Biological Explanations Of Crime Flashcards
What are the four explanations for criminal behaviour?
Brain injury
XYY syndrome
Amygdala
Personality
How can the amygdala be used to explain criminal behaviour
Responsible for controlling human emotions and damage can result in lack of emotion or an excessive reaction to their emotions due to lack of control.
Smaller amygdala found in those diagnosed with psychopathic personalities and aggression. 3x more likely than those with normal size amygdala to exhibit aggression and violence.
Explain the term sham rage in relation to the amygdala
Cannon and Britton used this to describe emotion in animals. After severing neutral connections to the cortex, when provoked aggressive behaviour was shown such as growling. This originated from the temporal region including the amygdala and upon being ablated the animals became placid.
What did Raines 1997 study find in relation to the amygdala?
Significant difference in brain structure of murderers and control participants especially amygdala. 41 pleading NGRI and control injected with tracer which upon being attached to glucose showed brain activity in PET SCAN.
Results/ different amygdala and less glucose metabolism in murdererers brain— impulse.
State a gender difference for crime
Neurobiology involved in empathy is different in males and females, more empathy related circuitry in females.
Strengths and weaknesses of amygdala as a theory.
Good/ narabayahi et al- psychosurgery on aggressive humans by severing their amygdala from limbic system and found mood stabilising effect in patients over time.
Neuroimaging is used in studies- reliable as can be analysed multiple times
Bad/ reductionist- cannot be only factor to determine psychopath- and underplays complexity of brain and how amygdala works alongside other areas of brain
How can brain injury explain criminal behaviour
Misuse of drugs or alcohol or an injury may cause injury. Alcohol affects the CNS and interferes with B1 absorption.
Individuals may change post injury to behaviour untypical of before. If amygdala injured— irritable and aggressive.
What did Williams et al find in 2010
60% of 196 prisoners received some form of Brain injury and adults were relatively young at the time of admission than those without brain injury. The injury affected their development of temperance and judgement making them engage in risky behaviour.
What is the relation between gender and brain injury
NHS- young people at risk with a TBI and affects 8.5% with males more at risk.
Social factors- males more brain injuries than females
Weaknesses of brain injury as explanation of criminal behaviour
Reductionist- offenders have history of substance abuse meaning they may have past history. This means there are multiple factors that may be responsible for criminality not just the brain injury.
Kreutzer et al (1990) unable to establish causality with brain injury and violence. 74 patients- 20% arrested pre injury and 10% post injury. So criminal behaviour may be due to post injury changes.
How does XYY lead to criminal behaviour?
Genetic condition- male has extra y Chromosome on 23rd pair. Occurs in 1/1000 men.
Normal development but may grow faster and may be less mentally capable. Also have acne and leads to men being overly aggressive and lacking empathy. ‘Super male’
Evaluate XYY as explanation of criminal behaviour
Bad:/ determining the rate of XYY among criminal population is resource intensive. It is not practical to evaluate all genetics to find prevalence.
Theilgaards study- small presence of XYY men in criminal population. So cannot be only reason for criminal behaviour or would be 100%= reductionist. Due to XYY men being less smart the reason for criminality may be learning difficulty rather than XYY due to similarity.
Cannot explain women’s criminal behaviour.
How can personality account for criminal behaviour?
Hans Eysenck examined extraversion, introversion, neuroticism, stability, and psychoticism. Concluded that PEN traits lead to criminality.
Explain the arousal theory by Eysenck
Extraversion is explained by cortical arousal via the ascending reticular activating system (ARAS)
Activity in the ARAS stimulates the cerebral cortex leading to higher cortical arousal. Extroverts have underactive ARAS so need more stimulation. This means they will be make risk taking than introverts as they need more stimulation that introverts.
Neurotic individuals- greater activation levels and lower thresholds in the limbic system which makes them more upset at minor stresses.
What is the relation between gender and personality with crime?
Testosterone- explains psychotocism and men are high in psyhotocism.
Gur et al- women have larger limbic system in the frontal area- and so have more control over impulses and are less psychotic.
