Biological Explanations Of Offending Behaviour: Genetic And Neural Flashcards
What are genetic explanations
- propose that more than one or more genetics predispose people to criminal behaviour.
Eg: twin studies, where identical and non-identical twins are compared. Raine (1993) found 52% concordance for MZ twins compared to 21% for DZ twins
What’s the link between MAOA and criminals
- research by Brunner, studied 28 males of a Dutch family who had history of impulsive, violent and criminal behaviour. He found they shared a particular gene leading to low levels of MAOA
What’s the link between CDH13 and criminals
Jan Tilhonen et al (2015) studies 900 offenders, found low levels of MAOA and CDH13.
- estimated 5-10% of violent crime in Finland is due to abnormalities in these genes
What is the Diathesis stress
- proposes a gene or a few genes will not determine someone’s behaviour, instead thinking in terms of epigemetics proposed an interplay where genes are switched on and off by epigenomes, which are affected by environmental factors
What study supports the Diathesis-stress
-Caspi et al (2002) used data from longitudinal Dunedin study which followed 1000 people from when they were babies in the 1970s. Caspi assessed anti-social behaviour at age 26, finding 12% of those men with low MAOA genes suffered maltreatment when they were babies but were responsible for 44% of violent convictions
What are neural explanations
Consider how structure of the brain may be different in criminals as well as differences in neurotransmitter levels
What’s the link between head injuries and criminals
- 8.5% of US population have had a brain injury, compared to 60% of people in US prisons (Harmon 2012)
What’s the link between the prefrontal cortex and criminals
- raine (2004) citied 71 brain imaging studies showing murderers, psychopaths and violent individuals had reduced functioning in prefrontal cortex ( involved in regulating emotion and controlling moral behaviour in general)
What’s the link between the limbic system and criminals
- thalamus and amygdala are linked to emotion and motivation.
- raine (1997) studied murderes who were found not guilty by insanity. They found abnormal asymmetries in limbic system, especially the amygdala, reduced activity on left and increased activity on right side of the brain
What’s the link between serotonin and criminals
- seo (2008) suggests low levels may predispose individuals to impulsive, aggressive and criminal behaviour.
- low levels mean a lack of inhibition, by the prefrontal cortex of impulsive aggressive urges.
-dopamine hyperactivity could enhance this effect
What’s the link between noradrenaline and criminals
High and low levels have been associated with criminal behaviour
-wright (2015) found high levels of noradrenaline are associated with activation of sympathetic nervous system and fight or flight response - linked to aggression
- noradrenaline also helps people perceive threats, so low levels would reduce this ability
What research supports findings of twin studies, that there are elements of inheritance in offending behaviour
- Crowe (1972) found adopted children who had a biological parent with a criminal record were 50% more likely to have a criminal record by age 18, whereas adopted children who’s mother didn’t have a record had only a 5% risk.
- suggests inherited genes are more significant then environmental factors
Can genetic and neural explanations explain non-violent crimes
- research into offending behaviour doesn’t focus on non-violent offences like theft, fraud
- therefore it’s hard to explain such a range of behaviours simply in terms of genetics and interaction with their environment
How does deterministic explanations act as a limitation for genetic explanations
- it can be argued a gene someone is born with will determine later behaviour, this is supported by tilhonen et al as those with a defective gene were 13x more likely to have a history of repeated violent behaviour, but not everyone became a criminal.
- therefore a deterministic view of criminal behaviour cannot be totally ruled out
