Genetic and neural explanations Flashcards
What are the 4 genetic explanations?
Twin studies, adoption studies, candidate genes and the diathesis-stress model.
What did twin studies show?
Lange looked at 13 sets of identical twins and 17 sets of non-identical twins where one twin had served time in prison. Lange found that 10 of the MZ twins had a co-twin also in prison but only 2 DZ twins had a co-twin in prison. This shows there is a genetic basis for offending.
What did adoption studies find?
Crowe found that adopted children who had a biological parent with a criminal record were at a 50% risk of having a criminal record. Children whose parents didn’t have a criminal record only had a 5% risk.
What did research into candidate genes find?
Tiihonen looked at 900 offenders and revealed abnormalities in the MAOA gene, which has been linked to aggressive behaviour, and CDH13, which has been linked to substance abuse and ADHD. Within the Finnish sample, individuals with this high risk combination were 13x more likely to have a history of violent behaviour.
What did the diathesis-stress model say?
It says we have a genetic predisposition for criminal behaviour which is only expressed after an environmental trigger, such as being raised in a dysfunctional environment.
What research did Raine conduct?
She looked at the brain of people with APD and found reduced activity in the prefrontal cortex, the part of the brain regulating emotion. Furthermore, there was a 11% reduction in grey matter.
What did research into mirror neurons find?
Keysers found that only when asked to empathise could criminals activate their empathy reaction. This suggests that they have empathy but may have a switch to turn on and off.
What is the strength of genetic and neural explanations?
There is support for the diathesis model as Mednick found when neither adoptees biological or adoptive parents had criminal records, only 13.5% had offended but when a biological parent had it rose to 20% and when both biological and adoptive parents had it rose to 24.5%.
What are the weaknesses of genetic and neural explanations?
There are issues with twin studies as it is a small sample of unusual people and there are confounding variables such as the shared environment which may explain concordance rates.
There are problems with adoption studies as they may have stayed with biological parents for a long time or have maintained contact, which means these environmental factors influence them.
It could be accused of reductionism as other factors may have had an influence and be difficult to separate from genetics and neurological explanations.
This is biological determinism and so there are legal issues in court if we say we have no free will.
