Biological explanations: genetic and neural. Flashcards
Definition of genetics.
Consist of DNA.
DNA produces ‘instructions’ for general physical features of organism (height) and specific physical features (neurotransmitter levels). Impact psychological features (intelligence, mental disorders).
Genes transmitted through inheritance.
Describe Christiansen’s study on twins and adoption.
Studied 3500 twin pairs, concordance rates for offender behaviour of 35% for identical twin males and 13% for non-identical males.
Offender behaviour checked against Danish police records- data indicates behaviour isn’t just inherited underlying traits.
Describe Crowe’s findings on adopted children.
Adopted kids whose bio mum had criminal record, 50% risk of having criminal record by 18.
Adopted kids who bio mum didn’t have a criminal record had 5% risk.
What did Tiihonen et al find, in terms of 2 genes being associated with violent crime?
Genetic analysis 800 offenders.
MAOA gene regulates serotonin in brain, linked to aggressive behaviour.
CDH13 gene linked to substance abuse and ADHD.
Analysis found 5-10% of all severe violent crime in Finland attributed to MAOA and CDH13 genotypes.
If genetics influence offending, how is it encouraged by effects of the environment? (Diathesis-stress model).
Tendency towards offending behaviour come through combination of genetic predisposition and bio/ psychological trigger.
E.g. raised in dysfunctional environment/ having criminal role models.
Describe a limitation of using twin studies as genetic evidence, in terms of assumptions of equal environments.
Assumed by researchers studying twins that environment factors constant because twins brought up together, experience similar environments.
‘Shared environment assumption’ apply to MZ twins (identical) than DZ (non-identical), because MZ identical- treated similar, affecting behaviour.
Higher concordance rates for MZ’s in twin studies may be because treated similarly than DZ twins.
Describe a strength of the diathesis-stress model of offending, in terms of support.
Mednick- Study of 13,000 Danish adoptees.
Neither bio/ adoptive parents had convictions, percentage adoptees that did 13.5%, rose to 20% when either bio parent had convictions, 24.5% both adoptive and bio parents had convictions.
Shows genetic inheritance and environmental influence involved in offending, supporting diathesis-stress model of crime.
Definition of neural explanations.
Explanation of behaviour in terms of dysfunctions of brain and nervous system.
Indicates activity of brain structures, prefrontal cortex, neurotransmitters (serotonin and Dopamine).
Describe Raine’s studies of APD (Antisocial personality disorder) in the brain?
Reported brain-imaging studies demonstrating individuals with APD, reduced activity in prefrontal cortex (regulates emotional behvaiour).
Found 11% reduction in volume of grey matter in prefrontal cortex of pp with APD compared to controls.
Describe Keyser’s study, in terms of mirror neurons and empathy.
Offenders with APD can experience empathy, not very often.
when offenders asked to empathise their empathy reaction (controlled by mirror neurons in brain) were activated.
Suggests APD individuals aren’t without total empathy but may have a neural switch, turned on and off, unlike ‘normal’ brain which has the empathy switch always on.
Describe a strength of neural explanations, in terms of support for links between crime and frontal lobe.
Kandel and Freed reviewed evidence of frontal lobe damage and antisocial behvaiour.
PP with this damage tend to show impulsive behvaiour, emotional instability and inability to learn from mistakes.
Supports idea brain damage factor in offending behvaiour.
Describe a limitation of neural explanations, in terms of links between neural difference and APD complex.
Farrington- studied group men, scored high on psychopathy (APD).
Individuals experienced risk factors during childhood, raised by convict + physical neglect- cause APD and some neural differences associated with reduced activity in frontal lobe due to trauma- Rauch.
Suggests relationship between neural differences, APD and offending complex, other intervening variables that have an impact.
