Biological Approach Flashcards
Describe the Biological Assumption of ‘Evolutionary Influences’
Evolutionary psychologists explain human behaviour based on Charles Darwin’s Theory of Evolution. This
theory states that species survive through natural selection; a process where those who are better suited to their environment tend to survive and therefore produce offspring.
The more evolved a person’s brain is, the more likely they are to survive in their ever-changing environment.
The genes that allow these individuals to be successful
are then passed to their offspring who will, in turn, also be
more successful. This means that genes within evolved families are more likely to be passed to each new generation. This is called ‘survival of the fittest’.
Describe the Biological Assumption of ‘Localisation of Brain Functions.’
The cerebral cortex can be divided into four sections, which are known as lobes:
1. Frontal lobe: located at the front of the brain, responsible for problem solving.
2. Parietal lobe: located in the middle section of the brain, responsible for sensory processes such as pain.
3. Occipital lobe: located at the back of the brain, responsible for interpreting visual stimuli.
4. Temporal lobe: located on the bottom section of the brain, responsible for interpreting auditory stimuli.
Describe the Biological Assumption of ‘Neurotransmitters’
Apply the assumptions of the Biological approach to explain two human behaviours.
note: ocd - impulses
Describe the Methodology of ‘Raine et al’s Study: Abnormalities in murderers.’
Raine et al.’s study was a quasi-experiment (meaning that the independent variable, murderers who pleaded ‘NGRI’, had occurred naturally) which used a matched-pairs experimental design. The dependant variable of this research was the brain abnormalities/differences between the murderous individuals and the non-murderous, matched participant.
The participants of this study were separated into two groups: the ‘experimental group’ and the ‘control group.’
The experimental group - or, the ‘murderers’ - consisted of 41 individuals (39 men, 2 women) with a mean age of 34 yrs old. They had all been charged with murder and had all pleaded ‘not guilty, due to reason of insanity’ (NGRI). The participants were referred to the University of California for examination to obtain proof of their diminished capacity. Each of the murderers were proven to have some form of mental illness: 6 were diagnosed with schizophrenia, 2 with affective disorders, 2 with epilepsy, and 2 were diagnosed with a personality disorder. Other mental impairments recorded consisted of: 3 having a history of learning disability, 23 having had a history of traumatic brain injury and 3 having histories of psychoactive drug abuse. The participants were also required to be off medication/drugs and were tested with a urine scan prior to brain scanning.
The control group was formed by matching each participant of the experimental group with a non-murderous individual of the same sex and age. Additionally, the schizophrenic members of the experimental group were matched with 6 participants who also had diagnoses of schizophrenia, sampled from a psychiatric hospital. However, he other controls had no history of psychiatric illness and no history of physical impairments. None were on medication.
Describe the Procedure of ‘Raine et al’s Study: Abnormalities in murderers.’
The sample was obtained using opportunities sampling. A PET scan was used to study the active brain.
Firstly, all participants were given an injection of a ‘tracer’ known as Fluorodeoxyglucose (or, FDG). This tracer would then be taken up by active areas of the brain therefore allowing researchers to compare the brain activity of the experimental and control group.
Secondly, all participants were asked to do a ‘continuous performance task’ (CPT) aiming to specifically target areas of the brain, meaning that researchers could observe how the brain functioned.
The participants were given a chance to practice the CPT before receiving the FDG injection. Thirty seconds before the FDG injection was administered, the participants started to CPT so the initial task novelty (?) would not be FDG labelled. Ultimately, thirty-two minutes after the FDG injection was administered, a PET scan was done of each participant. Ten horizontal slices (pictures) of their brain were recorded using the cortical peel and box techniques. These findings were then recorded in the official, published article of the study so that it could be easily replicated in potential, future research.
Describe the Findings of ‘Raine et al’s Study: Abnormalities in murderers.’
Brain Differences:
- The study found reduced activity (i.e. reduced glucose metabolism) in the experimental group in areas previously linked to violence: such as, the prefrontal cortex, the left angular gyrus, the corpus callosum and in the left hemisphere amygdala, thalamus and hippocampus.
- The study also found increased activity (i.e. increased glucose metabolism) of the experimental group in areas that had not been previously linked to violence: such as, the Cerebellum and in the right hemisphere amygdala, thalamus and hippocampus.
- Additionally, the study found no difference in activity between the experimental and control group in other areas, not previously linked to violence: such as, the caudate, the putamen, the globus pallidus and the midbrain.
CPT Performance:
Both groups performed similarly in the continuous performance task, meaning that no observed brain differences were related to task performance.
Other Differences:
Some other differences between the experimental and control group were noted:
- Asymmetry: Six of the experimental group were left-handed and showed less amygdala asymmetry and higher medial pre-frontal activity than right-handed people.
- Ethnicity: 14 of the experimental group were people of colour. They showed no significant difference in brain activity compared to white participants.
- Head Injuries: The brain activity of the 23 participants with a history of brain injury did not differ from those with no history.
Describe the Conclusions of ‘Raine et al’s Study: Abnormalities in murderers.’
The findings of this research provide evidence that murderers pleading NGRI have different brain functions to non-murderous individuals. Violent behaviour can be explained through the disruption/dysfunction of brain networks and structures.
Raine stated that the findings of this research cannot be taken to conclude that violence us entirely predetermined by an individuals brain function. However, certain differences may pre-dispose someone towards violent behaviour.
The data do not demonstrate that murderers pleading NGRI are not responsible for their actions, nor do they demonstrate that PET scans can be used as a diagnostic technique.
The findings also cannot be generalised from NGRI cases to other violent offences.
