Genetic theories

Question 1

twins studies

Answer 1

looked at whether criminality is inherited
- monozygotic (MZ) identical twins that share 100% DNA
- dizygotic (DZ) un-identical twins that share 50% DNA
Christiansen studies twins in Denmark - MZ 52% concordance rate
22% for DZ

Question 2

adoption studies

Answer 2

compares child to adopted and biological parents
Mednick studied adopted sons and criminality
- biological fathers, a concordance rate of 20% was found
- adopted fathers, a concordance rate of 14.7% was found

Question 3

jacob XYY

Answer 3

supermale syndrome, extra Y sex chromosome
often have characteristics of low intelligence, tall, well built and increased aggression
Price & Whatmore - studied criminals in psychiatric unit, more had the XYY and had a history of aggression