AC 2.1 Flashcards
(86 cards)
what are the 3 genetic theories of criminality?
twin studies
adoption studies
XYY theory
what is the XYY theory?
this theory suggests some crime might be attributable to chromosomal abnormality
what chromosomes do humans usually have?
they usually have 46 chromosomes, 2 of which determine sex: XX = female XY = male
what does the XYY condition involve?
an extra Y chromosome
what and when did Jacob et al say about XYY men?
they have been called supermales and it is suggested they are more aggressive and more inclined to be violent than other males (1968)
what is the proportion of XYY males in prison compared to in the general population?
15/1000 sufferers in prison
1/1000 sufferers in population
how does serial killer John Wayne Gacy link to XYY syndrome?
it is said that he had it and as a result he sexually assaulted, tortured and killed at least 33 men in the USA
what do twin studies suggest?
they support the contention that a heritable trait may increase risk for criminal behaviour
what is MZ
DZ
concordance rate?
monozygotic twins = identical
dizygotic twins = non-identical
concordance = when both twins share a characteristic
what did Johannes Lange study in 1929? Twins
he studied twins and found that MZ twins showed a higher concordance rate than DZ criminal behaviour
what did Johannes Lange find in 1929? Twins
10/13 MZ twins both served time in prison but 2/17 twins had such concordance
what did Christiansen study in 1977?
3586 twins from Danish islands
what did Christiansen find in 1977?
concordance rates of 35% for MZ male twins and 13% for DZ male twins
concordance rates of 21% for MZ female twins and 8% for DZ female twins
what are adoption studies?
the comparison of criminals with both their biological and adoptive parents; it considers nature v nurture
when may a genetic basis of criminality be suggested?
if in criminal behaviour the child is more similar to their biological parents
what did Huthchings and Mednick study in 1975?
14,000 adopted children
what did Huthchings and Mednick find in 1975?
a high proportion of boys with criminal convictions had biological parents with criminal convictions too, suggesting a link between aggression and genetics
what did Mednick et al find in 1994?
no relationship between the number of criminal convictions of adoptive parents and their adopted children, but did find a significant correlation between the number of criminal convictions of the biological parents and their offspring
what are the 2 main physiological theories of criminality?
Lombroso
Sheldon
who was Lombroso?
Italian psychiatrist and military doctor who developed theories about criminals, he was the father of modern criminology
what did Lombroso argue?
the criminal was a separate species and a ‘born criminal’ could be determined by the shape of a head
what did Lombroso claim?
criminality was heritable and those who were, had atavistic or primitive features
what were the atavistic features Lombroso claimed criminals had?
large or forward projection of the jaw
high cheekbones
flattened or upturned nose
low sloping forehead
long arms relative to lower limbs
large ears
what does atavistic mean?
relating to something ancient or ancestral