Twin Studies

Question 1

Why is the theory being natural a strength

Answer 1

Biologically relationships between the twins is naturally occurring and researches do not manaiulate the variables and have high exokogical validity

Question 2

Supporting evidence a strength

Answer 2

Christianes study found concordance rate of 52 in MZ twins compare to 22% in DZ twins and results have been replicated by ishikawa and raine

Question 3

Difficult to separate genetic factors and environmental factors a weakness

Answer 3

MZ twins have same genetics but also brought up in same environment but means crime can be related to nurture rather than gentics

Question 4

Theory not being conclusive a weakness

Answer 4

If genetics were sole cause the concordance rate between mz twins would be 100% but only shows rate of 35% which lie

Question 5

Theory being methodologically flawed a weakness

Answer 5

Christian had small sample size which limit generalisation to findings of twins studies

Question 6

what is this theory??

Answer 6

genetic

Question 7

explain the biology of the theory??

Answer 7

• the nervous system is the organ that determines our behaviour
• structure and function of nervous system determines how we learn from and respond to our environment
• genetic inheritance determines structure and function of our nervous system which means our genetic inheritance causes behaviour
  -genetic influences may lead to crime as part id normal genetic variability with our species
  -genes do not cause crime but under particular environment influences they may give rise to certain ways of behaving that are criminal under some circumstances

Question 8

explain the twin studies theory??

Answer 8

• allow researchers to examine and compare genetic and environmental influence to see if there is genetic link to crime
• two types of twins = monozygotic (identical) which share 100% DNA and Dizygotic which share 50% DNA
• if both tins show same characteristics there is said to be a concordance rate
• if higher concordance rate for MZ twins than DZ twins suggests genetic influence for behaviour

Question 9

how does this theory explain criminal behaviour??

Answer 9

• clear link of genetic influence towards criminal behaviour
• suggests certain genes exist in nervous system which produce traits that are causing criminal behaviour
• these genes are inherited and passed down generations