biological theories Flashcards
what are the three genetic biological theories of crime?
jacobs XYY
twin studies
adoption studies
what is Jacobs XYY about?
chromosomal abnormality
how many new borns have XYY
1/1000
how many more likely is someone with XYY likely to be in prison population
10x more likely
why are men with an XYY chromosome more likely to be found in a prison population?
because the extra Y chromosome makes them more masculine , so they produce more testosterone
Jacob et al found what to support his theory
a link between aggression to violent behaviour
what is another strength of Jacobs XYY study?
we can see they are more represented in the prison population.
what did Jacobs XYY study not look at, which is a limitation
didn’t look at psychological , environmental and social factors
who found that XYY men were not linked to agression
Thielgaard
what did Theilgaard find that is a limitation of Jacob’s XYY study?
that XYY men were not linked to aggression
what year did Theilgaard discover there was no link
1984
what are the two types of twins in twin studies?
monozygotic that come from one egg and dizygotic which comes from two eggs
what is controlled in twin studies
the environment as they are equal
who tested on 30 same sex twins
lange
how many MZ twins were in langes study
13
how many DZ were there in Lange’s study ?
17
how many MZ twins were both criminal ?
10/13
how many of the DZ twins were both criminal?
2/17
what does the statistic of twin studies shown?
crime is genetic and it is hereditary
