Twin and Adoption studies Flashcards
Twin and Adoption studies as a research method to investigate genetic links
Define Genotypes
the observable characteristics that comes from both parents e.g. eye colour, hair colour etc
Define Phenotypes
these are the things that make up said characteristics on the DNA level
Describe how Nature effects behaviour (biological cause)
the genes that we have inherited from both our biological parents influences behaviour
Describe how Nurture effects behaviour (environmental causes)
it means that upbringing is an important factor as it can easily result in someone to a normal citizen or a menace regardless of the who the parents are
Define DZ and MZ twins
MZ twins = are exactly the same genetically (same fertilised egg)
DZ twins = are basically just normal sibling (share 50% of DNA)
What is a concordance rate?
to measure if behaviour is genetics, shows that percentage of cases where the behaviour occurs in both twins, rather than just one
How do you read concordance rate?
MZ higher concordance than DZ = disorder has a genetic component
MZ concordance is the same or like DZ concordance = disorder is environmentally caused
MZ concordance is 100% = disorder is genetically caused
MZ concordance is significantly less than 100% = disorder has an environmental component
Twin studies Strengths
help identify trends in families e.g. Michael Corke’s Fatal Familial Insomnia (FFI) & the Bloomberg family who couldn’t stay awake in the evenings. when identified researchers can carry out DNA testing to try and isolate the genes involved therefore benefits society in identifying genetic markers where early intervention can be given
- results regarding the genetic basis of behaviour provide controlled evidence for the nature side of the nature/nurture debate as it demonstrates that much of our behaviour is inherited and not due to environmental influences enabling strong correlations to be identified in genetic explanation
- MZ twins share 100% DNA hence able to make a suitable assumption that if one twin has disorder then the other will have therefore carry out test to isolate the genes involved and make appropriate early intervention
- copious amount of secondary data that was gathered as quantitative data such as medical records, testing etc therefore treated as a valuable and reliable source of information to rely in the future
Twin studies Weaknesses
- concordance rate never 100% when comparing MZ twins = no seen as highly reliable if it was 100% in addition to credibility lowered as the claim of MZ twins claimed to be really similar
- difficult to separate genes and environment when studying MZ twins = really identical therefore if 1 factors changes the other twin have a high chance of developing it and if its an environmental factor the same result applies
- MZ twins likely treated the same as DZ twins = assume genetics isn’t the cause hence its environmentally caused and support that MZ twins aren’t completely genetically alike
Separated twin strength
deals with environmental issues because it supports that environmental factors has its influences and genes aren’t the only reason this can be seen due to MZ twins grew up together are more alike than those grown up apart
Separated twin Weaknesses
the odds of finding MZ twins that have been separated due to being of the same sex therefore deemed unreliable as you don’t have enough data to compare to see if it would cause and effect in addition to other researchers unable to do it themselves as well.
What are the AO1 similarities between twin studies and adopted studies?
Both use correlation techniques to draw a comparison between the twins
Both look for a concordance rate between biological parents and child
What are the AO1 differences between twin studies and adopted studies?
Correlation for adoption is between the parents and children but for twin studies its see to see if behaviour occurs in both twins or just the one
Adoption studies are carried out as the environment for adopted kids aren’t the same as their biological families
MZ are more than 50% genetically similar than DZ twins which is just 50%
Adoption studies Strength
Social responsibility is important for ethical research as thousands of kids gets adopted every for example 5330 was adopted in 2015 therefore it benefits society as it helps us understand how much or how little adoptive parents can do for the kids that they’re raising
children cant consent but adaptivity studies proceed with the presumptively consent of the adoptive parents and (where possible) the biological parents too in addition to anonymity is preserved and this respects their privacy and dignity.
adoption studies control for the environment as a confounding variable because when the kids are being adopted they don’t know if they’re going to a good environment or not in addition to if it is a good home but the parents attitudes change afterwards therefore implements methods to screen the possible parents that can provide a safe environment to grow
Adoption studies Weaknesses
adoption process is lacking as those kids that are being adopted could have had a even worse environment than those of their biological parents therefore not only can change the children’s behaviour to being anti-social but the kids are exposed to an environment that can also physically harm them
lack generalisability because the sample is heavily narrowed as the the main customers are those that cant have kids of their own due to infertility or those that had kids but lost them due to stillbirth hence relies on adoption therefore those it doesn’t demonstrate the environment on what a normal person would give the kids as the narrow sample are either bias/protective or have mental issues
adoption can cause a rift in families by drawing attention to the difference between the adopted kids and their step siblings or drawing comparison to the children’s biological parents therefore this allows self doubt to manifest which is a risk that the BPS warns about hence careful debrief is necessary
