Biological: Genetic Explanation

Question 1

What is the genetic explanation of criminal behaviour?

Answer 1

Would-be offenders inherit a gene, or combination of genes, which predispose them to commit crimes.

Question 2

How do twin studies demonstrate the genetic explanation of criminal behaviour?

Answer 2

They show that MZ twins have a greater concordance rate than DZ twins (with reference to crime rates) and they have more common DNA suggesting there is a genetic basis and DNA causes criminality.

Question 3

What are the ‘features’ of the genetic explanation?

Answer 3

• Twin studies.
• Adoption studies.
• Candidate genes.
• Diathesis-stress model.

Question 4

What is the diathesis-stress model?

Answer 4

An explanation of a disorder through the interaction of nature and nurture, the diathesis is the innate gene that causes a vulnerability whilst he stressor is an external event which activates the gene.

Question 5

Name some twin studies that support the genetic explanation:

Answer 5

• Lange (1930).
• Raine (1993).
• Christiansen (1977).

Question 6

How can the diathesis-stress model be used to explain offending behaviour?

Answer 6

The criminality genes may be passed down whilst the behaviour remains dormant. A certain event can act as a stressor or the gene can be left dormant as it is passed down.

Question 7

Describe the twin study of Lange (1930):

Answer 7

Lange (1930) investigated 13 MZ and 17 DZ twins, one twin in each pair had served time in prison. He found that 10 MZ and 2 DZ twins had BOTH been in prison.

Question 8

Describe research into candidate genes?

Answer 8

Tiihonen (2014) conducted a genetic analysis of 900 offenders and found abnormalities on 2 genes that may be associated with violent crimes.
These are the MAOA gene and the CDH13 gene.
In this sample, those with these genetic abnormalities were 13 times more likely to have a history of violent behaviour.

Question 9

Tiihonen found abnormalities of which 2 genes?

Answer 9

MAOA gene and CDH13 gene.

Question 10

What is the MAOA gene?

Answer 10

A gene which controls dopamine and seratonin levels in the brain and is linked to aggressive behaviour.

Question 11

Describe the twin study of Raine (1993):

Answer 11

Raine (1993) reviewed research on the delinquent behaviour of twins and found 52% concordance for MZ twins and 21% for DZ twins.

Question 12

Which adoption study has demonstrated a genetic explanation?

Answer 12

Crowe (1972) found that adopted children who had a biological parent with a criminal record had a 50% of having one by the age of 18, whereas adopted children whose mother didn’t have a criminal record only had 5% chance.

Question 13

What is the CDH13 gene?

Answer 13

A gene linked to substance abuse and ADHD.

Question 14

Describe the twin study of Christiansen (1977):

Answer 14

Christiansen (1977) studied the same using 87 MZ and 147 DZ twins and found 33% of MZ twins had both been in prison whilst only 12% of DZ twins had.

Question 15

AO3: Simplistic.

Answer 15

The explanation has been criticised for ignoring the influence of external factors such as parenting, culture and social learning. This makes the explanation too simplistic and incomplete.

Question 16

AO3: Twin studies.

Answer 16

Twin studies often have small sample sizes which means they may lack validity. Most twins are brought up in the same environment as each other which a major confounding variable. Lange (1930)’s study was poorly controlled and judgement such as zygosity (Mz or DZ) was assessed based on appearance rather than DNA.

Question 17

AO3: Reductionism.

Answer 17

The explanation is biologically reductionist as it links a complex behaviour of crime to a single biological factor. Crime does appear to run in families, but so does emotional instability, mental illness, social deprivation, and poverty.

Question 18

AO3: Determinism.

Answer 18

The notion of a ‘criminal gene’ is biologically determinist, meaning that we do not have any moral responsibility for our actions as they are pre-determined when we are born. This creates a problem with the legal system as it is based on the premise that we have free-will to commit crime and therefore a criminal gene would lead to many legal issues. The existence of a criminal gene could lead to the development of eugenics policies and screenings etc.

Question 19

AO3: Diathesis-stress support.

Answer 19

There is support for the diathesis-stress model of crime, Mednick (1984) studied over 13,000 Danish adoptees. When neither the biological nor adoptive parents had a criminal record, the likelihood of the adoptee having one was 13.5%. It went up to 20% when either of the biological parents did, and 24.5% when both the biological and adoptive parents did. However, we do not know if the crimes they committed were violent crimes or petty crimes such as shoplifting.

Question 20

AO3: Legal defence.

Answer 20

The approach has some legal ramifications, the existence of a ‘criminal gene’ accepted as a legal defence would lead to many people being released from prison for crimes they did commit. The fact that these criminals possess the genes means that they would likely commit another crime as it is out of their control, they are also unable to be rehabilitated as if the behaviour is controlled by genes it cannot be changed by learning.