AC 2.1 Biological Theories of Criminality

• What do biological theories focus on?

  -the idea that physical characteristics make people more likely to commit crimes

  -these can be genetic and therefore inherited, which supports the nature argument
• What are the two types of biological theories?

  Physiological and genetic
• What are physiological theories?


  the idea that physical characteristics are connected with criminality
• What are the four physiological studies?

  Lombroso, Sheldon, Brain Injuries and Disorders and Biochemical Explanations
• What did Lombroso argue?

  -criminals are a separate species between modern and primitive humans.

  -physical shape of head and face determined the 'born criminal
• What are stigmata?

  physical characteristics possessed by criminals
• What are atavistic characteristics?

  primitive features from an earlier stage of human development
• What did Lombroso base his theory on?

  data gathered from autopsies on convicted criminals
• What features fit Lombroso's theory?

  long arms, sloping forehead, dark skin, flat nose
• what did Lombroso say about Atavistic's ?

  they are unable to control impulses and had a reduced sensitivity to pain
• What stigmata did murderers have?

  bloodshot eyes and curly hair
• what stigmata did sex offenders have?

  thick lips and protruding ears
• What was Sheldon's theory?

  People could be classified into three body shapes, corresponding with three different personality types known as somatotypes.
• What are the three somatotypes?

  ectomorph, mesomorph, endomorph
• What are endomorphs?

  fat and soft - tends to be sociable and relaxed
• What are ectomorphs?

  thin and fragile - introverted and restrained
• What are mesomorphs?

  muscular and hard - tend to be aggressive and adventurous
• What did Sheldon find about criminals?

  many convicts were mesomorphic and they were least likely ectomorphic. Argued mesomorphs are more likely to engage in risk taking behavior which explains their tendency to commit crimes.
• Can brain damage make someone criminal?

  yes if there is damage or change to the pre-frontal cortex as it can change a persons behavior.
• What is the pre-frontal cortex responsible for?

  memory, self-control and decision making
• What diseases affect the pre-frontal cortex?

  dementia, brain tumor, Huntington's
• What happened to Phineas Gage?

  tampering rod went through his skull damaging his pre-frontal cortex. His personality changed and he became anti-social, bad mannered and often got into fights and assaults.
• What did Raine et el discover?

  1994 - used PET scams to study criminals brains - found that criminals were more likely to have a damaged pre-frontal cortex.
• What are bio-chemical explanations?

  criminality is due to chemical imbalances in the brain
• What are the 4 biochemical explanations?

  sex hormones, blood sugar levels, substance abuse and other substances (diet)
• What is the biochemical explanation surrounding sex hormones?

  males = over production of testosterone cause emotional and aggressive outbursts - link - rape& murder

  females = PMT, post-natal depression = partial defenses from women charged with crimes - loss of control
• What is the bio-chemical explanation surrounding blood sugar levels?

  hypo glycaemia can trigger aggressive reactions - link between low blood sugar and alcohol abuse . Drinking lowers blood pressure leading to aggressive behavior.
• What is the bio-chemical explanation surrounding substance abuse?

  involves taking drugs e.g. alcohol, MDMA and cocaine. Saunders argues alcohol plays a part in around 1000 arrests per day.
• What is the bio-chemical explanation surrounding other substances (diet)?

  food additives and diet can impact behavior e.g. vitamin B deficiency links to aggressive behavior.
• What was the biochemical factor in Christine English's case?

  murdered her boyfriend - got it reduced to manslaughter on the grounds of diminished responsibility - due to pre-menstrual tension
• What was the biochemical factor in Michael Young's case?

  killed his wife - argued testosterone injections turned him aggressive and he lost control
• What was the biochemical factor in Steven David Garcia's case?

  tried to kill his wife as he hit her w a hammer and ran her over with a van - court ruled low blood sugar can cause involuntary intoxication - new trial
• What was the biochemical factor in Brian Browning's case?

  stabbed his wife 15 times - blamed actions on the use of sleeping pills - said they had a significant effect on his mental state - 9 days after she wanted a divorce
• What was the biochemical factor in Dan White's case?

  assassinated the mayor - psychiatrist said his consumption of sugary foods e.g. twinkies led to diminished capacity - successful - got involuntary manslaughter
• What are genetic theories?

  criminality is inherited
• What are the three genetic studies?

  Twin studies, Adoption studies, XXY study
• What is the Twin study?

  focusing on MZ twins as they come from the same egg - if one is criminal, they should both show tendencies
• What are dizygotic twins?

  fraternal twins - share 50% of DNA
• What are monozygotic twins?

  identical twins - share 100% of DNA
• What is a concordance rate ?

  The probability that if one twin has a characteristic the other twin will also have it