Criminal Behaviour - Biological Explanation Flashcards
What are the Biological Explanations of Criminal Behaviour?
- Inherited Criminality
2. Role of the Amygdala
What are the Factors in Inheriting Criminality?
- Genes predispose individuals to criminal behaviour
- MZ = monozygotic - identical
- DZ = dizygotic - fraternal
- Evidence for gentetic component comes from twin studies
- Raine (1993) = Reviewed research om delinquent behaviour - found 52% concordance for MZ compared with 21% concordance for DZ
What are the Genes Linked to Criminal Behaviour?
Research
- Monoamine Oxidase A (MAOA)
- Cadherin 13 (CDH13)
Brunner (1993) = analysed DNA of 28 males of a Dutch family with histories of impulsive + violent crimes (e.g. rape/attempted murder) - found all men shared abnormally low levels of MAOA
Tiihonen (2015) = 900 offenders found evidence of low MAOA activity + low CDH13 activity - estimated that 5-10% of all violent crimes was due to abnormalities of these genes
Explain the Link Between MAOA Gene and Aggression.
Defective MAOA GENE
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Deficiency in MAOA Enzyme
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Neurotransmitters Neurodenaline builds up
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Person responds aggressively in stressful situations
What is the Diathesis-Stress Model?
- Epigentics (heritable changes in gene expression) propose an interplay where genes are switched on/off by epigenetics which has been affect by environmental factors - A Diathesis-Stressor
- Maltreatment in childhood may play a factor
Caspi (2002) = data used from longitudinal study of 1000 people who were born in the 1970s -addressed antisocial behaviour at 26 - found 12% men were low MAOA had experienced maltreatment - were responsible for 44% of violent crimes
How Does Differences in Brain Affect Inheritableity of Criminality?
- Criminal gene may cause difference in areas of brain/differences in key neurotransmitters
- Raine (2004) = 71 brain imaging (murders/psychopaths/violent/individuals) - all had reduced functioning in prefrontal cortex (area involved in regulating emotions/controlling behaviour/moral behaviour) - lowered activity in this area is associated with impulsiveness/loss of control
- Seo (2008) = suggest that low levels of serotonin predisposes individuals to impulsive aggression + criminal behaviour - Serotonin inhibits prefrontal cortex - dopamine hyperactivity may enhance this effect
- Very high/low levels of nurodenaline associated with aggression/criminality - norodenaline helps people react to perceived threats - low levels = reduced activity
Inherited Criminality Evaluation
Research Support From Adoption Studies
POSITIVE
- Crowe (1972) = adopted children whose biological parent was a criminal had a 38% greater risk of having a criminal record by the age of 18
- Mednick (1987) = 14000 adoptees found 15% sons adopted to criminal families went on to be criminals compare to 20% whose biological parents were criminals - suggesting that inherited genes are a more significant factor
Inherited Criminality Evaluation
Explaining Non-Violent Crimes
NEGATIVE
- Most genetic research on criminal behaviour relates to violent crimes - genes can only account for crimes involving violence/psychopathy
- theft/fraud/drug use are not violent
- Blonigen (2005) - found support for a genetic basis looking over 600 twins
- Findley (2011) = crime not a natural category but a social construction
- Difficult to argue that criminal behaviour can be explained in terms of genetic + its interaction with the environment
Inherited Criminality Evaluation
Problems with Deterministic Explanations
NEGATIVE
- Tihonen (2015) = those with defective gene were X13 more likely to have a history of repeated violent behaviours - not everyone with gene had/will become a criminal
- Is the causation of a person’s behaviour out of their control? it may be harder for some individuals to avoid criminal violence due to biological + environmental factors - deterministic view can be ruled out
Inherited Criminality Evaluation
Brain Difference: Cause OR Effect?
A POINT TO CONSIDER
- Linked to a physical/psychological effect
- Common observation = criminals report head injury - 8.5% US population compared with 60% of US criminals
- Brain differences may be due to nurture rather than nature
Applying Inherited Criminality to Modifying Criminal Behaviour - Genetic Engineering
- Removing the genes from the gene pool (e.g. not having kids)
- Genetic Engineering - individuals genetic composition is altered so that undesirable traits are eradicated
- Example = replace defective MAOA gene with a normal one in a fertilised egg
- Removing undesirable genes/traits from population has not been successful - eugenic movement in early 20th century advocated sterilisation
- Now seen as very unethical - Nazis supported the idea
What is the Structure of the Amygdala?
- Structure in the brain makeup of grey matter - collection of neurons densely packed together into a of 13 nuclei
- Located in the medial temporal lobe - part of the limbic system
- 2 amygdalae, 1 per hemisphere
- Neurally linked to the hypothalamus, the hippocampus + prefrontal cortex
What is the Function of the Amygdala?
- First implicated in emotional behaviour by Papez (1937) + then Maclean (1952)
- Has a wide spread influence on brain functioning + behaviour associated with emotion/motivation/social interaction
- Big role in how we assess + respond to environmental threats - importance in determining aggressive behaviour
Describe the Link Between the Amygdala + Aggression.
- Coccaro (2007) - investigated effects of amygdala on aggression by studying people with intermittent explosive disorder (IED) - each participant viewed images of faces at the same time as having a FMRI - Key difference = IED showed higher levels of amygdala activity - demonstrates an association between amygdala activity + processing
What is the Link Between Amygdala + Fear Conditioning?
- Gao (2010) = as children we learn to inhibit our aggression/antisocial behaviours through fear conditioning - aggression = punishment
- Amygdala involved in processing fear information + fear conditioning
- A dysfunctional amygdala means that the child cannot identify social cues that indicate threat - child does not link punishment to aggressive behaviour
- Longitudinal study of 1795 people - tested for fear conditioning - used physiological arousal is response to painful norse - 20 years later those who had committed crimes had showed no fear response at the age of 3.
