Biological Approach Flashcards
AO1 - Assumptions
- biological
- inherited
- hormones
- interaction, nature + nurture
- phenotype
- polygenics
- natural selection
- genes
What percentage of DNA do monozygotic twins and dizygotic twins share?
MZ twins = share 100% of DNA
DZ twins = share on average 50% of DNA
What are monozygotic and dizygotic twins?
MZ twins are identical from same sperm n egg.
DZ twins are non-identical from diff egg.
What does it mean if concordance rates between twins are 100%?
You can conclude that a behaviour/trait is ONLY due to genetics alone.
Environment has no role in behaviour.
What does it mean if concordance rates between twins are not 100%?
You cannot conclude that a behaviour/trait is due to genetic alone.
The environment plays a role in determining behaviour.
Candidate vs polygenic gene
A gene that codes for a whole behaviour.
Thousands of genes interacting together in complex ways.
Why is it that MZ twins are likely to have a higher shared environment compared to DZ twins?
Identical twins tend to dress in a similar way and draw similar reactions from people.
People treat them more similarly.
So same social groups, therefore similar environments.
What is meant by concordance rate?
The extent to which a pair of twins share similar traits or characteristics.
What is the key assumption in twins studies?
The only difference between MZ & DZ twins are how much DNA they share.
Their environments are the same.
AO1 - Methods of biological approach
key terms
- Brain scanning (MRIs, EEG, PET)
- Biochemical (saliva etc.)
- Physiological origins
- Monozygotic twins are found to have higher concordance rates as they share 100% of their DNA compared to dizygotic twins who share approximately 50%.
-genetic linkage and twin studies - evolutionary (trends)
What are the 4 AO3s?
AO3 - scientific (+)
AO3 - supporting evidence (+)
AO3 - reductionist (-)
AO3 - twin studies can’t disentangle nature from nurture
AO3 - scientific (+)
e.g. MRI, biochemical
empirical -> relicability -> reliability -> precise
AO3- supporting evidence (+)
e.g. agression candidate gene
psychological is biological assumption -> theoretical value -> explain n predict -> practical value -> credibility
AO3- too biologically reductionist (-)
e.g. candidate not only
decomposes -> disregards complexity -> polygenic -> assumes simplicity
AO3- twin studies nature vs nurture
e.g. MZ twins likely to draw similar reactions
environmental same -> not certain -> limits credibility
