Jacobs XYY Flashcards
What do theorists speculate an additional ‘Y’ chromosome causes to a man?
It may hyper masculinise men.
What did Jacobs et al suggest about the additional Y chromosome?
That men were more aggressive and more likely to commit violent crimes.
What did Jacobs et al find?
That XYY men are over-represented in the prison population:
There are 15/1000 sufferers in prisons and 1/1000 in the general population.
What did Epps (1995) find that goes against Jacobs’ suggestions?
Epps found that XYY men tend to commit non-violent crime, not violent crime.
What did Graham et al (2007) find that goes against Jacobs’ suggestions?
That testosterone levels among XYY men are no different from XY men, therefore XYY men are no more aggressive.
However, they have an increased risk of developmental delay and learning difficulties.
What did Hollin (1992) find about criminal behaviour?
There is a small association between learning difficulties and criminal behaviour. IQ scores in convicted offenders are marginally lower than the general population.
What did Lund (1990) find about offender groups?
That there is a slightly higher prevalence of mild learning difficulties amongst offender groups.
Why might XYY men be over-represented in the prison population?
It may be a consequence of the learning difficulties associated with the condition.
What is one strength of Jacobs’ study?
It is supported by other research evidence.
Who’s research supports Jacobs’ study?
Blonigen et al (2005): Certain types of crime, like violent crime, is inherited; it seems that psychopathy can be inherited.
What is one weakness of Jacobs’ study?
It does not explain all types of crime because some crime like non-violent crime (fraud, theft, bigamy) is not inherited.
Who conducted research in 1995?
Epps.
Who conducted research in 2007?
Graham et al.
Who conducted research in 1992?
Hollin.
Who conducted research in 1990?
Lund.
