1. Neural explanation

2. How does the MAOA gene link to aggressive behaviour?
The gene determines the production of the enzyme MAOA
MAOA metabolises (‘mops up’) neurotransmitters (e.g. serotonin, dopamine) in the brain after a nerve impulse, it breaks them down to be recycled or excreted.
A dysfunction in the operation of this gene may lead to abnormal activity of the MAOA enzyme, which in turn affects levels of neurotransmitters in the brain.
People with the low-activity form (MAOA-L) produce less of the enzyme and this is correlated with aggression.
MAOA enzyme removes the in from the Amines so they no longer fit in to the receptor on the post synaptic neuron. There is less neurotransmitters to inhibit aggressive behaviour

3. Research showing a link between aggression and the MAOA gene
Han Brunner et al (1993) studied males from a large Dutch family who were repeatedly involved in impulsively aggressive violent criminal behaviour.
It was found that these men had abnormally low levels of MAOA in their brains and the low-activity version of the MAOA gene. This research supports the role of MAOA in aggression as when this gene is not functioning correctly, individuals display aggressive behaviour.

4. This shows the importance of the gene – environment interaction
Caspi et al (2002) studied 500 male children and found those with the MAOA-L gene were more likely to engage in anti-social behaviour as adults but only if they had been maltreated as children

5. The MAOA gene and the environment
Genes are crucial influences on aggressive behaviour, but they do not function in isolation. It appears to be the case that MAOA-L is only related to adult aggression when combined with early traumatic life events.
This indicates that an interaction of genetics and environment is at work in determining human aggression and there the phenotype differs from the genotype.
Possessing MAOA-L does not automatically make you aggressive.

6. Complete the blank spaces to finish off the evaluation paragraphs
Evaluation: page 34-35
Complete the blank spaces to finish off the evaluation paragraphs

7. The genetic approach can be seen to be biologically reductionist
The genetic approach can be seen to be biologically reductionist. Two genes have been linked to antisocial behaviour – CDH13 and MAOA gene. Research conducted by Brunner’s found that the MAOA gene was linked to problem behaviour including impulsive aggression, arson and rape. However, although it is worthwhile to look for biological contributions to criminality and how they impact on an individuals behaviour, it is vital that environmental influences are considered as well. Caspi et al showed that of those with genetic and environmental indicators, 85% developed some form of antisocial behaviour. This highlights that genes and environmental interactions affect behaviour. Further evidence to support this interaction comes from research into epigenetics which shows us that nurture can influence not only behaviour and health in later life, but in subsequent generations. Therefore to be reductionist does not give us a true understanding of what causes antisocial behaviour - a gene variant that is present in a substantial proportion of the population doesn’t have strong explanatory power on its own. Research will need to continue to explore the interaction between specific gene variants and environmental factors that affect criminal behaviour.

8. Biological explanations
As you watch the video, answer the following questions on your handout

9. Read the article
Note down what it states about the amygdala and limbic system and add to your pack

10. Describe the functions of the following areas/neurotransmitters:
Brain physiology: Limbic system/way the brain develops
Frontal lobe
Limbic system
Amygdala
Hippocampus
Thalamus
Seretonin
Dopamine.

11. Describe the functions of the following areas/neurotransmitters:
Frontal lobe: controls actions and feelings (emotions). It is part of the reasoning and higher cognitive functions, and stores long-term memories not associated with learned actions
Limbic system: emotions, memories and arousal
Amygdala: emotional learning and social learning (ability to feel fear and pleasure)
Hippocampus: regulates emotions. The hippocampus is associated mainly with memory, in particular long- term memory
Thalamus: regulate the body's voluntary motor control, consciousness and its sleep/wake cycle. It also regulates the senses of sight, sound, taste, touch and the sense of where the person's body is in space
Seretonin: sleep, temperature regulation, sexual behaviour, appetite, learning, memory, endocrinal functions, anxiety, depression, moods
Dopamine: reward, attention, short-term memory tasks, planning, and motivation.

12. Problems processing emotions could lead to a lack of guilt/remorse
The amygdala is an almond shaped structure in the limbic system. This is area is important for generating emotions, particularly fear.
It has been found that there are important differences in the activity in the left and right amygdala
(reduced activity on the left and increased activity on the right)
Fault in limbic system could lead to a lack of emotional reactions

14. Task
Read Raine’s study and add the main points to the neural explanation sheet. Consider the following evaluation points and add to your handout. Psychology as a science Generalisability Predictive Validity Internal Validity

