AC2.1 Describe biological theories of criminality Flashcards
what theories are in biological theories
Physiological theories – focus on criminals physical characteristics
Genetic theories – see that criminality is inherited
Brain injuries and disorders – brain injuries and disorders can cause people to offend
Physiological theories: Lombroso
Lombroso – he argued that criminals were physically different from non-criminals. He spent many years measuring and recording details of heads and faces of thousands of prisoners. From research, he concluded that criminals could be identified by distinctive physical features such as: enormous jaws, long arms. He claimed different types of criminals had different facial features. Lombroso saw criminals as atavistic. They were pre-social, unable to control impulses, had reduced sensitivity to pain which in his view explained why criminals had tattoos. In Lombroso’s view, such people were born criminals that we could identify scientifically by reading their body for physical characteristics.
evaluation of Lombroso
Strength – his research showed the importance of examining clinical and historical records of criminals
Strength – his later work took some limited account of social and environmental factors not just hereditary
Weakness – research since Lombroso failed to show a link between facial features and criminality reducing the validity of Lombroso’s work
Weakness – by describing criminals as like ‘primitive savages’ Lombroso equates non-western societies with criminals. This is a form of racism
Physiological theories: Sheldon:
In Sheldon’s view certain somatotypes linked to criminal behaviour. He identified 3 somatotypes:
Endomorphs – soft, tended to fat, personality is sociable, and outgoing.
Mesomorphs – muscular, very little fat, personality is adventurous, sensation seeking and assertive.
Ectomorphs – thin and fragile, personality is self-conscious and emotionally restrainedl.
Sheldon argued mesomorphs are the somatotype most likely to engage in crime as they’re more likely to be attracted by risk taking and their physique and assertiveness can be important assets in crime
evaluation of sheldon
Strength – other studies replicated Sheldon’s findings. Glueck and Glueck found 60% of offenders in their study were mesomorphs
Strength – the most serious delinquents in Sheldon’s sample were the ones with the most extreme mesomorphic somatotype
Weakness – Sheldon doesn’t account for endo and ectomorphs who do commit crimes. Nor does he explain whether mesomorphs commit crimes other than violence
Weakness – criminals may develop mesomorphic build as a result of needing to be physically tough to succeed in crime. If this is so, criminality causes somatotype
Weakness – labelling may play a role. Mesomorphs may be labelled as troublemakers due to fitting the stereotype, resulting in a self-fulfilling prophecy. Or mesomorphs may attract more police attention due to typification’s.
Genetic theories: Twin studies:
Christiansen (1977):
Christiansen studied over 3,000 twin pairs from the Danish Islands and found higher concordance rates in both male and female MZ twins than in DZ twins.
Lange (1929):
He found that MZ twins showed a much higher degree of concordance than DZ twins for criminal behaviour. 10 of the 13 MZ twins had both served time in prison, whereas only 2 of the 17 DZ twins had such concordance.
evaluation of twin studies
Strength – because MZ are genetically identical, it is logical to examine whether offending behaviour is also identical. Twin studies give some support to genetic explanations due to there being a higher concordance rate for identical twins than fraternal twins
Weakness – if genes were the only cause of criminality then identical twins would show 100% concordance rates, however studies only show this rate to be half or less
Weakness – higher concordance rates between identical twins may be due to shared environment causing similarities in their criminal behaviour rather than their identical genes. It is impossible to isolate and measure the effect of genes separately from environmental effects
Genetic theories: Adoption studies:
Mednick (1984):
Mednick studied 14,000 adopted children and found a high proportion of boys with criminal convictions also had biological parents with criminal convictions, suggesting there’s a link between aggression and genetics. Mednick found no relationship between number of criminal convictions of adoptive parents and their adopted children. However he did find a significant correlation between number of criminal convictions of the biological parents and their offspring
evaluation of adoption studies
Strength – findings of adoption studies give some support to genetic explanation as it shows that adoptees are more likely to have criminal records if their biological parents also had a criminal record
Strength – adoption studies overcome the issue in twin studies where identical twins were brought up in the same household making it impossible to separate out the influence of genes from the environment. Whereas, adoption studies were able to do this, increasing the validity of its findings
Weakness – adopted children are often placed in environments similar to that of their birth family, for example same class and ethnicity. This similar environment may produce similar behaviour
Weakness – many children aren’t adopted immediately after birth so the short time in such environments may be the true cause of their criminality
Genetic theories: Chromosomes:
Jacobs XYY:
XYY syndrome, labelled as ‘super male syndrome’, occurs when males have an extra Y chromosome. Men with XYY syndrome tend to be very tall and well built, and of low intelligence. Jacob et al claim that men with XYY syndrome are more aggressive and potentially more violent than other males. This claim is based on studies of imprisoned criminals where a higher than average proportion of inmates were found to have XYY syndrome. Many had histories of aggression and violent assault. Price and Whatmore found XYY males to be immature and unstable, with a strong tendency to commit seemingly motiveless property crimes.
