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Biological Explanations - Coggle Diagram
Biological Explanations
Brain Injury
Investigates the relationship between offending behaviour and damage to the brain as a result of injury
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Kreutzer et al (1991) were unable to prove or disprove a cause and effect between traumatic brain injury and violence.
74 patients, they found that 20% had been arrested pre-injury and 10% post-injury.
The study concluded that criminal behaviour might be a result of post-injury changes, including poor judgement
Substance abuse, TBI and crime were indeed interconnected, the researchers said, they did not go so far to conclude that the brain injury causes criminality and violence.
Kreutzer et al (1995) concluded that without the presence of substance use history, TBI was not a risk factor for criminal behaviour
The Amygdala
The amygdala is responsible for controlling human emotions, damage to this area of the brain can result in a person presenting as unemotional or they may react excessively to their emotions as they cannot reduce them
Smaller amygalae have been found among individuals diagnosed with psychopathic personalities as well as those having higher levels of aggression (Pardini et al, 2014)
The conclusion from their study was that individuals with smaller amygdalae were 3x more likely than those with larger amygdalae to exhibit aggression, violence and psychopathic features
However, it is possible to have a smaller amygdala yet not in a psychopathic way
Sham Rage
In 1925, Cannon and Britton introduced the term 'sham rage' to describe an emotional state found in animals
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Narabayshi et al (1963) conducted psychosurgery on human patients with aggressive behaviour by severing their amygdala from the remaining limbic system and found a mood-stabilising effect in the majority of patients over time.
This could show that while there are brain structures that contribute to the likeliness of of aggressive behaviour in individuals, there may be others who have abnormalities but do not act in an unemotional way
When decorticate cats were provoked, they exhibited the emotional behaviour normally associated with rage and aggression, as demonstrated by erect hair, growling and the baring of teeth
They called it sham rage as it occurred without the cognitive influence or inhibitory control of the cerebral cortex
Comes from the temporal region, specifically the amygdala
XYY Syndrome
XYY syndrome is a genetic condition that occurs when a human male has an extra male (Y) chromosome within the 23rd pair of chromosomes. Giving a total of 47 chromosomes
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Not an inherited condition, but randomly at the time of conception
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Theilgaard's study shows a small presence of XYY men among a criminal population. This suggests that it cannot be the only reason for criminal behaviour among men.
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Women also engage in criminal behaviour, including violent crime. As women do not have Y chromosomes, XYY fails to account for criminal behaviour among women.
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Personality
Hans Eyseck
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Eysenck (1990) proposed arousal theory to explain the casual roots of the 3 dimensions of personality
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Activity in the ARAS stimulates the cerebral cortex, which in turn leads to higher cortical arousal
Also explained neuroticism in terms of activation thresholds in the sympathetic nervous system (limbic system) - this includes the hippocampus, amygdala and hypothalamus, and is where emotional states such as fear and aggression are regulated
Rushton and Chrisjohn (1981) investigated delinquent, rather than criminal behaviour. Their study shows clear support for a relationship between high delinquency scores and high scores on both extraversion and psychoticism
They did not ,however, find support for a relationship between delinquency socire and the dimension of neuroticism, leading them to suggest there are key differences between the 3 personality
Somewhat simplistic and fails to consider that a person's reactions or behaviour may differ depending on the situation
Most personality types are consistent over time, but an individual may learn techniques to manage part of their behaviour
Often based of self reported data, this could create a chance for the information to be flawed as displaying response bias
Some studies have shown personality to be a contributory factor, rather than a casual factor
Eysenck believed that a criminal personality displayed the following 3 personality dimensions
- High P scores are aggressive, antisocial, cold and egocentric
- High E scores are sociable, active, lively and sensation-seeking. They need more stimulation from their environment
- High N scores are anxious, depressed and react very strongly to aversive stimuli and have a high degree of instability
Personality Disorders
A personality disorder (PD) is when an individual's way of thinking, feeling or relating to others differs significantly from that of a person without a personality disorder
Narcisstic: a need to be admired, thinks they are the most important and will exploit others to get what they want
Antisocial: often aggressive, ignore rules and does not care about others
Paranoid: distrust of others, takes criticism very personally and can bear grudges
Michael Stone (2007) undertook research to look at the relationship of certain PDs to violent crime. Using personal interviews and looking at media reports of offenders convicted of such offences, he was able to assess the offenders to see if they had a PD. He made the following findings.
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Narcissistic traits were high though not all were severe enough to get a diagnosis of narcissistic PD
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