XYY theory

Question 1

what is the theory

Answer 1

genetic
biological

Question 2

what does the theory state

Answer 2

men with an extra Y chromosome are more aggressive and more inclined to be violent

Question 3

how can you test for the extra Y chromosome

Answer 3

blood tests

Question 4

what are men called who have an extra chromosome

Answer 4

supermales, the have more testosterone- this isn’t inherited

Question 5

what was jacob et als AIM

Answer 5

to identify whether XYY links to criminality

Question 6

what was jacob et als PROCEDURE

Answer 6

• blood tests for 315 inmates to identify if they had the extra chromosome
• in scottish maximum security psychartric hospital, inmates where described as ‘mentally subnormal’
• compared this to the general population

Question 7

what where jacob et als FINDINGS

Answer 7

• 1 in 28 had XYY in prisons
• 1 in 1000 in general population

Question 8

what was jacob et als CONCUSION

Answer 8

suggests that XYY could be linked to increased violence or anti social behaviour due to more testosterone said to be pre dispositions of crime

Question 9

describe john wayne gacy

Answer 9

• toured and murdered at least 33 young men and boys
• known as killer clown due to public appearances as a clown
• had XYY condition
• stored his victims corpses under his bed for up to 24 hours before moving them to a crawl space
• tricked them to come to his house by saying he was doing a magic trick
• someone he assaulted reported him to the police, this got him caught

Question 10

STRENGTH: how is jacob et als study a strength, two links to GRAVE

Answer 10

he found there was an over representation of XYY men in prisons then in wider society
generalisable: used a large sample
reliable: scientific method and repeatable

Question 11

STRENGTH: what did alder et al indicate

Answer 11

that aggressive and violent behaviour is partly determined by genetic factors
john wayne gacy and arthur shawcross are both rel life examples
therefore it has beee supported by other study’s and other case study

Question 12

STRENGTH: what did price and whatmore find link to GRAVE

Answer 12

some links between the syndrome and property crime
applicable: useful to society for police when investigating property crime

Question 13

WEAKNESS: how could jacob et als study be criticised, link to GRAVE

Answer 13

it’s low in generalisability as it’s only on males in a psychiatric hospital therefore it’s biased and cannot be generalised to females/non binary or mainstream prisons

Question 14

WEAKNESS: how does theilgaard criticise the theory

Answer 14

he found that the characteristic of aggression wasn’t associated with XYY mean although some study’s have supported the theory not all have

Question 15

WEAKNESS: why can it not explain much about crime

Answer 15

the syndrome is very rare and even if some offender have XYY this could be a coincidence as it doesn’t account for social factors that may cause violence