AC 2.1- biological theories- genetic theories

Question 1

what did jacobs suggest (2)

Answer 1

-chromosomal abnormalities in men are linked with criminality
-abnormalities occur when a man receives an extra Y chromosome so there are 47 instead of 46

Question 2

jacobs: study- XYY syndrome (2)

Answer 2

-compared rate of XYY in imprisoned criminals vs general population
-XYY is over represented in prison populations (9 in 315) vs general population (1 in 1000)

Question 3

jacobs: evaluation- strength

Answer 3

-association between XYY and violent prisoners

Question 4

jacobs: evaluation- 2 limitations

Answer 4

-labelling- XYY males fit typical offender stereotype- more likely to be sentenced
-XYY males over represented in prison due to low intelligence (skewed prison samply)- more likely to get caught

Question 5

what did mednick suggest

Answer 5

link between biological parents+children , even if child is later adopted

Question 6

mednick: study- adoption studies (2)

Answer 6

-studied concordance rate (CR) between birth parents and 14,000 adopted sons
-findings:
adopted sons more likely to be criminal if birth parents are criminal (20% CR)
adopted sons less likely to be criminal if adoptive parents are criminal (14.7 CR)

Question 7

mednick: evaluation- 2 strengths

Answer 7

-overcomes problem faced by twin studies- monozygotic twins bought up in same house makes it impossible to separated influence of genes from environment
-good sample size

Question 8

mednick: evaluation- 2 limitations

Answer 8

-many children not adopted straight after birth-stay with biological parents for awhile- this early time can lead to criminality
-adopted children usually put in similar environments to birth family (ethnicity, class location)- similar environment=similar behaviour

Question 9

what did christiansen suggest (2)

Answer 9

genetic link between criminality in twins
-monozygotic and dizygotic twins have different levels of criminality

Question 10

christiansen: study- twin study (2)

Answer 10

• studied over 3000 pairs of MZ and DZ twins to determine genetic explanations for criminality
  -findings: male MZ= 35% CR, male DZ= 13% CR

Question 11

christiansen: evaluation- 2 strengths

Answer 11

-logical to examine a link between offending behaviour and MZ twins
-research support (Raine) from a longitudinal study- MZ twins= 45% CR, DZ twins- 21.6% CR

Question 12

christiansen: evaluation- 2 limitations

Answer 12

-if criminality was only genetic, MZ twins would have 100% CR
-higher CR for MZ twins can be due to sharing a home- shared environments= similar behaviour

Question 13

jacobs: features of XYY males (2)

Answer 13

-display tendencies towards aggression and violence
-have lower intelligence, are very tall and well built