15. Raine investigated whether the brains of murderers were different from non-murderers.
A sample of 41 violent murderers NGRI
Used PET scans
The IV was whether the participants was a ‘normal’ non-murderer or a murderer who had plead ‘not guilty by reason of insanity’.
The DV was whether the participant showed evidence of brain dysfunction in their prefrontal cortex and other areas such as the angular gyrus, amygdala, hippocampus, thalamus and corpus callosum.
The study used a matched participants design. Participants were matched on age and gender and the six schizophrenics in the experimental group were matched with six schizophrenic controls (‘normal’, non-murderers) who had not committed murder.
Summary of Murderers results
Reduced activity (i.e. reduced glucose metabolism) in some areas, notably the areas previously linked to violence (e.g. the prefrontal cortex, left angular gyrus and corpus callosum).
Abnormal asymmetries: reduced activity on the left, greater activity on the right. This applied to some of the areas identified in the hypothesis as being linked to violence (e.g. the amygdala, thalamus and hippocampus).
No differences in some areas, notably those structures that were associated with mental illness but not violence (e.g. the caudate, putamen, midbrain and cerebellum).
Neural Explanations

16. Raine et al. (1997) Evaluation
+ Ethics – The participants participated under protocols and consent forms approved by the Human Subjects Committee of University of California, Irvine, meaning that participants were protected from harm and gave informed consent.
+ Internal Validity – the use of a matched control group increases the internal validity of Raine et al. (1997).
– Generalisability – the participants were all from California which means it may be difficult to generalise the results to the wider population and murderers who have plead not guilty by reason of insanity in different geographic areas because there may be something specific about Californians which caused the results.
+ Predictive Validity – the statistical significance of the results and the high number of controls use in this study suggests that the results may be used to predict individuals which may be predisposed to commit murder and then plead not guilty by reason of insanity.
+ Psychology as a science – Raine et al. (1997) provides support for the debate psychology as a science. This is because it is a highly controlled, nomothetic laboratory study, which has falsifiable measures.
– Socially Sensitive Research – because this study by Raine, has used Murderers who have plead not guilty by reason of insanity, this study may be considered socially sensitive.

17. Neurotransmitters and criminal behaviour.
Dopamine has been linked to aggression, addiction and substance abuse. It therefore, has a link to criminal behaviour.
Serotonin has been linked to aggression, mood and anti social behaviour. It has been found that low levels of serotonin is linked to higher levels of aggression and anti social behaviour.

18. Individually come up with an excellent – Level 4 evaluation point of biological explanations
Biological determinism
Strengths and weaknesses of research (method)
Nature vs. nurture

19. Interactionist approach to offender behaviour
POINT: If genetics or brain structure do have some influence on offending, it seems likely that this is at least partly comes about through the combination of genetic predisposition and an environmental or psychological trigger. EXPLAIN: For example being raised in a dysfunctional environment or having criminal role models could be the trigger for the individual committing crime. EVIDENCE This idea is illustrated in the low concordance rates in genetic studies suggesting that genes play a minimal part in the development of that particular characteristic, e.g. criminal behaviour. Low concordance rates suggest environmental factors may be responsible or at least partly responsible for criminal behaviour. LINK: The diathesis-stress model could be used to explain criminal behaviour where concordance rates for MZ twins are not 100%; genes create a vulnerability or predisposition towards criminal behaviour combined with stressors and experiences in the environment acting as a trigger for criminal behaviour.

20. Biological reductionism
One criticism of neural explanations of offending behaviour is that they can be considered reductionist. For example, where researchers look at the way a neurotransmitter or brain region might contribute to offending behaviour, they are overlooking other important factors, such as how the environment might have an impact on these areas as well. That being said, such researchers will argue that to be reductionist allows a more straightforward investigation to be conducted as it would be nearly impossible to disentangle all of the possible explanations and their interactions and investigate them scientifically. This is important to consider as while reducing complex behaviour to its simplest form does require researchers to overlook key factors, it is also essential for good scientific practice.

21. Discuss biological explanations of offending behaviour (16 MARKS)
EXAM FOCUS
Discuss biological explanations of offending behaviour (16 MARKS)

22. Genetic explanations, focusing on ‘criminal’ genes such as the MAOA gene (which controls levels of brain serotonin) linked to criminal aggression
Brain pathology explanations, possibly liked to genes and/or early abuse; examples include the relationship between psychopathy and abnormalities of frontal lobe and amygdala function

23. Evidence from MZ/DZ twin studies and family studies looking at genetic factors
•        Findings support a genetic involvement in criminal behaviour but concordance rates in MZ twins are not high and leave plenty of room for non- genetic environmental factors
•        Brain scanning studies that show pathology in brains of criminal psychopaths, but cannot conclude whether these abnormalities are genetic or signs of early abuse
•        Some evidence from genome-wide association studies for particular genetic factors linked to criminal psychopathy, but little replication
•        Counter-evidence for environmental factors in offending behaviour; socio- economic status, social learning theory
•        General nature of ‘offending behaviour’ – some specific forms may be more ‘biological’ than others eg physical aggression

24. Further reading
ow-to-spot-a-murderers-brain