2.1 Biological theories of criminality

Question 1

What are the 2 main groups of theories you need to know?

Answer 1

Physiological and Genetic theories

Question 2

Key assumption of physiological theories.

Answer 2

Criminality is caused by the physical traits of individuals.

Question 3

Key assumption of genetic theories.

Answer 3

Criminality is inherited from family members

Question 4

Key assumption of brain injuries/disorders

Answer 4

Criminality is caused by abnormalities or neurological differences compared to non-criminals.

Question 5

Key assumption of Biochemical explanations

Answer 5

Criminality is caused by hormones or other chemicals

Question 6

Name the 2 physiological theories.

Answer 6

Lombroso’s theory of atavism

Sheldon’s theory of somatotypes

Question 7

Lombroso’s research

Answer 7

Lombroso (1876)

Examining the skulls of deceased criminals, and the facial features of prisoners, Lombroso proposed the ‘atavistic form’ theory of criminality.

Atavistic form refers to the traits that Lombroso found to be common in prisoners and the deceased criminals.

Question 8

What does Lombroso argue?

Answer 8

Lombroso (1876) argued that criminals were physically different to non-criminals.

Question 9

Lombroso’s atavistic features include…

Answer 9

• Enormous jaws
• Large eye sockets
• Prominent eyebrow arches
• High cheekbones
• Handle – shaped ears
• Exceptionally long arms
• Flat noses were found more often in thieves and pointy noses were more common in murders.

Question 10

Key terms for Lombroso’s theory.

Answer 10

Throwbacks to an earlier primitive stage of evolution.

Pre-social

Unable to control their impulses

Reduced sensitivity to pain (tattoos)

‘Savages’

Apes.

Atavistic

Question 11

Sheldon’s research

Answer 11

Sheldon (1949)

Sheldon examined photographs of 4000 scantily clothed men and put forward the 3 somatotypes.

Sheldon gathered a sample of college students and delinquents. He rated how mesomorphic they were on a scale of 1 (low) to 7 (high). Delinquents were rated more mesomorphic than college students (4.6 compared to 3.8)

Question 12

Endomorph

Answer 12

Rounded, soft and tending to be fat, lacking muscle or tone with wide hips.

Their personality is sociable, relaxed comfortable and outgoing.

Question 13

Ectomorph

Answer 13

Thin and fragile, lacking both muscle and fat. They are flat chested, with narrow hips and shoulders, a thin face and high forehead.

Their personality is self - conscious, fragile, inward looking, emotionally restrained and thoughtful.

Question 14

Mesomorph

Answer 14

Muscular.

Most likely to end up committing crime, as they are more likely to be attracted to the risk taking it involves and their imposing physique and assertiveness can be important assets in crime.

Question 15

Genetic theories: What is the 1961 Cambridge study?

Answer 15

Delinquent Development (a longitudinal study).

The study found that out of 397 families, half of all criminal convictions came in just 23 families.

Question 16

What do Monozygotic and Dizygotic refer to?

Answer 16

Monozygotic twins are 100% genetically identical (they both developed from the same fertilised egg).

Dizygotic twins are not 100% identical to each other.

Question 17

Why are twin studies used to study the link between genetics and criminality?

Answer 17

Twin studies focus on identical twins (monozygotic twins) who are 100% genetically identical. Therefore, if one twin is criminal, the other twin ought to be criminal too.

Identical twins are also compared to non-identical twins (dizygotic twins), who are not 100% identical to each other. If criminality is genetic then you would expect more identical twins to be both criminal than non-identical twins.

Question 18

Twin studies: What is the key study you need to know?

Answer 18

Christiansen’s (1977) twin study of criminal behaviour. He studied 3,586 twin pairs in Denmark.

Concordance rate for male MZ twins = 35%
Concordance rate for male DZ twins = 13%

Evidence that criminality is genetic.

Question 19

Why are adoption studies used to study the link between genetics and criminality?

Answer 19

Adoption studies compare adopted children both to their biological birth parents and to their adopted parents.

An adopted child (especially if adopted after birth) shares the same environment as their adoptive parents, but the same genes but as their biological parents.

If we find that the adoptee’s behaviour in regard to criminality is more similar to their birth parents’ behaviour, this would support a genetic explanation.

Question 20

Adoption studies: What is the key study you need to know?

Answer 20

Mednick et al (1947) examined data on over 14,000 adopted sons in Denmark from 1924 to 1947.

They found that sons were more likely to have a criminal record if a birth parent also had a criminal record (a concordance rate of 20%). This supports a genetic explanation.

By contrast, they found that a smaller proportion (14.7%) had a criminal record if their adoptive parent had one.

Question 21

What is Jacob’s XYY theory?

Answer 21

Jacob’s XYY theory

Abnormality of the sex chromosomes is another possible genetic cause of criminality.

One abnormality is an extra Y (male) chromosome. This is known as the XYY syndrome and has been labelled ‘super male syndrome’.

Men with XYY syndrome tend to be tall and well built, and of low intelligence.

Jacob et al (1965) claimed that men with the XYY syndrome are more aggressive and potentially violent than other males.

He studied imprisoned criminals, such as those in secure psychiatric hospitals, where a higher- than- average proportion of the inmates were found to have XYY syndrome.