Biological Approach Flashcards
Biological approach assumptions
- biological factors are main cause of behaviour
Body is made up of … each containing …
Cells = 23 pairs of chromosomes in each cell
DNA is
= A chain of 2 or more nucleotides joined together
- each cell has exactly the same DNA
DNA is divided into segments called… which control
Genes = control production of 1 specific protein
What are Alleles
Different versions of a particular gene, explains why ppl look different
What is genetic variation
= when a gene has different possible alleles
Sex cells
Woman = eggs
Men = sperms
- contain 23 chromosomes until reproduction when egg and sperm meet making 46 in total
What is genetic inheritance
When traits are passed down from parent to child
What is a genotype
= Description of all genes + alleles in body -> inherited from parents
What is a phenotype
= Persons traits (physical + physiological)
- controlled by both genotype and environmental factors
What do genes do
Control production of proteins = keep us alive + control our physical characteristics
Determine behaviour by affecting processes inside brain
What has the bigger impact on behaviour
Environmental factors than physical traits
Monozygotic twins
- identical twins
- share 100% of DNA
- come from 1 zygote which splits into 2 identical zygotes
Dizygotic twins
- non identical twins
- share 50% of genotype
- come from 2 different zygotes
What is the difference between shared and non shared environment
Shared = environment that a pair of twins have in common
Non shared = environment that a pair of twins don’t share in commmon
What is concordance
When 2 twins share the same phenotype
What is concordance rate
= % of twins who share a characteristic given that at least one twin has the characteristic
MZ + DZ twins have similar amounts of
Shared environment
Twin studies
Don’t include sets of twins where neither twin has the trait we’re studying
When does genetic variation contribute to a trait
- If concordance rate for monozygotic twins is > concordance rate for dizygotic twins
- Bigger the difference in concordance rate, the more influence genetic variation has on the trait
McGuffin (1996) method
Recruited bunch of MZ + DZ twins for which at least 1 twin has depression
McGuffin (1996): found
- if 1 MZ twin has major depression, 46% chance other twin had depression too
Concordance rate = 46% - if 1 DZ twin had major depression, 20% chance other twin had depression too
Concordance rate = 20%
McGuffin (1996): conclusion
~ genetic variation contributes to depression as concordance rate for MZ twins was bigger that for DZ twins
~ environmental factors still play a role in depression as concordance rate was not 100%
-> major depression is partially influenced by genetics
McGuffin (1996): limitations
- MZ twins might share more of their environment than DZ twins as they tend to be treated more similarly = bigger concordance rate in MZ twins might be partly caused by more similar environment
What is evolution
= When species gradually changes over many generations
What is natural selection
= When traits which increase chance for survival are passed onto future generations + species gradually adapt to their environment
* species genotype is determined by natural selection
What happens after DNA mutates
Creates a new/different version of the gene, new gene allele is created can happen during reproduction
-> when it happens over many generations, more likely to survive + reproduce passing on allele to future generations
How do natural selection/evolution shape our behaviour
-> causes have certain genes that control processes in Brain
-> processes in brain causes behaviour
What is biological determinism
Behaviour is determined by biological factors, such as our genetics
Limitations of biological approach
- overly reductionist = ignores social + cultural causes of behaviour
- biologically deterministic = don’t have ability to change/improve
-> Not held accountable for behaviour / can be excused/ can be discriminated
Strengths of biological approach
+ help understand + treat mental disorders/genetically inherited conditions
+ very scientific = gather objective + empirical data
-> control extraneous variables
-> can test cause + effect relationship
-> standardised procedure = easily replicated
