2.1

• Science for the XYY syndrome

  ‘Super males’

  broader, more manly but low IQ
• Evidence for XYY syndrome

  Jacob’s 1965

  John Wayne Gacy

  stochholm 2012
• What did stochholm find 


  XYY had more convictions for sexual abuse and arson
• What does stochholm‘s findings suggest? 


  More biological reason for crime
• What did Jacob find in 1965


  1 in 1000 men who are free in society would have XYY

  15 in 1000 men who are in prison should have XYY
• What are the assumptions for people who have XYY syndrome

  1) they don’t fully understand their actions 2) they are used as ‘the muscle’ in criminal organisations 3)more likely to get convicted as they look like the stereotyped criminals
• What are the concerns for XYY syndrome

  Is it nurture?

  due to the lowered intelligence. They’re more likely to get caught
• What is the science for adoption studies

  If there is a gene it would be present irrespective or who’s raised them
• what is the assumption for adoption study?

  If we find a criminal behaviour, it is usually like biological parents
• Examples of adoption studies

  Jeffrey Landrogan
• Concerns for adoption studies

  20% concordance rate is a week link

  nurture starts from contraception. E.g. mum taking drugs or alcohol when pregnant
• What evidence is there for twin studies

  Crowe 1972 showed that there is a 5% chance of the child ending up in prison if their adopted mum was there but 50% if biological mum was there

  mednick 1975 found 20% Concordance rate between biological parents and child.

  mednick 1994 found no correlation between child and adoptive parents.
• What is another word for identical twin

  Monozygotic
• What is another word for non-identical twins 


  Dizygotic
• What is a concordance rate

  if One twin had the traits, will the other
• what is the science for twin studies

  If there is a criminal gene, it would be present in all sets of twins
• What is the assumptions for twin studies

  a higher concordance rate would suggest a link
• What is the evidence for twin studies

  Supporting research- many other research around the world

  christianson 1977 - monozygotic twins have 52% chance of both being criminals. Dizygotic twins have 22% chance.
• What are the concerns for twin studies

  The 52% concordance rate suggestd no genetic link.

  the 52% could be upbringing.

  due to identical twins getting treated the same, there is no separate identity.