All studies from biological psychology and theories including 2 strengths 2 weaknesses and a conclusion for each study or theory. Studies include simplified aim, sample, procedure, result and conclusion. Theories include at least 4 main points from it. Also a key question with 4x A01 4xA02 4xA03. A...
Biological Psychology
Twin Study Method
A01:
Twin studies compare behaviour between groups of MZ and DZ twins to look for shared similarities,
using concordance rates.
Concordance rates- a statistical calculation that works out the level of probability that the twins will
show similar behaviour.
Higher MZ- suggests that behaviour is genetic supporting nature
Higher DZ- suggests behaviour is due to environment and supporting nurture
Monozygotic twins- identical twins that share 100% of the same genetic material
Dizygotic twins- fraternal twins that share only 50% of the same genes as any two siblings
A03:
One strength of twin studies is that they are high in reliability to study whether behaviour is due to
environment or genetics, as more women are having twins due to the advancement of fertility
treatment, making it possible to research twins with larger samples. Therefore, it is easy to replicate
more studies with strong statistics to check for the consistency of data on the reasons behind some
behaviours and disorders such as schizophrenia.
One weakness of twin studies to study whether behaviour is due to environment or genetics, is that
it is low in controls as the results may be affected extraneous variables such as MZ/DZ twins being
treated differently to other siblings e.g., with fascination. This means findings on whether behaviour
is due to environment or genetics are low in validity as behaviour may be due to the way they have
been treated rather than genetics causing the behaviour to develop.
One strength of twin studies to study whether behaviour is due to genetics or environment is that it
uses quantitative data such as concordance rates which allow objective comparisons to made
between MZ and DZ twins behaviour. This means the results from the concordance rates collected
from twin studies are higher in validity as they can be statistically analysed without interpretation
bias which makes the study on whether behaviour is due to genetics or environment more accurate.
One weakness of twin studies to study whether behaviour is due to genetics or environment is that
they use a small sample of twins and twin’s behaviour may not be representative of other non-twins
as we are still learning about aspects such as twin bonding. Therefore, the results on whether
behaviour is due to the environment or genetics cannot be generalised to all children who are not
twins.
Conclusion
As it shows what behaviour is caused by so more accurate treatment method can be applied such as
drug treatments if the behaviour is due to nature or therapy/change in environment if the behaviour
is due to nurture
As there is always the risk that twin studies can be make twins feel unusual as they are being used
solely because they are twins which they cannot control
Ghottesman and Shields
A01:
Aim- to investigate if schizophrenia had a genetic basis
Sample- 62 schizophrenic patients with an equal number of males and females. 24 MZ twins and 33
DZ twins
Procedure: mental health was measured by hospital notes, semi-structured interviews with twins
and parents, 30-min tape recording, personality testing and psychometric testing.
Results- 55% of DZ twins have a mentally healthy twin compared to only 21% of MZ twins.
Conclusion- the closer the genetic link the more likely both twins are to show schizophrenic
symptoms.
A03:
A large sample of 62 was used including different ages and both male and female patients to see if
schizophrenia had a genetic basis. This means the findings on whether schizophrenia has a genetic
, basis have higher population validity for males and females experiencing schizophrenia who have
twin.
The 30-minute tape recording to study if schizophrenia has a genetic basis may lead to researcher
bias when interpreted as qualitative data is very subjective. This means that the findings on if
schizophrenia has a genetic basis are lower in validity as they could be interpreted wrongly and
therefore less accurate.
The study on whether schizophrenia has a genetic basis used several methods such as hospital
notes, semi-structured interviews with twins and parents and a 30 min tape recording. This means
that findings on whether schizophrenia has a genetic basis can be compared to triangulate the
findings, increasing the reliability.
The sample on the study on whether schizophrenia has a genetic basis only focuses on twins in
London, which means that the findings are not representative of people outside of London.
Therefore, the findings on whether schizophrenia has a genetic basis are not generalisable to the
wider populations such as non-twins in the USA.
Conclusion
As it means doctors can identify at risk people of developing schizophrenia if they have someone
else in their genetic family with it and watch for early symptoms that might have gone unrecognised
otherwise
As it fails to look at reasons for schizophrenia so preventive action cannot be taken as it just
identifies a concordance between schizophrenia and genes
Adoption Study Method
A01:
Adoption studies measure whether behaviour is due to nature or nurture. Group of adoptees are
studied, and their behaviour is then correlated with their adopted families as well as their natural
families.
Adopted family- Share no genetic material with their adopted families but share their environment
Biological family- Share 50% of their genes with each biological parent but would not have lived with
them for most of their life
More like adopted family then behaviour is due to the environment and supports nurture. More like
biological family then behaviour is due to genetics and supports nature.
A03:
One strength of adoption studies to study whether behaviour is due to nature or nurture is that
children are observed in their typical environment of their family, school or home environment. This
means that these studies are high in ecological validity as the results are representative of real life
and has mundane realism, so the adoption study method on whether behaviour is due to nature or
nurture is more accurate.
One weakness of adoption studies on whether behaviour is due to nature or nurture is that not all
children are adopted at the same age, so the impact of the biological parents may be profound for
some children than others. This is a weakness because it fails to control the effect of extraneous
variables such as biological parents influence so it may be more difficult to understand whether
behaviour is due to nature or nurture making the adoption study method less accurate.
One strength of adoption studies to see whether behaviour is due to nature or nurture is that it uses
a standardised procedure to study adoptees behaviour and characteristics, which are then
correlated with their adopted families and their natural families. This means that the research on
whether behaviour is due to nature or nurture can be easily replicated to check for consistency.
One weakness of adoption studies to see whether behaviour is due to nature or nurture is that they
are not representative of all children as the participants are adopted and living apart from their
biological parents. This means that the results on whether behaviour is due to nature or nurture
cannot be generalised to all children such as those who live with their biological family, which makes
the adoption study method less accurate.
Conclusion
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