Unit 2 LO2&3

• Biological Theories of Criminality

  Physiological Theories and genetic theories
• Lombroso: Born Criminals
• Lombroso


  • Criminals are physically different from non-criminals
  • Measured many criminals' heads and faces
  • Criminals more likely to have large jaws, long arms, aquiline noses
• Atavism


  Criminals are throwbacks to primitive stage of evolution – pre-social, impulsive, reduced sensitivity to pain
• Lombroso's further work


  • Insane criminals, epileptic criminals
  • Criminaloids – product of environment
• Evaluating Lombroso


  • First person to study crime scientifically
  • Shows importance of clinical and historical records of criminals
  • Helps to focus on how prevention not punishment
  • No further evidence to link facial features and criminality
  • Did not compare with control group of non-criminals
  • Racist. Equates criminals with savages/ non-western society
• Sheldon: Somatypes Theory


  Somatype (body type) is related to criminality
• Sheldon's study


  • Looked at body types and compared with likelihood of criminality
  • Mesomorphic somatype most likely to be criminal
• Reason for Sheldon's findings

  Attracted by risk-taking and their physique and assertiveness are important assets in crime
• Evaluating Sheldon


  • Other studies replicate findings
  • Most serious delinquents had most mesomorphic bodies
  • Criminality likely to be a combination of biology and environment
  • Mesomorphic build may be result of criminality
  • Social class might be true cause of offending and mesomorphy
  • Mesomorphs more likely to be labelled
• Atavism


  The idea that criminals are 'throwbacks' to more primitive stage of evolution
• Endomorph


  Rounded, soft bodied, lacking muscle. Sociable, relaxed, outgoing
• Ectomorph


  Thin, fragile, lacking fat and muscle. Flat chested, narrow hips and shoulders, thin face. Self conscious, emotionally restrained, thoughtful
• Mesomorph


  Muscular, hard-bodied, little fat, strong limbs, broad shoulder, narrow waist. Adventurous, sensation-seeking, assertive, domineering
• Physiological theories


  These biological theories claim that the physical features of criminals differ from non-criminals
• Biological theories


  Criminals are biologically different from non-criminals and this difference causes them to commit crime
• Genetic Theories


  Criminality is the result of genes inherited from biological parents
• Twin studies


  • If crime is genetic – identical (Mz) twins should have identical criminality
  • Christiansen: Concordance in criminality Mz = 52% vs Dz = 22%
• Adoption studies


  • Adoptees share environment of adoptive parents/genes of biological parents. If genetic, criminality will match biological parents more
  • Mednick et al: birth parent concordance = 20% vs. adopted parent concordance = 14.7%
• Evaluating Twin and Adoption Studies

  • Twin & adoption studies give some support to genetic explanations
  • Adoption studies overcome the problem of isolating genes and environment
  • Research design of Adoption studies is logical (nature vs nurture)
  • If criminality was only genetic MZ twins would have 100% concordance
  • It is impossible to isolate genetic effects fully from environmental ones
  • Adopted children often placed with similar families to their birth family
• Jacob's XYY Study


  XYY syndrome in males makes them genetically predisposed to criminality
• Jacob's XYY Study


  • Compared rate of XXY in imprisoned criminals with general population
  • Higher than average proportion of inmates had XYY
  • Very tall, well-built, low intelligence, high aggression, violent
• Evaluating Jacob's XYY Study

  • Jacob et al found association with XXY and violent prisoners
  • Price & Watmore found links with XYY and property crime
  • Having the syndrome doesn't mean that is the cause of crime
  • XXY men fit stereotype of violent offenders – labelling theory
  • Low intelligence of XYY may give higher chance of being caught
  • Syndrome is too rare to explain much crime
• Genetic explanation


  Criminality is the result of genes inherited from biological parents
• Monozygotic


  Identical twins that share 100% of the same genes
• Dizygotic


  Non-identical twins that share only 50% of the same genes (like ordinary siblings)
• Environmental explanation


  Criminality is the result of the surroundings a child grows up in
• Chromosome


  Made from DNA and protein. Carry genetic information we inherit from our parents. Most people have 23 pairs
• Super-male


  Another term for XYY syndrome. Those affected carry an extra Y (male) chromosome on one of their 23 pairs
• Brain Injuries and disorders

  • Brain injury can change personality and are more common in prisoners
  • Some brain diseases have been linked with criminal or anti-social behaviour. Dementia, Encephalitis Lethargica' brain tumours, Huntington's chorea
  • Some studies show abnormal EEG readings in psychopathic criminals
• Evaluating Brain Injuries and disorders

  • A few extreme cases do show brain injury leads to changes in behaviour including criminality
  • Some correlation between abnormal EEG readings and psychopathy
  • Prisoners are more likely than non-prisoners to have a brain injury
  • Crimes caused by brain injury or disease are rare. Original personality more important
  • Abnormal EEG not necessarily the cause and not found in all psychopaths
  • Prisoner's higher likelihood of brain injury may be affect of criminality mot cause – e.g. getting into fights
• EEG


  Electroencephalogram – measures brain activity
• Biochemical Explanations


  • Sex Hormones: Males - Ellis and Coontz: testosterone peaks puberty to early 20s – same as criminality
  • Sex Hormones: Females - PMT, PND, Lactation all used as defence in court – affected mood/self-control
  • Blood sugar - Hypoglycaemia linked to aggression
  • Substance abuse - Prescription and illegal drugs and alcohol linked to crime. Can lead to increased aggression
  • Other substances - Lead, tartrazine linked to hyperactivity. Vit B deficiency linked to erratic behaviour
• Evaluating Biochemical Explanations


  • Biochemical factors recognised by the courts
  • Sex hormones, alcohol, drugs all known to affect mood/behaviour
  • Biochemical processes may need an environmental trigger too
  • Some studies find testosterone not linked to physical aggression
  • Infanticide may be caused by isolation rather than hormones
• Testosterone


  Male sex hormone linked to aggression, murder and rape
• PMT


  Pre-menstrual tension – fluctuation in female sex hormones
• PND


  Post-natal depression – used as defence in infanticide
• Lactation


  Breast-feeding. Used as defence in female crimes
• Hypoglycaemia


  Low blood-sugar. Linked to aggression and alcohol abuse
• General criticisms of biological theories

  • Biology may give potentially criminal characteristics but need environmental trigger too
  • Only studying criminals means we don't know about those who got away – can't genralise
  • Most biological research only tells us about male criminality
  • Biological theories look for universal explanations, but crime varies over time, place and culture