CRIM 103 Lecture Notes - Neurotrophic Factors, Xyy Syndrome, Twin Study

• School: Simon Fraser University
• Department: Criminology
• Course: CRIM 103
• Professor: Jennifer Wong

Document Summary

Nature via nurture not one or other. If genetics are responsible for crime, we cannot do anything about it: genetics and crime. Dugdale (1877): traced juke family 1750-1870; 709 descendants, ~20%. (~40% on welfare) Farrington"s cambridge study (1998): cannot determine relative impact of genetics vs. environment. Compare behavior to examine genes vs. environment. Prenatal & living experiences affecting twins in same/different ways. Nonshared influences increase with age; shared decrease (gender, one twin sick/injured, different treatment, different teachers/peer groups) Degree to which pairs of subjects both show particular behavior or condition. 20 pairs of mz twins & 20 pairs dz twins. If 10 pairs of mz have same iq score, concordance = 50% If 5 pairs of dz have same iq, concordance = 25% Raine (1993) reviewed 13 twin studies: 52% concordance for mz; 21% for dz. Genes predispose; life experiences increase or decrease that risk.