Criminology Unit 2 AC 2.1

Biological theories of criminality (2)

Genetic

• Twin studies

• Adoption studies

• XYY study

physiological

• Lombroso

• Sheldon

• Brain abnormality

What does genetic theories mean?

If crime is inborn, it is presumably passed down form parent to child which can explain why crime often runs in families.

For example, west and farrington found that children with a parent who has a criminal record are 3 times more likely to have a criminal record themselves. Also Osborne and west found that sons of criminal fathers were much more likely to have a criminal record themselves.

Genetic theories explain that family members who are blood relatives share the same genes and there fore if one member has criminal genes it is likely the other members will too.

Genetic theories 1 - twin studies

Identical or monozygotic (MZ) twins share the same genes as they both developed from the same fertilised egg. Therefore if one twin in a criminal, according to this theory, the other should be as well.

Christiansen’s study: studies 3586 twins in Denmark and found a 52% concordance rate between MZ twins meaning that where one twin was a criminal there was a 52% chance the other would also be. There was only a 22% concordance rate between non-identical or dizygotic (DZ) twins.

Strengths of twin studies

• provides info/evidence about how crime runs in families

• Monozygotic twins are identical therefore appears logical to assume their offending would be too

• Johannes et al found 10/13 monozygotic twins had served time in prison whereas 2/17 dizygotic twins had such a concordance

• The biological relationships occur naturally, so they are natural experiments

Weaknesses of twin studies

• small samples so won’t represent a whole population and can’t generalise (low validity)

• If genes were the only cause of criminality monozygotic twins would show 100% concordance rate, Christiansen only found found 52%

• Parents treat identical twins more alike than non identical twins. Identical twins may feel closer so they act more similarly

Genetic theories 2 - adoption studies

Compares adopted children both to their adoptive parents and biological parents.

Mednik et al looked at data on over 14,000 adopted sons from 1924 to 1947. They found sons were more likely to have a criminal record if a birth parent also did.

A concordance rate of 20% between an adopted child and a birth parents and a concordance rate of 14.7% between an adopted child and an adoptive parent.

Strengths of adoption studies

• adoption studies overcome the problem that twin studies face where children are brought up in the same home

• Studies by Hutchins and Mednick show a link/correlation between offspring who are adopted and their biological parents

Weaknesses of adoption studies

• Gottfredson + Hirschi argue that adoption studies show that genes have little effect on criminality

• Many children aren’t adopted immediately after birth but remain with their biological family for some time

• Information about biological parents isn’t always available

Genetic theories 3 - XYY study

Chromosomes are strands of DNA which carry the genetic information we inherit from our parents. Humans should have 46 (23 pairs).

Women = XX

Men = XY

What is XYY syndrome?

When and extra Y chromosome is present. Normally labelled ‘super male syndrome’. Men with XYY syndrome tend to be very tall, well built, low intelligence. Jacob et al claim men with syndrome tend to be more aggressive and violent.

In prisons 15/1000 inmates suffer from this abnormality but in general there’s just 1/1000 in the general population.

John Wayne Gacy had XYY syndrome

Strengths of XYY studies

• study by prince + whatmore found a link between property crime and XYY

• Jacob et al found an association between XYY syndrome + offenders imprisoned for violent behaviour

• 15 in 1000 prisoners is a substantial figure, providing the theory with credibility

• Studies by Alder et al further emphasised the link between aggression and genetics

Weaknesses of XYY studies

• XYY males are over represented in samples drawn from prisoners + this overstates the importance of the syndrome as a possible cause of crime. XYY may be over represented in prison due to low intelligence which makes them more likely to be caught.

• There isn’t much proof that the syndrome causes violent behaviour- Theilgaard refuted it

What does physiological theories mean?

They focus on a persons physical form as an indicator of criminality. They suggest the physical features of criminals are different from non-criminals.

Physiological theory 1 - Lombroso’s theory: born criminals

He put his first theory forward in 1876 and was known as the ‘father of modern criminality’.

He argued criminals are physically different from non-criminals. He studied many criminals heads and faces are concluded they could be identified by:

• large jaws

• High cheek bones

• Handle shaped ears

• Long arms

He also claimed that different criminals have different facial features:

• murderers have curly hair, bloodshot eyes and aquiline noses

• Thieves had flattened noses

• Sex offenders had thick lips and protruding ears

What is atavism?

Lombroso saw criminals at atavistic: a separate species between modern and primitive humans. They weren’t able to control their impulses and had a reduced sensitivity to pain. He said they were like savages or apes.

He studied 383 dead criminals and 3,839 living ones. He concluded that 40% of criminal acts could be accounted for by atavistic characteristics. Therefore he concluded people were born criminals

A study in China supports this theory- 1,856 photo ID’s of Chinese men (half criminals half not) were entered into an AI programme. Although it wrongly flagged innocent men as criminal 6% of the time, it correctly identified 83% of criminals.

