6.1.1 XYY

Question 1

How is XYY syndrome developed?

Answer 1

> Considers chromosomal abnormalities, not hereditary but from random mutations in the 23rd pair
23rd pair
Sex chromosome
Link- men have XY, extra Y chromosome = incr testosterone so incr risk of aggression

Question 2

What is the process of XYY development and who does it affect?

Answer 2

• 1 in 1000 men
• Males only
• Occurs randomly during sperm cell formation where error in cell division (nondisfunction) which results in sperm cells having an extra copy of ‘Y’ chromosome.

Question 3

Physical traits of XYY?

Answer 3

• Taller than avg
• hypotonia(low muscle tone), - - clinodactyly (curved pinky finger)
• macrodontia (unusually large teeth)
• ocular-hypertelorism (widely spaced eyes)
• scoliosis
• cystic acne during teens

Question 4

Behavioural traits of XYY?

Answer 4

• ADHD
• Autism
• Impulsivity
• Defiant behav

Question 5

How can XYY explain criminal behaviour?

Answer 5

> Extra ‘Y’ may act on brain’s limbic system ( regulates impulsivity+ emotions) and can trigger criminal behav eg. opportunistic
More physically active males may act on anti-social behav eg crimes

Question 6

What are the gender differences for XYY?

Answer 6

> Due to women having XX, it’s impossible for them to develop 2 YYs/ XYY syndrome which is linked to incr crim behav

Question 7

EACH-Evidence

Answer 7

1.P-Stockholm (2012) supports
E- Found from 161 males, a sig incr in convictions of males w XYY compared to general indicidences from gen population w XY controls
E- S, suggests extra ‘Y’ chromosome’s increase in testosterone and therefore aggression, which contributes to criminal behaviour
2.P- Jacob et al (1965) supports
E- Found a link between XYY prison population, the norm being 1/1000, but in this prison it was 15/1000
E- Same as 1

Question 8

EACH-Application

Answer 8

P- Yes
E- If syndrome is found early (25% identified at birth), then issues of criminality can be addressed
E- This may prevent negative labelling + prejudice arising from the syndrome, which can reduce the likelihood of criminality

Question 9

EACH-Criticisms

Answer 9

1.P- Cannot account for all crime across both genders
E- XYY only affects males
E-W, can’t provide an explanation of females committing crimes
2.P- Theilgaard (1984) found XYY males have lower lvls of intelligence
E- Argued that incr lvls of crime may be due to learning difficulties associated w condition rather than condition itself
E- Therefore suggesting that having genotype XYY may not be direct cause of criminality

Question 10

EACH-How good?

Answer 10

1.P- Can’t establish cause + effect
E-Only shows relationship between having XYY and committing crimesd
E- May be other factors contributing to conviction rates eg socioeconomic backgrounds > genetics
2.P- Difficult to identify
E- No way to see chromosomes
E- So Jacob’s syndrome is putting a label on something that can’t be defined so diagnosis is difficult, may be incorrectly diagnosed causing retrospective labelling and prejudice for person in life, incr likelihood of criminality