XYY in crime

Question 1

XYY syndrome

Answer 1

genetic chromosomal mutation - extra Y chromosome on the 23rd pair
1 in 1000 males

Question 2

features of XYY

Answer 2

• above average height
• severe acne
• below average IQ (10-15 lower than sibling)
• learning disabilities in 50% of cases
• more impulsive, lack empathy, aggressive

Question 3

Jacobs et al

Answer 3

over-representation of XYY men in prison - 15 XYY men for every 1000 prisoners
and 3.5% of males at Scottish State Mental Hospital had XYY genetic makeup

• supported by studies of inmates in England, Australia, Denmark and USA

Question 4

Witkin

Answer 4

no direct link between XYY gene and crime
looked at 4591 mean in top height distribution in Denmark and only found 12 cases of XYY
41.7% of these were more likely to be involved in crime but not violent crime

Question 5

weaknesses of XYY

Answer 5

• difficult to determine who has syndrome, 75% of cases not detected
• high social control as Michael Court Brown said all XYYs were best hospitalised just in case they were aggressive - unfair implications, no free will
• hard to distinguish if nature or nurture