Biological theories Flashcards
physiological theories
Lombroso - ‘born criminals’ examined convicts dead and alive - atavistic features, large ears, long arms, dark skin
Sheldon - ‘somatotypes’
endomorph (round, lack muscle, sociable, relaxed), ectomorph (thin, narrow, self conscious, emotional) mesomorph (muscular, broad, adventurous, assertive)
Genetic theories
Twin studies - MZ - identical 100% DNA, DZ - 50%
if DNA is inherited MZ both would be criminals
Christiansens - Denmark - MZ 52% concordance rate
22% for DZ
Adoption studies - comparing biological and adopted parents to see if criminality is inherited
Mednick et al - adopted sons in Denmark, biological parents with criminal record - 20%, adopted 14%
Jacob XYY - extra Y sex chromosome, often low intelligence, tall, well built and more aggressive
Price&Whatmore - studied criminals in psychiatric unit, more had the XYY and had a history of aggression
Brain injuries and disorders
Phineas Gage - iron rod through skull, now used inappropriate language, ruder, acted violently - personality change due to brain injury
Disorders - Encephalitis lethargica among aggressive children, dementia, huntington’s
EEG - electroencephalograph, measures brainwave activity
Biochemical explanations
Sex chromosomes - males, testosterone over or under production
Ellis and Coontz - testosterone peaks at 20’s which links with high crime rates
females, pre-menstrual tension may explain crime hormones effect judgement
Blood sugar levels - hypoglycaemia, can trigger aggression
Substance abuse - Saunders, alcohol results in 1,000 arrests daily Flanzer, 80% of family violence results from drugs or alcohol
Other substances - vitamin D deficiency linked to aggression