Strengths of Lombroso

• he was the first to study crime- people used to believe crime was a moral or religious issue

• By arguing that offenders were not freely choosing to commit crime, he helps us to focus on how we might prevent further offending rather than simply punishing offenders

Weaknesses of Lombroso

• by describing criminals as ‘primitive savages’ Lombroso equates non-western societies with criminals: this supports the idea that the theory is racist (certain features e.g a big nose)

• Lombroso failed to compare his findings on prisoners with a control group on non-prisoners. If he did, he may have found similar characteristics among this population in which case his explanation would be invalid

• Research since Lombroso has failed to show a link between facial features and criminality

Physiological theory 2 - Sheldon’s theory: somatotypes

Sheldons theory shares Lombroso’s idea that criminal behaviour is linked to physical form. He examined 4,000 photos of men to look at their body types. He came up with 3 body types:

Endomorphs - rounded, soft and tending to fat, they lack muscle or tone and have wide hips. They are sociable, comfortable and outgoing

Ectomorphs - thin, fragile and lack fat and muscle. Flat chested, narrow hips and shoulder and thin face and high forehead. They are self-conscious, emotionally restrained and thoughtful

Mesomorph - muscular and hard bodies, very little fat, broad shoulders and a narrow waist. They are adventurous, sensation-seeking, assertive and domineering

He argued mesomorphs are the somatotype most likely to be criminals as they are most likely to be attracted to danger

Strengths of Sheldons theory

• other studies have replicated his findings e.g Glueck + Glueck found 60% of offenders in their study were mesomorphs

• Most serious offenders is Sheldons study were the ones with extreme mesomorph bodies

Weaknesses of Sheldons study

• criminals may develop a mesomorphic build because of needing to be physically tough to succeed

• Social class may be the cause of offending and mesomorphs because offenders are mainly working-class men who are more likely to have a manual job therefore having a common mesomorphic build

• Sheldon doesn’t consider endomorphs and ectomorphs who do commit crimes, he also doesn’t explain if mesomorphs commit crimes other than violence

Physiological theory 3 - brain abnormality

• several studies have suggested damage to the pre-frontal cortex of the brain can cause individuals to have altered behaviour like being more immature and loss of self-control. Some studies show prisoners are more likely than non- prisoners to have damage to their brains.

• Raine et al used PET scans to study the living brains of impulse killers. Damage was found in the pre-frontal cortex

• Other brain diseases like dementia, Huntington’s chorea and brain tumours can also be linked to criminal behaviour

Strengths of Brain abnormality

• in some extreme cases brain injury has led to major changes to an individual’s personality and subsequent behaviour

• Dr Raine studied 41 murderers who pleaded not guilty by reason of insanity. He found reduced activity in their pre-frontal cortex and abnormalities in the activity of the limbic system, responsible for decision making and impulse control

Weaknesses of brain abnormality

• brain abnormalities could be causing the criminal behaviour but it would also be possible that the criminal behaviour may have led to a reduction in brain activity. E.g more likely to fight than non-offenders

• There appears to be some complexity surrounding this theory of criminal behaviour as to establish whether the cause of criminality is linked to nature or nurture

Physiological theory 3 - biochemical

Biochemical substances and processes have been suggested as possible causes of criminality due to their effect on brain chemistry and mental processes.

Sex hormones (testosterone)

Willie and Beier found 99 castrated sex offenders, they had lower re-offending rates than 35 non-castrated sex offenders. From the castration, they had lower testosterone levels

Male sex hormone testosterone has been linked with crimes like murder and rape. Ellis and Cootz point out testosterone levels peak between puberty and the early 20’s. This age range has the highest amount of crime rates in males. If people take steroids to increase testosterone levels they can become more aggressive e.g Horace Williams beat a man to death

In women, pre-menstrual tension, post-natal depression and breastfeeding have all been accepted as partialdefences to a range of crimes on the basis that hormones involved have affected a woman’s judgement

Serotonin in biochemical explanations

Some studies show that low levels of serotonin can link to more aggressive behaviour.

Scerbo and Raine conducted a meta-analysis on 29 studies into anti social adults and children and found low levels of serotonin in all of them.

Strengths of biochemical explanations

• testosterone levels and male offenders both peak around the same age, therefore suggesting that hormones do affect criminal behaviour

• Biochemical factors are recognised by the courts, the law of infanticide states that is a mother kills her baby from post-natal depression, she has a partial defence to murder

Weaknesses of biochemical explanations

• biochemical processes may predispose some individuals to offend but it may require an environmental trigger to actually start offending

• Schalling found that high testosterone levels in young males often lead to verbal aggression not physical aggression

• Scarmella and brown found that testosterone levels do not greatly affect aggression levels in most men