Criminal behavior Biological exp 1 Flashcards
Genetic evidence for inherited criminality?
The genetic theory proposes that multiple genes predisposes people to criminal behavior.
The evidence comes from twin studies where identical and non identical twins are compared.
Studies for genetic factors of inherited criminality?
Adrian Rain (1993) reviewed research on delinquent behavior and found a 52% concordance rate for MZ twins and only a 21% concordance rate for DZ twins.
Searching for genes linked to inherited criminality?
The genes monoamine oxidase A (MAOA) and Cadherin 13 (CDH13) have both been linked to criminal behavior.
Evidence of MAOA link to criminal behavior?
Han Brunner et al (1993) studied 28 male members dutch family with a history of impulsive violent crime. They found they had low levels of MAOA (warrior gene).
Evidence of MAOA and CDH13 link to criminal behavior?
Jari Tiihonen et al (2015) studied 900 offenders and found low levels of MAOA and CDH13.
Diathesis-stress model?
It is believed that genes are not responsible for stress alone. It is thought that epigenetics are responsible. They are turned on and off by epigenomes which are effected by environmental factors. Maltreatment in childhood is an environmental cause.
Evidence for diathesis-stress model?
Avshalom Caspi et al (2002) used data from longitudinal Dunedin study which followed 1,000 babies in 1970s. They found 12% of men with low MAOA gene had experienced maltreatment but they were responsible for 44% of violent convictions.
Difference in brain structure?
Genes in criminals may effect brain structure. Raine (2004) studied 71 brain scans where of murderers. He found they had reduced functioning in the pre-frontal cortex (this is involved in regulating emotions).
Seo (2008) identified low levels of serotonin could predisposes people to criminal behavior.
Wright (2015) identified that high/low levels of nor adrenaline can cause aggression.
Supportive research from adoption studies?
Crowe (1972) found that adopted children with criminal biological parents were 38% more likely to get a criminal record by 18. Those with out parents with a criminal record only had a 6% chance of getting a criminal record by 18.
Mednick (1987) studied 14,000 adopted people. Boys adopted into a criminal family had a 15% chance of getting a criminal record compared with 20% getting a criminal record if they had biological parents with a criminal record.
Explaining non violent crime?
Most research into criminal behaviour is focused on violent crime and cannot be generalised to other types of crime.
Findley (2011) suggested that crime is not a natural category and is made up of a social construct.
Problems with determinism as an explanation?
You are born with your genetics and they decide your behaviour. This was the argument used by Staphan Mobley’s lawyers to excuse his crime (murder).
Tiihonen et al (2015) says those with defective genes are 13 times more likely to repeat violent behaviour. However, not everyone with defective genes commits violent behaviour. This means there are other factors aside from genetics.
Brain difference - cause or effect?
For genes to cause criminal behaviour it has to be linked to a psychological or physical effect.
Many criminal report having a head injury. Harmon (2012) identified that only 8.5% of the United states population have had a head injury. However 60% of United States prison population have had a head injury.
