Jacobs' XYY Theory

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Created by
Davey Yates

Cards (6)

  • What is Jacobs' XYY theory?
    Males with an extra Y chromosome are more likely to be aggressive and exhibit criminal behaviour
  • What are males with XYY syndrome known as?

    'Super males'
  • What are the statistics of people having XYY syndrome?
    In the male prison population - 15 in 1000
    In the wider population - 1 in 1000
  • What are 2 Strengths of XYY syndrome?
    One Strength - His prison study showed a significant no. of prisoners had XYY syndrome.
    One Strength - Alder et al. indicated that it's possible that aggressive and violent behaviour is at least partly explained by genetic factors.
  • What famous serial killer had XYY syndrome?
    John Wayne Gacy
  • What are 2 Limitations of XYY Theory?
    One Limitation - Theilgaard (1984) researched the traits of XYY men compared to XY men & found that men
    with the XYY chromosome were not associated
    with the characteristic of aggression.
    One Limitation - XYY is very rare (only 1 in 1000 have it) so it does not explain much crime.