twin and adoption study

Question 1

what is monozygotic?

Answer 1

indentical twins

Question 2

what is dizygotic?

Answer 2

non-identical twins

Question 3

Gottesman and Shields AIM

Answer 3

Whether schizophrenia had a genetic basis. Recorded patients over a 16 year period

Question 4

G+S PROCEDURE

Answer 4

57 patients member of a twin 24 monozygotic and 33 dizygotic. Collected data by hospital notes,self -report questionnaire,interviews etc each proband (twin in hospital) and their twin categorised
Category 1 Proband and twin hospitalised and diagnosed with schizophrenia
Category 2 both hospitalised but other twin have different diagnosis similar to schizophrenia
Category 3 co-twin psychiatric abnormality but nothing related to schizophrenia
Category 4 proband schizophrenia and other clinically normal

Question 5

G+S RESULTS

Answer 5

Concordance rates for schizophrenia higher for females compared to males for both MZ and DZ
Concordance rates higher for both MZ and DZ for severe schizophrenia (MZ-75% AND DZ 22%) compared to mild (mz 17% AND dz 0%)

Question 6

G+S Conclusions

Answer 6

Schizophrenia does have a biological basis however not totally caused by genes as the concordance rate for MZ twins wasn’t 100% so genes are only a risk factor.

Question 7

Define authoritarianism

Answer 7

Expecting or requiring people to bey rules or laws whilst minimising personal freedom

Question 8

Define conservatism

Answer 8

A general preference for the existing order of society and an opposition to efforts to bring about sharp change

Question 9

Define religiousness

Answer 9

Relates to a way of life dedicated to religion and the views associated with it

Question 10

Aim of Ludekes’s study

Answer 10

Determine whether people’s attitudes could be influenced by their genes, in particular traditionalism by examining MZ and DZ twins that had been separated at birth

Question 11

Procedure of L study

Answer 11

Studied 66 MZ and 53D, members of Minnesota study of twins reared apart group and filled various self-report measures to determine their attitudes towards authoritarianism, conservatism and religiousness

Question 12

Results of L study

Answer 12

Strong positive correlation across all scales in MZ while only conservatism scored strongly for DZ

Question 13

Conclusion of L’s study

Answer 13

Suggests that genes do have an influence on people’s attitudes towards traditionalism + researchers are confident this isn’t due to twins sharing same experiences growing up as they grew up in a different environment

Question 14

Strength of twin studies

Answer 14

• Scientific red is high, empirically study influence of nature v nuture and produce objective quantitative data eg G&S found concordance rate for severe schizo high in MZ 75% compared to DZ 22% showing it’s not caused by genes as it wasn’t 100% for DZ
• Practical applications eg seeking treatment

Question 15

Weaknesses of twin studies

Answer 15

• Scientific cred lowered by cofounding variables, small sample, atypically as most ppl aren’t twins eg G&S 57 twin pairs and most people aren’t twins means any results showing a genetic element can’t be generalised

Question 16

Strength of adoption studies

Answer 16

• Scientific cred is high, clear isolation of environmental influence, because if twin pairs were similar even if they didn’t share an environment researchers can be sure of the validity of results that genetics are a main influence eg Ludeke findings showed genes do have an influence

Question 17

Weaknesses of adoption studies

Answer 17

• Cofounding variables adoptive families chosen bc of similarities to bio fam + child may of spent time with bio fam before adoption so validity is lowered
• Generalising , samples are small and atypical results can not be generalised