Forensics: Biological Explanations

Front 1

Twin studies

Back 1

Raine- studied delinquent behaviour in twins and found a 52% concordance in MZ twins compared to 21% in DZ twins

Front 2

Genetics: Monoamine oxidase A (MAOA)

Back 2

Brunner- Dutch family known for impulsive and violent criminal behaviour.
DNA analysis showed abnormally low levels of MAOA

Front 3

Genetics: Cadherin 13 (CDH13)

Back 3

Tiihonen- 900 criminals studied, found low levels of MAOA and CDH13 in nearly all the criminals

Front 4

Neural: Prefrontal cortex

Back 4

Raine- brain scans of 71 murderers/psychopaths/violent individuals. Found they have reduce functioning in this area, causing issues regulating emotions, poor impulse control and impulsiveness

Front 5

Neural: Limbic system

Back 5

Thalamus and amygdala, linked to emotion and motivation.
Raine- studied NGRI murderers and found abnormal asymmetries. Reduce activity on the left but increased on the right side.

Front 6

Neural: serotonin and noradrenaline

Back 6

Low serotonin levels increase impulsive aggression by inhibiting the prefrontal cortex.
High levels of noradrenaline heighten the F or F response and increase reactivity to perceived threats

Front 7

Diathesis-stress model

Back 7

Caspi et al- longitudinal study, 1000 people in NZ born in the 70's. 12% men with MAOA had experienced maltreatment as babies and were responsible for 44% of convictions

Front 8

Mirror Neurons: APD

Back 8

Keysers et al: people with APD can experience empathy, however only when asked to empathise with someone in a movie/film. This suggests people with APD are not void of empathy, but rather are able to turn it on and off, unlike "normal" people.

Front 9

Genetrics: Evaluation of twin studies

Back 9

Cannot be generalised to the wider population as not everyone is a twin and the studies conducted used small sample sizes
MZ twins are brought up similarly due to being identical, therefore environment may have been a confounding variable

Front 10

Adoption studies: support

Back 10

Crowe- adopted children with a biological, criminal, mother were 50% more likely to have a criminal record by 18 than those without a criminal mother

Front 11

Genetics: Adoption studies: issues

Back 11

Many adopted children spend much of their infancy with their biological parents and keep in contact with them, suggesting biology might not have as large of a role.

Front 12

Genetics: Diathesis-stress model: support

Back 12

Mednick- Danish 13,000 adoptees. 13.5% adoptees with no criminal biological or adoptive parents had a criminal record
20% of those with criminal biological parents and 24.5% when both biological and adopted parents were criminals

Front 13

Genetics: evaluation: determinism

Back 13

Explanation only focuses on violent crimes and ignores fraud/drugs etc. Crime and its categories are all social constructions.
By using biology as an explanation, it removes the idea of free will and makes the accused look like a victim.

Front 14

Genetics: Evaluation: reductionism

Back 14

It reduces behaviour to the simplest level of explanation and ignores other factors (other than DSS) such as biology or SLT.
Human behaviour is more complex and other factors always impact on development.

Front 15

Evaluation case study: Mobley

Back 15

Claimed the MAOA gene made him shoot a Dominoes manager in the neck.

Front 16

Neurons: Evaluation: cause or effect?

Back 16

Are abnormal levels of serotonin and noradrenaline caused by criminal behaviour? Or are they the cause of criminality?
Are changes in prefrontal cortex and limbic system activity to blame for criminal behaviours? Or does criminal behaviour alter brain structures?