AC2.1: Describe Biological theories of Criminality
Physiological theories - Lombrosso
- Father of Modern Criminology (1835-1909)
- Criminals are a separate species, between modern + primitive, clear differences
between offenders + non-offenders
- ‘Born Criminal’, determined by physical shape of head + face
- Criminality heritable, had atavistic or primitive features
● Atavistic - relating to something ancient or ancestral
● Examples: large or forward projection of jaw, high cheekbones, large ears,
asymmetric face, long arms relative to lower limbs, etc
- E.g. ‘throwbacks’, to earlier stage of human development that manifested into
criminal tendencies to commit crime
- Examined facial + cranial features of 383 dead + 3839 living criminals - concluded
40% of criminal acts could be accounted for by atavistic features
- Different criminals had distinct looks; murderers had bloodshot eyes + curly hair, sex
offenders has thick lips + protruding ears
- Not just physical traits - other aspects of born criminals
● Includes insensitivity to pain, use of criminal slang, tattoos, unemployment
- Chinese Uni study supports idea, ID photos of 1856 Chinese men, half with previous
convictions, entered in AI programme, found it wrongly flagged innocent men as
criminals 6% of the time, but correctly identified 83% of real criminals
Physiological theories - Sheldon
- Shares Lombrosso’s principle, criminal behaviour linked to physical form
- Examined photos from front, back + side views of 4000 scantily clad men, put forward
3 fundamental body types - somatotypes
● Endomorphic - fat, soft, tend to be sociable + relaxed
● Ectomorphic - thin + fragile, introverted + restrained
● Mesomorphic - muscular + hard, more aggressive + adventurous
- Found many criminals prone to violence + aggressive acts, mesomorphic, less likely
was ectomorphic
- Used sample of college students + delinquents, rated on scale of 1 to 7 (1 being low) on
their resemblance to mesomorphy
- Delinquents, higher than average for mesomorphy rating than college students
- Mesomorphic, more likely to be attracted to risk taking, involves their physique +
assertiveness, assets to crime
Physiological theories - Brain abnormalities
- Studies suggest damage to prefrontal cortex of brain may cause individuals to have an
altered behaviour pattern - more immature, increases loss of self control, inability to
modify behaviour
, - Raine et al (1994) used PET scans to study living brains of impulsive killers, damage
found in prefrontal cortex, part of brain that controls impulsive behaviour
- E.g. Phineas Gage:
● Railroad worker, survived accident where a large iron rod went through his head,
destroyed much of frontal lobe
● Personality + behaviour affected: extravagant + antisocial, bad language, bad
manners, liar
● Part of brain lost associated with mental + emotional functions that had changed
● Doctor believed, balance between his intellectual faculties + animalistic
behaviour destroyed in accident
Physiological theories - Neurochemical
- Brain’s chemistry, influenced by diet (food, additives, pollution or hypoglycaemia - low
blood pressure linked with diabetes)
- Low levels of serotonin linked with higher aggression
● Regulates signals between neurons + said to control moods
- Large amounts of steroids, can lead to extreme violence (‘roid rage’)
- Steroids increase testosterone levels + muscle growth
- E.g. Horace Williams, American bodybuilder, beat a man to death after taking 2000x the
recommended dose of steroids
Genetic theories - XXY theory
- Suggest crime may be due to chromosomal abnormality
- Chromosome structure in cell nuclei, humans have 46 chromosomes, 44 determine
shape + constitution of body, 2 determine sex
- XX is female, XY is male
- ‘XYY’, extra Y chromosome
- XYY men, ‘supermales’, suggested to be more aggressive, more violent than average
male
- Jacob et al (1965), men with XYY syndrome, more aggressive than normal men
- Other studies show, XYY men are overpopulated in prisons, 15 in 1000 in prison, 1 in
1000 in general population
- Serial killer, John Wayne Gacy had XYY syndrome, sexually assaulted + murdered 33
men
- Claim that XYY syndrome can lead to violent crimes, comes from studies of imprisoned
criminals, high proportion of inmates found to have XYY chromosome
Genetic theories - Twin studies
- Supports the idea that a heritable trait may increase risk for criminal behaviour (nature)
- Identical twins are monozygotic, one fertilised egg, share 100% of DNA, fraternal twins
are dizygotic, 2 separate fertilised egg, share 50% of DNA
- One twin is criminal, other might be too
- Christiansen (1977), studied 3568 tin pair in Denmark, 52% concordance rate between
MZ twins where one had a conviction, DZ itwins had a 22% chance
