Biological theories of crime Flashcards
what are the biological theories of crime
- Jacob XYY
- twin
- adoption
- Sheldon
- Lombroso
what are the genetic biological theories
- Jacob XYY
- twin
- adoption
what are the physiological biological theories
- Lombroso
- Sheldon
what was the aim of Jacob XYY study
to see if men with a chromosome abnormality of an extra Y chromosome commit more crime
what were Jacob XYY results/statistics
XY men were 10x more likely to be found in criminal populations
how this theory is linked to criminal behaviour-xyy
an extra Y hyper-masculine’s men and causes them to be more aggressive so they commit more violent crime
how is this theory criticised(XYY)
- later studies found they tend to commit non-violent crime
- need to take other factors into account
- not all XYY men are aggressive and criminals and some criminals are not XYY men
examples of XYY man
serial killer John Wayne Gacy said to have XYY and sexually assaulted and killed around 33 men in USA
what was the aim of twin studies
studied monozygotic and dizygotic twins to see the impact of genetics on criminality
who took out the twin study
Lange
when was the twin study
1929
what was the twin study
studied 30 pairs of twins and at least one was criminal
what were the findings of the twin study
- 10 out of 13 MZ twins were both criminal and only 1 out of 17 DZ
- chance of one twin taking part in crime when the other twin was criminal was 50% in MZ and 20% in DZ
how can this theory be criticised(twin)
- difficult to separate influence of social factors
- small and old sample so not valid or reliable
- could be nurture
who took out the adoption study
hutchings and mendrick
what was the aim of adoption study
aimed to separate impact of environment(adopted parents) from the influence of inheritance(biological parents)
what was the adoption study
studied 14,000 adopted children and found a high amount of boys with criminal convictions had biological parents with criminal convictions
what were the findings of the adoption study
adoptee with criminal parents were more likely to take part in property crime and is stronger in boys
how can this theory be criticised(adoption)
- not all children with criminal parents are criminals as adopted parents can have a positive impact
- depends on the age they were adopted
what was Sheldon’s theory
believed criminal behaviour linked to a persons physical form and that there are 3 types of body shapes that correspond with 3 different personality types
what were the 3 body types in Sheldon theory
- endomorphic
- ectomorphic
- mesomorphic
what did Sheldon find
criminals were more likely to be mesomorphic
what was endomorphic
fat, soft= sociable, relaxed
what was ectomorphic
thin, fragile= self conscious, introverted
what was mesomorphic
muscular, hard= adventurous, aggressive
how can this theory be criticised(Sheldon)
- cannot assume all mesomorphs are criminals
- people may change their physical form
what was Lombroso’s theory
argued a born criminal can be determined by their looks
what word did Lombroso use to describe criminal features
atavistic features
what were these criminal features
large jaws, big ears, big nose, monobrows, long chins
what was Lombroso’s study
compared Italian prisoners and Italian soldiers and said they were physically different
how can this theory be criticised(Lombroso)
- too simplistic as many other factors can affect crime
- criticised for racism
