[GENETIC THEORIES] Biological Theories of Criminality

Question 1

XYY Theory [Chromosomal Abnormalities]

Explain the XYY ‘Super Male’ Theory

Answer 1

Jacob ET AL.
Some crime may be attributable to a chromosomal abnormality
Not inherited
extra Y chromosome

Males with the ‘Super male’ abnormality are known to be more aggressive as they have extra testosterone in the Y chromosome

Question 2

XYY Theory [Chromosomal Abnormalities]

Explain three of the XYY traits

Answer 2

Delayed Speech development
Below average intelligence
Learning and behavioural problems

Question 3

XYY Theory [Chromosomal Abnormalities]

Explain how the ‘Super Male’ syndrome may act on the brain

Answer 3

LIMBIC SYSTEM
(Controls out emotions and regulates male primitive desires)
Can lead to a male becoming more impulsive and more violent
This can trigger violent criminal acts

Question 4

XYY Theory [Chromosomal Abnormalities]

Explain the research conducted

Answer 4

XYY men are over-represented in the prison population
350 men tested for XYY chromosome abnormality (Prisoners)
Only 9 men had the extra Y chromosome

Question 5

XYY Theory [Chromosomal Abnormalities]

Explain 3 strengths

Answer 5

+ Scientific explanation/approach

+ Some cases where offenders have had an extra ‘Y’ (E.G: John Wayne Gacy)

+ Higher testosterone which is known to lead to higher violence

Question 6

XYY Theory [Chromosomal Abnormalities]

Explain 3 weaknesses

Answer 6

• Not all ‘XYY’ super males are criminals
• Cant explain criminality in women (XX)

-Social and upbringing factors are ignored and only focus on biology

Question 7

XYY Theory [Chromosomal Abnormalities]

Explain how the ‘XXY’ chromosomal abnormality causes criminality

Answer 7

Testosterone can lead to violence

Question 8

[FAMILY STUDIES]

Explain the family studies theory

Answer 8

Looking at families to see if there’s a pattern of criminality to explain biological genetic reasons
Looks at similar behaviours between family members

Francis Galton: Looked at intelligence or genius and founds that this was hereditary

Question 9

[FAMILY STUDIES]

Explain how this can cause criminality

Answer 9

If there is a pattern between family members and crime it can be suggested that there is a strong likelihood that crime is related to families - means criminality is due to genetics

Question 10

[FAMILY STUDIES]

Explain a strength

Answer 10

• Shows a genetic predisposition

Question 11

[FAMILY STUDIES]

Explain 3 weaknesses

Answer 11

• Ignores social factors
• We cannot separate the effect of genetics from the effect of the environment
• Although there is a correlation between criminality and family members, other factors in the environment (unemployment, poor education) could contribute

Question 12

[FAMILY/TWIN STUDIES]

What are the two types of twins

Answer 12

Monozygotic
&
Dizygotic

Question 13

[FAMILY/TWIN STUDIES]

Explain the two types of twins and behaviour as a result of genes

Answer 13

Monozygotic = Identical twins from one egg, shared DNA, same environment, Behave in a similar way

Dizygotic = non-identical, separate eggs, share 50% of DNA, same environment, same as an ordinary sibling

If behaviour is caused by genes - MZ twins should be more similar than DZ twins (Concordance rate - behaving in a similar way)

Question 14

[FAMILY/TWIN STUDIES]

Explain the link to criminality

Answer 14

If both identical twins are criminal, this suggests a very strong link to criminality

Question 15

[FAMILY/TWIN STUDIES]

Explain the supporting evidence for criminal concordance

Answer 15

Christiansen

Studied 3586 pairs of twins to identify higher concordance rates of criminal behaviour in MZ twins (theft, not violent crimes)

Results: MZ twins has a higher % than DZ twins

Question 16

[FAMILY/TWIN STUDIES]

Explain why the twin studies are more useful than family studies

Answer 16

Takes the nature side of the debate into account and looks into the biology - how genetics have an impact on criminality

Question 17

[FAMILY/TWIN STUDIES]

Explain 3 weaknesses

Answer 17

• We are still seeing impact of environment (nurture)
• small samples may not be representative

-in Christiansen’s study there is a difference in the % depending on gender, raising the question about how gender may affect criminal behaviour

Question 18

[FAMILY/TWIN STUDIES]

Explain a strength

Answer 18

MZ shows higher rate of concordance than DZ, shows genetic similarity (E.G: The Krays)

Question 19

[ADOPTION STUDIES]

Explain 3 strengths

Answer 19

+ Adoption studies make it easier to separate the nature/nurture debate

+ Studies show correlation between biological and adoptive parents

+ Mednick ET.AL. suggests both genes and environment are important but genes may be more significant

Question 20

[ADOPTION STUDIES]

