Practise Edexcel Psychology questions using twin studies to assess genetic relatedness, interpreting concordance and evaluating shared-environment limits.
Twin studies are often used by psychologists when researching aggression.
Describe how a twin study research method could be used in biological psychology, such as when researching aggression.
AO1 (4 marks)
Credit up to four marks for an accurate description.
For example:
- Twin studies use monozygotic (MZ) and dizygotic (DZ) twins to
help determine if aggression is due to nature or nurture (1).
Psychologists would record the aggression of both pairs of twins in
their study, for example through observations (1). The
concordance rates for aggression between monozygotic (MZ)
twins and dizygotic (DZ) twins is compared (1). If the
concordance rate is higher for monozygotic (MZ) twins, then
aggression is at least partly genetic (1).
Look for other reasonable marking points.
(4)
Explain one strength and one weakness of using a twin study research method in biological psychology.
(4)
Strength
Weakness
( )
AO1 (2 marks), AO3 (2 marks)
Credit one mark for accurate identification of a strength and a weakness
(AO1)
Credit one mark for justification/exemplification of the strength and the
weakness (AO3)
For example:
Strength.
- Confounding variables are more controlled, as the twins share the
same environment before they are born and very similar
environments after they are born (1), therefore it is a valid way to
determine whether aggression is due to nature or nurture as it has
higher internal validity than some other research methods (1).
Weakness.
- Twin studies often base the identification of a pair of twins as
monozygotic (MZ) or dizygotic (DZ) on similarities in appearance
rather than DNA, which can affect the results on aggression (1),
so may influence the validity of any findings on aggression as
some twins may have been incorrectly labelled as monozygotic
(MZ) or dizygotic (DZ) (1).
Look for other reasonable marking points.
(4)
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