Cause and effect:Longitudinal studies

• Do defects in amygdala function lead to criminal behaviour or does criminal behaviour cause changes in amygdala function?
• Pardini et al


  503 males from 1986-1987 at age 6 or 7.

  Identifying 56 men with a history of aggressive behaviour 20 years later.

  Using fMRI scans,found that high aggression levels over the 20 year period were linked to lower amygdala volume.This consisted in a follow-up study 3 year later
• High predictive validity