome abnormalities

Interviewed by a social worker, who did not know the aim of the study, about their backgrounds and criminal history

They were given IQ and personality tests 

Findings

XYY males had slightly lower intelligence than average but more aggressive

More similarities between XYY and XXY males than differences

No solid evidence of a criminal gene was found

Evaluation 

• Small sample of men used for the experiment 
• Only 12 XYY males were tested - the findings can't be generalised
• Link between XYY chromosome abnormality and aggression is only a correlation - may not be the cause of increased aggression
• Lower intelligence and delayed speech could have made expression and communication difficult leading to aggressive outbursts
• Tests and interviews were conducted by an independent social worker who didn't know the aim - no researcher or interview bias
• Used a vast range of tests to measure different aspects of the men

Social explanations 

• Conform - to adjust to expectations made of us
• Self-fulfilling prophecy - when the expectations of others influence our behaviour

Childrearing strategies - dealing with naughty children

Induction - parents explain to their child what they have done wrong, why it was wrong and allow them…