AC 2.1 - biological Flashcards
Physiological theories - Lombroso
Focuses on the idea that physical characteristics make someone more likely to commit crimes.
This approach argues that people are born criminals.
In 1876 he argued that criminals are a separate species to other human beings.
He used evidence from autopsies of convicted criminals to determine that the shape of someone head and their face determined if someone would be criminal.
He believed that crime was innate and inherited.
Characteristics linked to criminality:
- long arms
- large teeth
- ears lacking lobes
- lots of body hair
- being left handed
He even had features for specific crimes:
- Murderers ~ bloodshot eyes and curly hair
- Sex offender ~ thick lips and protruding eyes
He examined 383 facial/cranium features and he studied 3839 photos of criminals.
Research support
- China put 1856 Chinese men’s photos into an AI
- half of these men were convicted criminals
- it wrongly flagged 6% to be criminal
- but it correctly identified 83% of the real criminals.
Physiological theories - William Sheldon’s body types
Used body measurement technique to connect body type with personality.
He came up with 3 main basic body types and found their associated personality/temperament.
He analysed 4000 body types.
Endomorphic
- Wide hips, narrow shoulders
- pear shaped
- lots of fat on body
- fat on upper arms
- slim wrists and ankles
- sociable, relaxed, comfortable, outgoing
Mesomorphic
- broad shoulders
- narrow hips
- muscular body
- strong forearms and thighs
- very little body fat
- adventurous, sensation seeking, assertive, domineering, enjoy physical activities
Ectomorphic
- narrow shoulders and hips
- thin face
- thin, narrow chest and abdomen
- thin legs and arms
- very little muscle or body fat
- self conscious, fragile, inward looking, emotionally restrained, thoughtful
Mesomorphs are most likely to be criminals.
The least likely to be criminals are ectomorphs.
Genetic theories - XYY theory
Caused by the presence of an extra Y chromosome.
Symptoms associated with it are learning disabilities and behavioural issues e.g., impulsivity.
Behaviours displayed include explosive temper, hyperactivity, lack of empathy and sometimes antisocial behaviour.
Testosterone makes people more aggressive so having the extra Y chromosome means that these super males are more aggressive and violent.
15 in 100 men in prison have XYY.
1 in 1000 men in the general population have XYY.
Genetic theories - Twin studies
Monozygotic = Born from one egg and share 100% DNA
Dizygotic = Born from 2 separate eggs and share 50% DNA
Concordance rate = the probability that if one twin has a characteristic, the other twin will have the same characteristic.
Lange 1929
- Investigated 13 MZ twins and 17 DZ twins.
- found that 10-13 MZ twins both served time in prison.
- found that only 2/17 DZ twins both served time in prison.
Christiansen 1977
- Investigated 3586 twin pairs born in the east between 1881-1910.
- concordance rates were as followed :
- male MZ = 35%
- female MZ = 21%
- male DZ = 13%
- female DZ = 8%
Genetic theories - adoption studies
These studies are to compare adopted children to the biological birth parents and adopted parents.
They do these studies because adopted children don’t group up in the same environment as their biological parents so they can see whether genetics or environment have a larger impact on crime
Mednick (1975)
- examined data from over 14,000 adopted sons in Denmark
- Found sons were more likely to have a criminal record if a birth parent also had a criminal record.
- A smaller percentage had a record if their adopted parents also had a record
- concludes that genetics play a bigger role in the development of criminal behaviour rather than environment
Brain injuries and disorders - examples of case studies
Charles Whitman
- killed 17 people in total and injured 31
- killed his mother and wife
- went to the university of Texas and shot a further 15 people
- he was shot dead by the police
- they found that he had visited several doctors before and they had prescribed him various medications
- his autopsy also showed that he had a tumour on his brain
Raine et al
- used PET scans to produce 3D images of the brain.
- found that criminals were more likely to have damage to the prefrontal cortex
Phineas Gage
- Had a thick iron rod go through his head (up through his cheek and out the top of his head)
- he survived but had damage to his prefrontal cortex
- this caused major changes in his personality
- he became very aggressive and violent, swore a lot, had mad manner and was very antisocial.
Biochemical explanations
Serotonin
- a neurotransmitter that is associated with regulating mood and behaviour
- has been doing that low levels of serotonin are associated with higher levels of aggression which may lead to criminality
Sex hormones
- Testosterone is associated with higher levels of violence and aggression.
- PMT, post natal depression and lactation have all been recognised as factors that affect women level of criminality, these factors can affect a persons mood or self control.
Blood sugar levels
- there are links between low blood sugar levels and the triggering of aggression levels
- low blood sugar levels are also linked with alcohol abuse which causes violence
Substance abuse
- involves the intake of drugs and other substances
- alcohol plays a role in around 1000 arrests per day
- estimated that 80% of family violence involves alcohol
- Cocaine and crack are linked to violence
- Heroin, cannabis and MDMA are linked with lowering aggression levels
Diet
- includes food additives, vitamins, allergens and lead pollution
- they affect different biochemical processes in the body and may affect behaviour
- lead and synthetic food colouring are linked with hyperactivity which may lead to criminality.
- vitamin B has been linked to erratic and aggressive behaviour
