Jacobs XYY Flashcards
What is XYY syndrome?
XYY syndrome is when a male is born with an extra Y chromosome
What is Jacobs XYY theory?
That people with XYY syndrome are more likely to become criminal and be violent.
What are some characteristics of XYY syndrome?
Increased Testosterone
Longer Limbs
Severe Acne
Behavioural issues
Lower IQ
Likely to have a learning disability
Who was studied during Jacobs study?
197 prisoners, they were studied for chromosomal abnormalities.
What did the study suggest?
That men with XYY syndrome were more aggressive and potentially violent than the normal XY male.
What else did Jacobs discover about XYY syndrome?
That males with XYY syndrome are over-represented in the prison population.
Every 1000 prisoners 15 have XYY syndrome opposed to every 1000 in the general population there is 1 person that has it.
What else did Jacobs discover about XYY syndrome?
That males with XYY syndrome are over-represented in the prison population.
Every 1000 prisoners 15 have XYY syndrome opposed to every 1000 in the general population there is 1 person that has it.
What are some limitations of the study?
It was biased - it was only conducted in prisons and mental institutions.
There is also no proven link between having an extra Y chromosome and criminal behaviour.
Case study for Jacobs XYY?
John Wayne Gacy
Committed 33 murders, maybe more.
Started assaulting boys and was convicted after beating one. He served 18 months in prison for this.
Enjoyed dressing as a clown when killing.
His aggressive behaviour could be linked to XYY syndrome.
Some strengths of XYY?
Other studies have supported Jacobs claims.
The methodology in Jacobs study is very scientific we she used DNA analysis, which makes it more reliable.
Knowledge of XYY syndrome means it can be identified earlier in life, and help those with it.
Some weaknesses?
