biological approach - research Flashcards
what is the context for Raine, Buchsbaum and Lacasse’s 1997 research?
- theories suggested there might be a physical difference between criminals and non-criminals
- Lombroso said that criminals have narrow, sloping foreheads, prominent eye ridges, large ears and protruding chins
what was the aim of Raine et al’s 1997 research?
to identify brain regions specific to offenders charged with murder or manslaughter, who had pleaded not guilty by reason of insanity
what was the methodology of this research?
- quasi experiment (IV not directly manipulated, naturally occurring/ already exists)
- matched pair design
- IV is not guilty by reason of insanity (NGRI)
- DV is brain difference
what was the experimental group of this research?
- 41 murderers (39 men + 2 women)
- mean age of 34.3
- all had been charged with manslaughter and
pleaded NGRI or incompetent to stand trial - all referred to University of California to get proof of their diminished capacity
- were all directed to be medication-free for 2 weeks before the scan
what were the results of the mental capacities of the murderers?
- 6 had schizophrenia
- 23 had a head injury or brain damage
- 3 had a history of psychoactive drug abuse
- 2 had an effective disorder
- 2 had epilepsy
- 3 had hyperactivity or a learning disability
- 2 had a personality disorder
what was the control group of this research?
formed by matching each murderer with a normal individual of the same sex and gender
- the 6 schizophrenics were matched with 6 schizophrenics from a mental hospital
- the other controls had no history of psychiatric illness
- none were taking medication
what was the procedure of this research?
- 10 minutes before the FDG tracer injection, participants were given practice trials on a continuous performance task (CPT)
- 30 seconds before the injection, the task was started so that the initial task novelty would not affect the results of the PET scans
- the FDG tracer was injected. the FDG was taken up by the brain for a 32 minute period during which the participant completed a CPT
- the participant then had the PET scan where the brain was scanned for in 10 mm horizontal slices
what was the first finding of the research?
- NGRI murderers had reduced brain activity in areas previously linked with violence such as the :
- corpus collosum
- left angular gyrus
- pre-frontal cortex
what was the second finding of the research?
- NGRI murderers showed an abnormal asymmetry of activity (reduced activity in left hemisphere and increased in the right) in:
- the hippocampus
- the amygdala
- the thalamus
what was the third finding of the research?
- no differences were found between the NGRI murderers and the control group in the :
- caudate
- putamen
which are associated with mental illness but not violence
what were the other findings of the research?
there were no differences :
- in the performance on the CPT between murderers and the control group, which means any differences were not related to task performance
- between the 14 non-white murderers and the white murderers in the brain activity
- between murderers with a head injury and those without
what were the conclusions of this research?
- overall, the findings support pre-existing biological theories of violence
- the areas of the brain where abnormalities have been found in the murderers may be used to explain their violent behaviour
- however, neural processes regarding violence are complex and can’t be reduced to a single brain mechanism
- instead, there’s disruption between interacting
mechanisms and wouldn’t cause violent
behaviour but would predispose an individual to
violent behaviour
- instead, there’s disruption between interacting
what are the other conclusions of this research?
- the findings can’t say that violence is determined by biology alone; social, psychological, cultural and situational factors also predispose violence
- the research doesn’t demonstrate that NGRI murderers are not responsible for their actions, or that PET scans can be used as a diagnostic technique
- it can’t be ruled out that head injury and IQ may be factors that contribute to the results
- cause and effect is also an issue, all we know is that brain dysfunction is related to violence
- it may be a violent lifestyle that causes changes
in the brain rather than the other way around
- it may be a violent lifestyle that causes changes
what is the evaluation of the methodology?
quasi experiment :
- casual relationships can’t be established as the IV hasn’t been directly manipulated
- there’s a danger that the findings could be misinterpreted and assumed that criminal behaviour is predetermined and inescapable
what is the evaluation of the research technique?
data was collected using PET scans :
- allows researchers to study the brain in detail in ways that were not previously possible
- in the past, researchers relied on post mortem
examinations
- PET scans also allow the brain to be studied in action
- this means it’s highly scientific
