Aggression And Schizophrenia Study Flashcards
What is Monozygotic twins ?
Identical twins
- share 100% the same genetic makeup
- come from one zygote
What is dizygotic twins (DZ)
- non identical twins
- share 50% genetic makeup
- 2 zygote fertilised at the same time
Pros of twin studies
- generate large volume of data
- genetic components may be involved in a wide range of psychological phenomena
How is generate large volumes of data an advantage of twins studies?
- e.g. kindler study = used 1588 twins investigate factors affect patterns of sexual orientation in family
Bailey = studied 4901 Australian twins on sexual orientation - very large sample used . T/ F representative and generalisable = increase reliability of data
SHW of genetics can be involved in a wide range of psychological phenomena
E.g. Hettema study = found MZ twins are more similar when facing to fearful stimuli e.g snake than DZ twins
T/F, can be useful on therapeutic intervention in behaviour that can be treated with drug
Cons of twin studies
- MZ twins usually treated similarly than DZ twins
- separated twins are often brought up in similar environments
- lacks population validity
How is MZ twins usually treated similarly than DZ ?
-MZ twins often being treated the same e.g. dress the same and same opportunities comparing to DZ twins
= t/f hard to distinguish rather behaviour is due to nature or nurture
How is separated twins often brought up in similar environment as a con ?
- brought up apart by different branches of the same family or by different families if adopted but the will still be a similar background and social class to be able to adopt a child
- T/F it’s hard to distinguish if characteristics is due to nature or nurture
How does twin studies lack population validity ?
- only a small proportion are twins e.g. out of 11, only 2 people have twin siblings
- t/f findings abut behaviour e.g. aggression is not representative to whole population and so findings cannot be generalised to explain certain behaviour is due to nature, not nurture
Aim of Brendgen twin study
- to investigate if social aggression could be caused by genes or the environment
- to see if social aggression shared the same cause as physical aggression and if one type of aggression leads to another
AO1 brendgen sample
- 234 twins sample, recruited from Quebec New Born twin study, all born Nov 1995 - July 1998
- longitudinal data collected, 5 times of age 5 months to 60 months and at 6 yrs old
AO1 procedure of Brendgen’s study
- ratings from teachers and peers
- T= agreements on statements on physical and social aggression taken from pre school social behaviour scale with 3 points scale e.g. ‘to what extent does the child get into fights ‘
- P = booklet given with photos of every child in class and asked to circle 3 pics that thought to be matched with 4 behaviour described e.g. ‘who often gets into fights’
AO1 findings of Brendgen study (4)
- a higher correlation between MZ twins rating on P.A than same sex DZ twins
- S.A are similar on MZ and DZ twins
- teachers find BOYS are P.A and GIRLS more S.A
- Peers find boys are P+S.A than girls
AO1 conclusion of Brendgen study
- a genetic predisposition to physical aggression but not S.A. Children who are more P.A more likely to be S.A too, suggesting of an interaction between genes and environment
Pros of Brendgen twin study (6)
- ecological validity
- standardised procedure
- practical application to society
- objective data
- no demand characteristics
- confidentiality
Cons of brendgen twin study (6)
- lack pop validity
- lack mundane realism
- age of children studied
- cannot establish cause and effect
- limited controls
- protection from harm
How is brendgen study having objective data ?
- he gained two different info on social and physical aggression from peers and teachers, this shows thy are validating their findings which should eliminate bias and produce objective data
- t/f, increases internal validity
How is brendgen study practical application to society ?
- found strong correlation between genetics and physical aggression that can lead to S.A. If a child is showing P.A tendencies then they can be early educated to overcome it before it likely to develops S.A
- t/f, this can be used for an early indicator for parents and teachers about children’s problematic behaviour and can intervene early on before it turns into a habit
How is the age of children studied affect generalisability ? (Cons)
- only study aggression among 6 years old children = will have different findings at other ages
- other study suggest that P.A reduces as children start school and S.A does not fully develop until age of 8
- T/f, suggests aggression would be different at different age = unrepresentative =cannot be generalised to other age groups, only applicable to 6 years old
How is brendgen study had limited control ?
- not all twins had DNA testing to be MZ twins, some DZ twins may have been mistaken and placed into MZ groups
- T/f, conclusions about genetic relatedness may jot be accurate so reduces internal validity of findings
Purpose of Adoption studies
- used to compare characteristics of children from their adoptive parents and their biological parents
- concordance Rate high in adoptive parents and child = conclude nurture
- concordance rate higher in biological and child= conclude nature
Evaluation of general adoption study
+ most direct comparison of the influence of nature and nurture
- population validity
How is adoption study lack pop validity ?
- it only look at people characteristics who were adopted. Not everyone is adopted
T/f, the sample used is unrepresentative and cannot be generalised to whole population about certain behaviour
AO1 aim of Heston adoption study
To investigate the role of nature and nurture in the development of schizophrenia
To see whether schizophrenia has a genetic predisposition
AO1 procedure of Heston adoption study
- opportunity sample of 58 p.pants born between 1915-1945 from schizophrenic mothers from Oregon state psychiatric hospital, matched with control groups with similar characteristics e.g. sex
- all separated from mothers within 3 days of birth, all were given up to adoption by their mothers
- looking at official documents e.g. police records and personal interview with final 47 p.pants using MMPI and IQ score
- 3 psychiatrists including Heston and hospital diagnosis to evaluate profile blindly and independently to confirm their diagnosis of schizophrenia
AO1 findings of Heston study
- rate of schizophrenia with schizophrenic mothers = 10.6%
- rate of schizophrenia with control group =0%
- 4 adoptees had IQ lower than 70= suggests mild mental retardation
- average psycho social disability was 65.2 vs control 80.1 = troublesome
AO1 conclusion of Heston adoption study
- schizophrenia has a strong genetic predisposition which inheritance contributes to psych social disability.
- Yet half of adoptees became successful adults with artistic talents which wasn’t found in control groups
Pros of Heston study (5)
- matched control groups
- standardised procedure
- inter rater reliability
- no demand characteristics
- consent
Cons of Heston study (3)
- correlational data
- population validity
- cause and effect
How is Correlational data a negative in Heston study ?
- only found 10.6% concordance rate but doesn’t provide cause and effect conclusions for genetic predisposition and schizophrenia rates of adopted children
- t/ f, there can be other variables e.g. drug uses that could influence mental health of adoptees