evaluation of chromosomes
Strength – Jacob et al found an association between XYY syndrome and offenders imprisoned for violent behaviour. Price and Whatmore also found some links between XYY syndrome and property crime which strengthens and supports their theory.
Weakness – even if some violent offenders have the syndrome, it doesn’t prove it is the cause of their violence
Weakness – XYY males may be over-represented in prison, since they are often of low intelligence so are more likely to be caught. Therefore, the sample drawn from prisoners is skewed and not accurate to the general population
Genetic theories: Brain injuries and disorders:
Raine et al (1994):
Raine carried out PET scans to study the living brains of impulsive killers. Damage was found in the pre-frontal cortex in the brains of the criminals, which is the part of the brain that controls impulsive behaviour.
Abnormal brainwave activity:
Brainwave activity is measured by an EEG. Some studies show abnormal EEG readings among clearly insane murderers and psychopathic criminals.
Diseases:
Some brain diseases have been linked with criminal or anti-social behaviour. For example in the 1920’s an epidemic of encephalitis was linked to destructiveness, impulsiveness, arson and abnormal sexual behaviour. Other brain diseases like dementia, Huntington’s and brain tumours have been linked to various forms of deviant or antisocial behaviour.
evaluation of brain injuries and disorders
Strength – brain injury has led to major changes in an individual’s personality including criminality, for example Phineas Gage suffered a brain injury which changed his personality and made him become bad tempered and nasty which wasn’t his personality before the accident.
Strength – there is a correlation between abnormal EEG readings and psychopathic criminality
Strength – prisoners are more likely than non-prisoners to have a brain injury
Weakness – crimes caused by brain injury or disease are rare. Sufferers original personality is more important in whether they engage in crime
Weakness – it is not clear that abnormal brainwave activity causes psychopathic criminality. Some psychopaths have normal EEG readings and some non-psychopaths have abnormal EEG readings
Biochemical/Neurochemical: Blood sugar levels:
low blood sugar can trigger aggressive reactions. studies show a link between low blood sugar and alcohol abuse. drinking large quantities of alcohol can increase low blood sugar and increase aggression. alcohol consumption is closely linked to crimes of violence.
other substances we ingest have also been linked with anti-social behaviour. these include: food additives and diet, allergens, vitamin deficiencies and lead pollution. they affect various biochemical processes in the body and this in turn can affect behaviour. for example, vitamin B deficiency has been linked to erratic and aggressive behaviour.
self control requires glucose therefore people who have difficulty metabolising glucose are at a greater risk for aggressive and violent behaviour.
Biochemical/Neurochemical: Sex hormones
overproduction or underproduction of hormones may cause emotional disturbances that lead to criminal behaviour. the male sex hormone testosterone has been linked with crimes such as murder and rape. Similarly, Ellis and Coontz point out that testosterone levels peak from puberty to the early 20’s and this age range correlates with the highest crime rates in males
pre-menstrual tension, post-natal depression and lactation have all been accepted as partial defences for women charged with crimes ranging from shoplifting to infanticide on the grounds that the hormones involved have affected the defendant’s judgement, mood or self-control. for example, in 1980 two British women argued legal responsibility was diminished by pre-menstrual syndrome and had murder conviction diminished to manslaughter.
