biological theories of crime Flashcards
what 4 biologocal theories are there
-lombrosos atavistic features
-sheldons somatotypes
- xxy theory
-twin/adoption studies
what did lombroso believe
that people are criminal and you can identify them from their features
what are some examples of atavistic features
- strong jaw
- heavy eyebrows
- thick lips
-large ears
-bloodshot eyes
-curly hair
what was lombroso’s research
he studied the facial fatures of 383 dead criminals and 3839 living criminals
he concluded that 40% of criminals had atavistic features
what number of features did men and women need to have to be classed as criminals
women = 3 +
men = 5 +
what did sheldon believe
he believed that criminal behaviour was linked to a persons physique
what 3 types of somatotypes aare there
- endomorph
- ectomorph
- mesomorph
what is an endomorph
they have a round phsique and are soft and fat and have difficulty losing weight
what is an ectomorph
they are thin and fragile
what is a mesomorph
they are muscular and athletic people
which somatotype is most lokely to be criminal
mesomorph
what was sheldons research
he rated 200 students and 200 criminals and found that crimals had the highest rates of mesomorph body types
what is the XYY theory
where a man has an extrax Y chromosome because of a random error occuring in the sperm formation whilst making him
what did jacobs find in her research
she exmained 198 scottish prisoners and using the karyotyping methods she found thst 3.5% of the prison population had the XYY syndrome compared to only 1% had it in the scottish general population
what case study is linked to the XYY theory
john wayne gacy- he was a serial killer who killed over 30 young men. he had the extra y chromosome
why do we use twin studies
to compare genetic and environmental influences, identical twins share 100% of the same dna so we use them to see if the would act the same in situations
what is a concordance rate
the chance that 2 people share the same characteristic, traits or behaviours if one of them is exhibiting a behaviour
what is the supporting research for the twin studies
christiansen studied 3586 twins in denmark, he found that monozigotic twins had 52% concordance rate between them if one was a convicted criminal whereas dizigotic twins had a lower ate of 22%
why do we use the adoption studies
to see if environmental factors influence criminals
what is the supporting research for adoption studies
hutchings and mednick-found a higher percentage of adopted boys with criminal covictiond had biological parents with criminal convictions to
mednick et al- repeated the study with 4000 adopted Danish men and found no significant relationship between criminal convictions of adoptive parents and their adopted children, but a significant correlation between the number of criminal convictions of the biological parents and their offspring.
