psychlotron org uk Todays session You are learning
- Slides: 11
psychlotron. org. uk
Today’s session You are learning to. . . • Interpret, evaluate and draw conclusions from evidence • Transfer concepts and skills from one topic to another • Learn effectively from lectures psychlotron. org. uk You are learning about. . . • Biological theories of offending
psychlotron. org. uk • Later on, I will be giving you a lecture on this. But first, I want you to use your psychological skills of interpretation and evaluation to anticipate what I’m going to tell you.
psychlotron. org. uk Is there a gene for crime?
No. There isn’t. • ‘Lombrosian’ view: – Single defective gene responsible • Modern behavioural genetics: psychlotron. org. uk – Polygenetic influences – Complex interactions with environment – No assumption of defect
Two questions • Is there a genetic influence on crime? – Family history studies – Twin studies – Adoption studies psychlotron. org. uk • If so, how does the influence operate?
Family history studies • Osborne & West (1982) – Father has a criminal conviction – 40% of sons do – Father has no criminal conviction – 13% of sons do • Consistent with genetic influence psychlotron. org. uk – Also with learning/environment – Suggests genes do not determine criminality
Twin studies • Early studies strongly suggested genetic influence but flaws in sampling, determining zygocity. • More recently: • Low MZ concordances – influence not strong • Confounding effects of more similar treatment for MZ psychlotron. org. uk – Christiansen (1977): MZ 35%; DZ 13% – Dalgard & Kringlen (1976): MZ 26%; DZ 15%
Adoption studies • Generally found that adopted children more similar to biological than adoptive parents. • Supports genetic hypothesis but: psychlotron. org. uk – Issue of what is being inherited (e. g. alcoholism) – Could be prenatal influences, not genetic – Age at adoption – early influences?
What is being inherited? • Hollin (1992) gives three suggestions: • Difficult to resolve because of enormous complexity of interactions • Lots of biological correlates of criminality; few obvious causes. psychlotron. org. uk – Abnormal CNS e. g. Low IQ; ADHD – Abnormal ANS e. g. Lack of responsiveness – Abnormal endocrine e. g. Influence of testosterone
psychlotron. org. uk • Which bits had you already worked out? • Which bits were new or unexpected given your own interpretation?
