Topic 1 - What makes a criminal?

Outline Dabbs background research

• Looked at the link between testosterone and aggressive, violent behaviour

• Females have about the tenth of the testosterone of males and they only account for 3.8% of people in prison in the UK and a fraction of the violent crime rate- this offers a biological explanation for behaviour

• Dabbs studied testosterone, crime and misbehaviour among 692 male criminals who had committed personal crimes of sex and violence

• Testosterone was measured in saliva samples

• Inmates with higher testosterone also violated more rules in prison, especially those involving overt confrontation

What are the strengths of Dabbs research?

• High population validity- 692 male prisoners

• Saliva samples- objective measures

  • Increased validity

What are the weaknesses of Dabb’s research?

• Androcentric

  • But the prison population is 96% male so this may be justified

• Reductionist- only looking at testisterone

Outline Gesch’s research

• There is evidence that diets lacking in essential nutrients can adversely affect behaviour

• Omega 3 is essentially for synapse development

  • Aa lack of thise can reduce cognitive function and can lead to aggression and failure to consider the consequences for one’s actions

• Gesch used a double blind, placebo controlled and randomised trial of nutritional supplements on 231 young adult prisoners

• After taking supplements, there was found to be a 35% reduction in offences compared to before supplementation

• Conclusion- antisocial behaviour such as violence in prisons are reduced by vitamins, minerals and essential fatty acids

What are the strengths of Gesch’s research?

• Large sample- 231 young adult offenders

• Double blind- reduces researcher bias

• Before and during supplementation- comparisons made which increases cause and effect

• Taking capsule- less criminality (useful)

What are the weaknesses of Gesch’s research?

• Quantitative data- lacks insight

• Reductionist- suggests only Omega 3 is affecting violent behaviour

Outline Farrington and West’s research

• Social explanations for criminality include upbringing and risk factors that children are exposed to in their environment

• Large scale study of 411 boys at Cambridge who were 8 when the study began

• The study interviewed them as adolescents and again as adults

• Their juvenile and adult criminal records were reported

• Risk factors identified included:

  • Poor school performance- feeling belittled by teachers or peers, feeling of having no future

  • Poorer and larger families- Squalid conditions encourage crime like stealing

  • Family criminality- SLT

What are the strengths of Farrington and West’s research?

• Large sample- 411 boys

• Longitudinal

• Interviews- gains insight, increases validity, qualitative data

• Range of risk factors- holistic, insight

What are the weaknesses of Farrington and West’s research?

• Androcentric

• Ethnocentrism- Cambridge

• Interviews could lead to social desirability bias

What is the aim of Raine’s research?

To discover if murderers who plead not guilty by reason of insanity show evidence of brain abnormality

What is the background of Raine’s research?

• PET scans

• Glucose radioactively tagged with fluorine measured the amount of brain activity using the metabolic rate as a measure

• More colour indicates brain activity

What is the method and design of Raine’s research?

• Quasi experiment

• Matched pairs- age, gender and diagnosis of SZ

What are the variables for this study?

• IV- NGRI murderer vs ‘normal’ non-murderers

• DV- Whether p’s showed evidence of brain dysfunction in pre-frontal cortex/corpus callosum

What is the sample for Raine’s research?

• 41 participants in total

• 39 men, 2 women

• 6 had schizophrenia, 23 had head injuries

• University of California

• Mean age- 34.3

• All had been charged with murder or manslaughter and had been referred to find out if they were NGRI

What is the procedure for Raine’s study?

• Offenders in custody for 2 weeks, kept medication free before scanning ​

• None of the controls were taking medication either​

• Pp given practice trials (10 mins before real thing) on a Continuous Performance Task (CPT) – a concentration task which activates the PFC in the brain​

• Started the real CPT​ 30 seconds before the injection of FDG

• They were given a fluorodeoxyglucose (FDG) injection –traces glucose metabolism in brain​

• PET scans show where in the brain glucose is being used which indicates activity in areas of the brain​

• 32 mins later – pps went to adjacent PET scanner where brain was scanned 10times at 10mm intervals to measure activity in different regions of the brain​

How do the prefrontal cortex and the corpus callosum mediate aggressive behaviour?

• PFC- planning, impulse control, understanding consequences, in healthy brains this region inhibits aggressive behaviour

• Corpus Callosum- Nerve fibre connecting the left and right hemispheres

  • Healthy brains allows the left hemisphere to moderate emotional impulses for the right hemisphere

What results can be found from Raine’s study?

• PFC- lower activity in controls

  • Linked to loss of self- control and altered emotion

• Corpus Callosum- lower activity than controls

  • May stop left brain inhibiting the right’s violence

What conclusions can be made from this study?

• Murderers pleading NGRI have sig differences in the metabolism of glucose in anumber of brain areas compared to non-murderers ​

• Reduced activity in PF areas may explain impulsive behaviours, loss of self-control,evidence of immaturity, altered emotionality and inability to modify behaviour –combinations of all of these may make it easier to carry out different kinds ofaggressive acts as the normal constraints on behaviour may be reduced ​

• Violent behaviour cannot be reduced to one single brain mechanism – there are several processes involved…if there are deficits in a number of these processes, the likelihood of violent behaviour increases​

• Results do not show that violent behaviour is determined solely by biology – many factors must be considered – social experiences, situational factors, learned behaviour​

How can we apply using anti-androgens like Triptorelin to reduce violent sexual behaviour and what research can be used to support this?

• Anti-androgens like triptorelin act to reduce testosterone levels, therefore reducing sex drive​- chemical castration

• This therefore reduces the chance of reoffending

• Supported by Dabbs’ research- sex offenders have higher levels of testosterone than offenders who had committed property offences

Note that this can ONLY be used when talking about sexual offences

How can we apply nutritional supplements to reducing criminality and what background research can we use to support this?

• Gesch- decreased omega 3 levels leads to decreased cognitive function

• Could lead to aggression and failure to consider consequences

• 35% reduction is offences when taking nutritional supplements with Omega 3 after a minimum of 2 weeks