Explain 3 weaknesses

Answer 20

• Ages of adoption may mean adopted children have been influenced by their natural parents
• Adoption is not always random
• Practical issues = info about biological parents may not always be available for comparison

Question 21

[BRUNNER SYNDROME - WARRIOR GENE]

Explain 3 strengths

Answer 21

+ Explains criminality in both men and women

+ It’s scientific - can identify if someone has a faulty gene (observable)

+ There is research evidence (Caspi and Brunner)

Question 22

[BRUNNER SYNDROME - WARRIOR GENE]

Explain 3 weaknesses

Answer 22

• Not everyone with a faulty MAOA gene is aggressive or violent
• Cant ignore the role of the environment (Caspi)
• Small numbers of people within the population have this gene in comparison to those offences out there

Question 23

[ADOPTION STUDIES]

Explain the Adoption Studies

Answer 23

Looks at the impact of nurture on children who are raised by their non-biological parents
If child is more similar to adoptive parents suggests nurture (environment) is more important
if more similar to biological parents, suggests the nature (genes) side is more important

(Are criminals born or made??)

Question 24

[ADOPTION STUDIES]

Explain Crowe’s findings

Answer 24

if an adoptee’s biological mother had a conviction the adoptee had a 50% chance of having a conviction
If mother didn’t have conviction -child had 5% chance

(FEMALE FINDINGS)

Question 25

[ADOPTION STUDIES] Explain Mednick ET.AL

Answer 25

14,427 adopted sons criminal records of both biological and adoptive parents Compared adoptee's criminal records with adoptive and biological parents Sons were most likely to have criminal record if biological parents had one (20% concordance rate) 14.7% had criminal record if adoptive parents did ((Suggests that both genes and environment are important but that genes may be more important in explaining criminality))

Question 26

[BRUNNER SYNDROME - WARRIOR GENE] Explain the Warrior Gene theory

Answer 26

Looks into an association between gene and aggressive behaviour

Question 27

[BRUNNER SYNDROME - WARRIOR GENE] Explain having too much and too little of the MAOA gene

Answer 27

Too much = Little serotonin Too little = Too much serotonin

Question 28

[BRUNNER SYNDROME - WARRIOR GENE] Explain Brunner's research and findings

Answer 28

Study was done on Dutch family - defect in male family members (They were all very violent) Blood samples were taken to isolate DNA Mutation on the X chromosome and responsible for the production of the MAOA gene Brunner found all members with this gene were aggressive when angry, fearful or frustrated

Question 29

[BRUNNER SYNDROME - WARRIOR GENE] Explain the MAOA gene

Answer 29

A faulty gene produces an enzyme that control neurochemicals in the brain One problem: The faulty gene can cause an over-production of the enzyme MAOA gene which breaks serotonin down too quickly

Question 30

[BRUNNER SYNDROME - WARRIOR GENE] Explain what can happen when serotonin is broken down too quickly and are low

Answer 30

makes communications between specific brain regions of the limbic system and frontal lobes weaker can be more difficult for prefrontal cortex to control emotional responses

Question 31

[BRUNNER SYNDROME - WARRIOR GENE] Link to criminality

Answer 31

Overproduction of MAOA Gene = Serotonin moderates impulsivity therefore chemical imbalances can cause anti-social behaviour and violence offending Sluggish MAOA Gene = Slows down the metabolism and serotonin and other neurotransmitters - leading to higher levels of serotonin, dopamine and norepinephrine which can lead to aggressive behaviour

Question 32

[BRUNNER SYNDROME - WARRIOR GENE] Explain what happens if the MAOA gene is sluggish

Answer 32

Slows down the metabolism and serotonin and other neurotransmitters - leading to higher levels of serotonin, dopamine and norepinephrine which can lead to aggressive behaviour

Question 33

[BRUNNER SYNDROME - WARRIOR GENE] Explain high levels of serotonin

Answer 33

Can cause aggression and cause people to feel less empathy for other and more willing to harm others Brain cant cope with too much serotonin

Question 34

[BRUNNER SYNDROME - WARRIOR GENE] Explain caspi's research and findings

Answer 34

Large group of individuals Followed from ages 3-20 Looked for maltreatment between 3 and 11 yrs old Looked at their genes Looked at criminal record Findings: Maltreatment = significant predictor of aggression. low activity of MAOA Maltreatment + low activity of MAOA = significant aggression (Strongest predictor of behaviour - combination of factors)

Question 35

[BRUNNER SYNDROME - WARRIOR GENE] Who is the MAOA gene inherited from?

Answer 35

The mother - X chromosome

Question 36

[BRUNNER SYNDROME - WARRIOR GENE] Explain why MAOA gene has more impact on men

Answer 36

Men have higher levels of testosterone

Question 37

What are all the Genetic Theories?

Answer 37

XYY 'Super male' - Jacob Et At. Family Studies Twin Studies Adoption Studies Warrior Gene - Brunner