Physiological theories

• Lombroso's theory


  Criminals looked physically different, are a separate sub-species of human and are 'atavistic'- less developed by humans
• Lombrosos experiment

  Examined facial and cranial features of 383 des and 3839 living, finding 40% of criminal acts had atavistic features
• Atavistic features

  > criminals: strong,prominent jaw, high cheekbones, dark skin, extra toes/nipples or finger, sunken eyes

  
  

  > murderers: bloodshot eyes, curly hair and long ears

  
  

  > sexual deviants: glinting eyes, swollen fleshy lips

  
  

  > Fraudster: thin and reedy lips

  
  

  > other non-physical traits: unemployment, tattoos and use of criminal slang.
• Lombroso's strengths

  Used objective, scientific methods
• Lombroso's weaknesses

  - didn't include control group on non-criminals and only used Italians

  - Charles Goring replicated this study with control group and found no effect
• Sheldon's somatotypes

  Criminals had certain body ybtypes
• Sheldon's experiment

  Took meticulous examination of photos of 4000 scantily clothed men with font, side, back views
• Ectomorph


  Thin, fragile, introverted, restrained, sensitive
• Mesomorph


  Muscular, hard, aggressive, dominant, adventurous, CRIMINAL
• Endomorph


  Fat, soft, sociable, relaxed, peaceful
• Sheldon's strength

  -gluck gluck found that 60% of criminals were mesomorphs
• Sheldon's weaknesses

  -people's bodies change throughout lives, not fixed

  -doesn't account for ectomorphs or endomorphs being criminals
• Jacob's XYY theory

  Males have extra Y chromosomes = super male syndrome, who are more aggressive, violent, explosive, hyperactive
• XYY experiment

  Found studies of imprisoned criminals in psychiatric hospitals that XYY men are over represented in prison

  15 in 1000 men have the condition in prison, compared to normally 1 in 1000

  15x more likely
• XYY case study

  -John Wayne Gacy

  -sexually assaulted, tortured, murdered at least 33 men/children
• XYY strengths

  -Prince + whitmore found XYY males generally less mature and more unstable than normal, with tendency to commit property crime

  - higher average proportion of XYY males among prisoners- 15x
• XYY weaknesses

  -not all with XYY syndrome commit crime

  -doesn't account for why women commit crime
• twin studies

  show the nature debate- crime can be genetic. MZ twins share 100% DNA and DZ twins share 50% DNA
• Christiansen twin study

  studied 4000 danish twins and found concordance rates of: MZ=F-2%, M-35%. DZ=F-2%, M-13%
• Johannes Lange twin study

  investigated 13 MZ twins and 17 DZ twins, found 10/13 MZ twins both served time in prison and 2/17 DZ twins both served time in prison
• Adoption studies

  argue nurture debate- if similar to genetic parents=nature, if similar to adoptive parents=nurture
• Hutchings and Mednick adoption study

  studied 4000 adopted children and found high proportion of boys with criminal convictions also had biological parents with convictions
• Twin + adoption studies strengths

  -Adler found aggressive and violent behaviours are at least partly caused by genetics

  -studies are useful to separate genetic and environmental causes of crime
• Twin + adoption studies weaknesses

  -parents treat MZ twins more alike than DZ twins, meaning they feel closer to each other and more influenced

  -adoptive children are often placed in environments similar to birthplace
• brain injuries

  rare cases of brain injuries cause criminality, like Phineas Gage
• brain diseases

  brain tumours and lesions linked with deviant behaviours -impacts abilities of the brain to regulate behaviours
• Raine PET scans

  damage to the pre-frontal cortex found in criminals, which showed reduced brain activity, responsible for impulsive behaviour
• brain injuries and disorders strengths

  -in a few extreme cases, brain injury of disease has led to major changes in an individual's behaviour and personality, including criminality

  -prisoners are more likely than non-prisoners to have a brain injury
• brain injuries and disorders weaknesses

  -crimes caused by brain injury or brain disease are rare. The sufferer's original personality is more important in whether they engage in crime

  -prisoners' higher likelihood of brain injury could be a result of their criminality (e.g. getting into fights) rather than the cause of it
• sex hormones-crime

  high levels of testosterone linked to criminality
• blood sugar levels

  low blood sugar levels can lead to aggression
• substance abuse

  -cocaine and alcohol linked to violent behaviours

  -food colourings like tartrazine link to hyperactivity
• biochemical strengths

  -testosterone levels and male offending both peak at same ages

  -all factors affect mood, judgement and aggression
• biochemical weaknesses

  some research found aggression not greatly affected by testosterone levels