Genetic + Neural Explanations of offending behaviour

Question 1

what is the AO1 for the genetic explanations

Answer 1

• A specific gene has been identified as being associated with violent crime.
• This so called ‘warrior gene’ effects the production of MAOA.
• MAOA is a chemical which breaks down neurotransmitters such as serotonin and dopamine in the brain.
• The presence of this gene disturbs the production of MAOA, resulting in an abundance of these neurotransmitters in the brain- thought to cause the aggression.

Question 2

what is the AO3 for genetic explanations

Answer 2

• Brunner
• Stuart
• Implications

Question 3

expand on the +ve AO3 point Brunner

Answer 3

• One specific case study has been published which supports the validity of this warrior gene theory.
• Brunner studied a family in the Netherlands with a history of violent aggression in the male line. One man had raped his sister, another had run down his boss with his car.
• Results showed that the warrior gene was present in the members of this family, directly supporting the theory that this gene is implicated in violent crime.

Question 4

expand on the +ve AO3 point Stuart

Answer 4

• Studied 97 men who were going through a treatment programme because they had physically assaulted their wives.
• Men with the warrior gene were the most violent.

Question 5

expand on the +ve/-ve AO3 point Implications

Answer 5

• Some researchers believe that interaction between genes and environment is what can bring out aggressive traits, rather than genes alone.
• i.e. the warrior gene needs to be coupled with some sort of childhood trauma or abuse to determine aggression.
• In America in 2007, a man who had committed a violent murder and was facing the death penalty had his sentence reduced to manslaughter because the defence proved that he carried the warrior gene, and had a history of abuse.
• This case was revolutionary- never before had genetic evidence been used in the criminal justice system in this way.
• This has worrying implications for the future- if more evidence builds for genetic factors in aggression, will more violent criminals have their sentences altered
• What about FREE WILL?!?

Question 6

what is the AO1 for neural explanations

Answer 6

• Evidence suggests there may be neural differences in the brains of criminals and non criminals, current areas of interest are:
• Amygdala – one of the oldest parts of the brain that is key in our ability to regulate emotion. It seems that stimulation of the amygdala results in really violent behaviour, while lesions of this area greatly reduce it
• Frontal lobes –part of the neocortex (neo being “new” in an evolutionary sense), have been linked to higher brain function such as social behaviours and planning.

Question 7

what is the AO3 for neural explanation

Answer 7

• Groves and Schlesinger (1982) +ve
• Wong (1997) -ve
• Raine (1997) +ve

Question 8

expand on the +ve/-ve AO3 point Groves and Schlesinger

Answer 8

• found that amygdalectomy (surgical removal of the amygdala) reduces aggression in previously violent individuals.
• This supports the idea that amygdala plays a role in aggressive behaviour.
• BUT…

Question 9

expand on the -ve AO3 point Wong

Answer 9

• found reduced amygdala size and activity in violent criminals.
• This seems to contradict the findings of Groves. Groves found removing the amygdala removes violence. Wong found the most violent criminals had a smaller amygdala.
• Therefore the exact role of the amygdala is still unclear!
• What we do know for sure is that the amygdala plays some sort of role in aggressive behaviour.

Question 10

expand on the +ve AO3 point Raine

Answer 10

• identified abnormally functioning brain regions specific to offenders charged with murder or manslaughter, who had pleaded not guilty by reason of insanity.
• 41 murderers (2 female) given a PET scan to highlight areas of brain activity and these results were compared to an age and gender matched control group.
• Results: They found reduced activity for the offender group in areas such as the prefrontal cortex and corpus callosum (the nerve fibres responsible for swift communication between the hemispheres).
• Additionally, there were abnormalities in the activity of the amygdala.
• This shows that violent offenders have abnormal brain function when compared to normal controls.
• Results suggest that the brains of offenders are slowed and unable to make swift decisions to react appropriately in certain situations, or indeed consider the consequences of their actions in order to control their behaviour.