Biological theories

• Physiological theories


  Theories that explain criminality based on biological factors
• Lombrosso's 'born criminal' theory

  Argued criminals are physically different to non criminals, people were born criminals and have distinctive physical features. Essentially criminals come from a more primitive stage of humans (atavistic), therefore they are unable to control their impulses and have reduced sensitivity to pain
• Lombrosso's findings


  • Studied the head and face details of thousands of criminals, (383 dead and 3839 alive), he concluded 40% of criminal acts could be accounted for by atavistic characteristics
  • Later recognised atavistic features alone did not cause criminality, their existence interacted with a person's social and physical environment
  • Identified 3 types of criminals: Born criminals- atavistic type, Insane criminals- suffering from mental illness, Criminaloids- a class of offender whose mental characteristic predisposed them to criminal behaviour in certain circumstances
• Sheldon's Somatotypes theory


  Endomorphs- rounded and soft bodies, lacking muscle or tone, Ectomorphs- thin and fragile, lack of fat and muscle, Mesomorphs- muscular and hard bodied, very little body fat, strong limbs, broad shoulders and narrow waist. Sheldon's theory is that your body type can link to what crime you are likely to commit
• Sheldon's theory


  • Endo- social, relaxed, comfortable, outgoing, Ecto- self conscious, fragile, inward looking, emotionally restrained and thoughtful, Meso- adventurous, sensation seeking, assertive, domineering and enjoy physical activity
  • Mesos are attracted to risk taking, their physique and assertiveness comes in useful when committing violent and aggressive acts
  • Ectos are least likely to commit a crime
• Genetic theories of crime


  Argue that criminals are born, caused by the genetic code that we inherit from our biological parents. This might explain why crime often runs in families
• Twin studies


  Compare monozygotic (identical) and dizygotic (non identical) twins to see if criminality is genetic. If criminality is genetic, you would expect that if one monozygotic twin engages in crime than the other one will do the same at some point
• Twin studies findings


  • Lange(1929): 10/13 MZ twins had both been in prison, 2/17 DZ twins had both been to prison
  • Christiansen(1977): 52% concordance between MZ, 22% concordance in DZ
  • Ishikawa & Raine: 44% concordance for MZ, 21.6% concordance for DZ
• Adoption studies


  Compare children to their biological and adopted parents (nature vs nurture)
• Adoption studies findings


  • Mednick et al studied 14000 adopted boys and their criminal record. 20% had a criminal record if their biological parents did. 14.7% if their adopted parents did. There is no correlation between number of criminal convictions between adoptive parents and their adoptive children but there was a significant link with biological parents
• Jacob's XYY Study


  Abnormalities of the sex chromosomes could be a cause of criminality. We normally have 46 in 23 pairs. XX is female. XY is male. There a variety of chromosome abnormalities, one of which being an extra Y chromosome (XYY)
• Jacob's XYY Study findings

  • Jacob et al (1965) claims men with XYY are more aggressive than XY men. Based on evidence that XYY men are over represented in the prison population (15 per 1000 in the prison population, 1 per 1000 in the general population). Jacob found many of the XYY men in prison has been convicted of violent crime
• Brain injuries and disorders

  Biological factors that could contribute to criminality
• Many of the XYY men in prison has been convicted of violent crime
• XYY syndrome


  • Evidence found an association between XXY and offenders for violent behaviour
  • Prince and Whatmore found links between XYY syndrome and property crime
• Even if some offenders do have the XYY syndrome this doesn't prove that it was the cause
• XXY males fit the stereotype of offenders and are more likely to be labelled such by courts, so they are more likely to go to prison
• XYY males may have been over represented in the prison population because they have a low IQ meaning they are more likely to be caught and will affect the skew of the prison population
• XYY syndrome is very rare only 1 in 1000 males have it so it can't explain much crime and only applies to certain offences
• XYY offers no explanation for female criminality
• Brain injuries


  Damage to the prefrontal cortex in the brains of the criminals, the part of the brain that controls impulsive behaviour
• Brain diseases


  Abnormal brainwave activity
• There are four different lobes of the brain. There are different functions associated with each lobe. Area in the frontal lobe called the prefrontal cortex seems to be important in monitoring and regulating our behaviour. Damage to this area could cause behavioural problems.
• The amygdala is an almond shaped structure in the limbic system. This area is important for the processing of emotions, particularly fear. It has been found that there are important differences in the activity in the left and right amygdala
• Brain injuries and disorders

  • Foetal alcohol syndrome, prenatal smoking, prenatal drinking, malnutrition
  • Phineas Gage
  • Charles Whitman
• Biochemical explanations


  The idea that biochemical substances and processes are a possible cause of criminal behaviour because of their effects on brain chemistry and mental processes
• Sex hormones


  Testosterone and oestrogen
• Testosterone


  Over production linked with crimes like rape and murder
• Levels peak between puberty and early 20's, this correlates with male crime rates
• Females


  PMT, postnatal depression and lactation have all been used as a partial defence for crimes ranging from infanticide to shop lifting. It was accepted that some of those hormones impaired the defendants judgement.
• Blood sugar levels


  Low blood sugar (hypoglycemia) can trigger aggressive reactions. The link between low blood sugar and alcohol abuse. Alcohol consumption is closely linked to crime and violence
• Substance abuse


  Abuse of some other substances such as cocaine and steroids correlate with violence
• Other substances


  • Low serotonin- aggression
  • Vitamin B deficiency- erratic and aggressive behaviour
  • Tartrazine- hyperactivity
• Biological theories are the idea that criminal behaviour is caused by biological factors such as genetics, brain structure and biochemistry
• Key findings of biological theories include links between genetics, brain abnormalities and biochemical imbalances and criminal behaviour
• General criticisms of biological theories include ignoring environmental factors, gender bias, and lack of evidence that biological factors directly cause crime
• Crime control policies refer to the laws, regulations and other governmental actions to reduce criminal acts. Public safety is a key responsibility of the government, policy makers are involved at a state and local level.
• Informal policy


  Encouraging/discouraging certain behaviour e.g police posting on social media
• Formal policy


  Crime control and state punishment e.g breathalyser and prison
• Eugenics


  The idea that genetic quality of a human population can be controlled through selective breeding, 'genetically unfit' people should be prevented from breeding