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Answer the following exam question: Discuss the role of profiling in forensic psychology (16 marks)
(20 minutes)
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Biopsychology question
Outline the divisions of the nervous system (6)
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Outline the division of the nervous system (6)
The nervous system is split into the central nervous system (CNS) and the peripheral nervous system (PNS). The central nervous system is divided into the brain, which contains billions of nerve cells and the spinal cord which links the brain to the peripheral nervous system. The PNS is split into the somatic nervous system (SNS) and the autonomic nervous system (ANS). The somatic nervous system consists of sensory neurons which transmit information from the sensory receptors in the body to the CNS. Motor neurons transmit information from the CNS to voluntary muscles for movement. The ANS works automatically and is not under voluntary control. It is split into the sympathetic nervous system, which is responsible for the fight or flight response and the parasympathetic nervous system which returns our body back to calm after the stress response, otherwise known as rest and digest.
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Objectives To be able to describe and evaluate genetic explanations for criminal behaviour. To be able to describe and evaluate neural explanations for criminal behaviour. To be able to evaluate biological explanations for criminal behaviour.
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http://www. independent. co
The Mobley Defence Real world application/issues and debates Stephen Mobley ( ) was a convicted murderer executed by the State of Georgia for the 1991 killing of John C. Collins, a 25- year-old college student working nights as a Domino's pizza store manager. On appeal, Mobley's attorneys advanced a novel argument that Mobley was genetically predisposed to seeking violent solutions to conflict. The case was described as "perhaps the most widely cited case in which defence lawyers used genetic factors in the defence of their client". Genetic determinism. Are we born to kill?
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Genetic and Neural Explanations of offender behaviour
Aim: to examine and evaluate the genetic and neural explanations for crime.
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Genetics and neural explanations
Genetics: Genes consist of DNA strands. DNA produces ‘instructions’ for general physical features of an organism (e.g. eye colour, height) and also specific physical features (such as neurotransmitter levels and size of brain structures). These may impact psychological features (such as intelligence and mental disorder). Genes are transmitted from parents to offspring , i.e. inherited. Who do we study to look at the effects of genes on behaviour? Neural explanations: Any explanation of behavior (and its disorders) in terms of (dys)functions of the brain and nervous system. This includes the activity of brain structures such as the hypothalamus, and neurotransmitters such as serotonin and dopamine
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Twin studies recap 2 advantages of studying twins as a psychologist
2 disadvantages of studying twins as a psychologist
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Twin studies: main issue
Twin studies can only indicate a possible genetic component to a trait. They cannot find the genes involved, nor can they say much about the mechanisms by which environment or upbringing could overcome the genetic predisposition
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Research: twin studies
Christiansen (1977) examined over 3,500 twin pairs in Denmark and identified concordance rates of criminal behaviour as follows: What do these findings suggest?
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Monoamine oxidase is an enzyme involved in the deactivation of certain neurotransmitters such as serotonin (mood, emotion, sleep), dopamine (transmits signals within the brain to produce smooth physical movements) and norepinephrine (body response to stress) Defects in the gene Monoamine oxidase A (MAOA) prevent the enzyme from working, so causing a build-up of neurotransmitters in the brain, perhaps resulting in over-excitation of the nerves in stressful situations. It has been found than in some violent males they have this variant of the gene. Signals transmitted by serotonin regulate mood, emotion, sleep, and appetite. Epinephrine and norepinephrine control the body's response to stress. Dopamine transmits signals within the brain to produce smooth physical movements
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MAOA has been used extensively to treat patients with depression, with no apparent increase in violent tendencies. Furthermore, one of the neurotransmitters building up in the men was serotonin, which other researchers have found to depress, rather than increase, the propensity for aggression.
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Add to your handout Fergusson et al Background
A 30-year longitudinal study. Aims To test the hypothesis that the presence of the low-activity MAOA genotype was associated with an increased response to abuse exposure. Method Participants were 398 Results The analyses revealed consistent evidence of G × E interactions, with those having the low-activity MAOA variant and who were exposed to abuse in childhood being significantly more likely to report later offending, conduct problems and hostility. Conclusions The present findings add to the evidence suggesting that there is a stable G × E interaction involving MAOA, abuse exposure and antisocial behaviour across the life course.
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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 Add to your handout
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Task: Mind map the research: Farrington for family studies (hand out)
Christiansen for twins Crowe adoption study. Read Brunner (1993) study in your pack. What does it show? Add to your hand out The study by Brunner shows that a variant of the MAOA gene is seen in violent males, as seen in the research. However, it is important to understand that there may be important environmental factors that contribute the development of criminal acts. Maybe the MAOA gene is only half the story? In Denmark every pair of twins born since 1870 has been registered with the authorities, as has every criminal.
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Nature or Nurture? Interesting
8.5% of the US population report having suffered from a head injury. 60% of inmates in US prisons report having suffered a head injury. Nature or Nurture?
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Create a PEEL evaluation point
Biological determinism presents problems for our legal system since it negates free will and raises the ethical question surrounding what society does with people who carry criminal genes A focus on the nature of criminal behaviour but not considering the nurture of criminal behaviour. Time of adoption: Many adoptees are adopted late so spend their infancy with their biological parents anyway. Some also maintain regular contact with their biological parents. This means that the parents may have had an environmental rather than biological impact. Early twin studies are often unreliable since zygosity (whether twins are MZ or DZ) was based on appearance rather than DNA testing. Therefore they may lack validity. Problems with twin studies Twin studied involve small sample sizes and the fact that most twins are raised in the same environment is a confounding variable as concordance rates may be due to shared experiences (SLT ) rather than genetics Biological reductionism is an issue within these studies as criminality is complex and environmental factors must be considered.
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Neural explanation
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The amygdala is an almond shaped structure in the limbic system
The amygdala is an almond shaped structure in the limbic system. This is area is important for the processing of emotions, particularly fear. It has been found that there are important differences in the activity in the left and right amygdala
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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
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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.
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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. Raleigh et al (1991) studied Vervet monkeys fed on diets rich in tryptophan (an amino acid needed to make serotonin) they found they had decreased levels of aggression compared to monkeys fed on a diet low in tryptophan. Although this is looking at aggression rather than criminal behaviour it can link to violent criminal behaviour.
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Evaluation (page 31) The you should evaluate the area as a whole:
Scientific methodology Natural/quasi experiments Why is the damage present? Could it be due to abuse, diet, lack of stimulation, shaken baby syndrome? Are the neurotransmitter imbalances a cause or effect? Correlational research.
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Lets come up with an excellent – Level 4 evaluation point of biological explanations
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