BIOLOGICAL THEORIES
Physiological
Genetic
Brain injuries and disorders
Biochemical explanations
Adoption Studies
Lombroso's theory
Sheldon's somatotypes theory
Endomorphs=
Looks= rounded, soft, fat, lack muscle or tone and wide hips.
Personality= sociable, relaxed, comfortable and outgoing.
Ectomorphs=
Looks= thin, fragile, lack fat and muscle, flat chested, narrow hips and shoulders, thin face and high forehead.
Personality= self conscious, fragile, inward looking, emotionally restrained and thoughtful.
Mesomorphs=
Looks= muscular, hard bodied, little fat, strong limbs, broad shoulders, narrow waist.
Personality= Adventurous, sensation seeking, assertive, domineering and enjoy physical activity.
Measured and recorded details of the heads and faces of prisoners.
Conclusion= criminals could be identified by their distinctive facial features e.g. large jaw, high cheek bones, long arms, large eye sockets, etc.
Conclusion= Mesomorphs are most likely to engage in crime. They are more likely to be attracted the the risk-taking involved and their physique can play and important role in committing a crime.
Atavism= pre-social, unable to control impulses and reduced sensitivity to pain. 'savages'
Jacob XYY study
Twin studies
Monozygotic (identical twins)= share 100% of genes
Dizygotic (non-identical)= share 50% of genes
Christiansen's study-
3,586 twin pairs in Denmark.
MZ twins= 52% concordance rate.
DZ twins= 22% concordance rate.
Mednick et al- 14,000 adopted sons in Denmark.
Birth parent= 20% concordance rate.
Adoptive parent= 14.7% concordance rate.
If one member has 'criminal genes' it is likely that their blood relatives will have them too.
Compares adopted children to both their biological parents and adoptive parents. (Nature v nurture)
Conclusion= More likely to have a criminal record if a birth parent also had a record. This supports a genetic explanation.
Conclusion= If one twin is criminal the other ought to be criminal too- more common with monozygotic twins.
We normally have 46 chromosomes arranged in 23 pairs (half of each pair from each parent).
One pair consists of sex chromosomes and determines whether we are male or female.
XX= female.
XY= male.
Jacob et al-
XYY= 'super male syndrome'.
Tend to be very tall, well built, low intelligence, more aggressive and potentially violent than other males, immature, unstable and strong tendency to commit seemingly motiveless property crimes.
psychiatric hospital study- higher than average proportion of inmates were found to have XYY syndrome.
Conclusion= Those with XYY syndrome are more likely to commit crimes.
Brain Injuries
Diseases
Phineas Gage- personality changed after a major brain injury.
Studies have found that prisoners are more likely than non prisoners to have suffered brain injuries.
Encephalitis lethargica- linked to destructiveness, impulsiveness, arson and abnormal sexual behaviour.
Senile dementia, Huntington's chorea and brain tumours- various forms of deviant or anti-social behaviour.
Brain diseases have been linked with criminal or anti-social behaviour.
Brain injuries have been identified as a cause of criminality in a few rare cases.
Sex hormones
Blood sugar levels
Substance abuse
Males- Overproduction or underproduction of hormones can cause emotional disturbances that lead to criminal behaviour.
Testosterone has been linked with crimes such as murder or rape.
Females- Pre-menstrual tension, post-natal depression and lactation have been accepted as partial defences for women charged with crimes.
Hypoglycaemia (low blood sugar) can trigger aggressive reactions. Drinking large quantities of alcohol can induce hypoglycaemia.
E.g. drugs, alcohol, food additives and diet, allergens, vitamin deficiencies and lead pollution