unit 2 biological theories of criminality - genetic theories

Question 1

what is the twin study key idea?

Answer 1

if crime is genetic - identical (Mz) twins should have identical criminality

Question 2

what are twin study findings?

Answer 2

christiansen: concordance in criminality Mz = 52% vs Dz = 22%

Question 3

what is the adoption key idea?

Answer 3

adoptees share environment of adoptive parents/genes of biological parents. if genetic, criminality will match biological parents more.

Question 4

what are the adoption study findings?

Answer 4

mednick et al: birth parent concordance = 20% vs adopted parent concordance = 14.7%

Question 5

what are 3 strengths?

Answer 5

twin and adoption studies give some support to genetic explanations, adoption studies overcome the problem of isolating genes and environment, research design of adoption studies is logical (nature vs nurture)

Question 6

what are 3 limitations?

Answer 6

if criminality was only genetic MZ twins would have 100% concordance, it is impossible to isolate genetic effects fully from environmental ones, adopted children often placed with similar families to their birth family.

Question 7

what is jacob’s xyy study’s key idea?

Answer 7

XYY syndrome in males makes them genetically predisposed to criminality

Question 8

what was his study?

Answer 8

compared rate of XYY in imprisoned criminals with general population

Question 9

what was his findings?

Answer 9

higher than average proportion of inmates had XYY

Question 10

what were the features of XYY?

Answer 10

very tall, well-built, low intelligence, high aggression, violent.

Question 11

what are 2 strengths of jacob’s XYY study?

Answer 11

jacob et al found association with XXY and violent prisoners, price and watmore found links with XYY and property crime

Question 12

what are 4 limitations?

Answer 12

having the syndrome doesn’t mean that it is the cause of crime, XXY men fit stereotype of violent offenders - labelling theory, low intelligence of XYY may give higher chance of being caught, syndrome is too rare to explain much crime

Question 13

what is monozygotic?

Answer 13

identical twins that share 100% of the same genes

Question 14

what is dizygotic?

Answer 14

non-identical twins that share only 50% of the same genes (like ordinary siblings)

Question 15

what is a chromosome?

Answer 15

made from DN and protein. carry genetic information we inherit from our parents. most people have 23 pairs.

Question 16

what is a super-male?

Answer 16

another term for XYY syndrome. those affected carry an extra Y (male) chromosome on one of their 23 pairs.