A-level Psychology key content part 5

who identified 2 mechanisms where change occurs in a species

darwin

what are the 2 mechanisms Darwin identified

when environmental resources are scarce

animal/human need for food, shelter and resources

what do those most likely to survive pass on

genes to their offspring “survival of the fittest”

what is sexual selection

where more desired characteristics lead to better offspring qualities

how do biological psychologists study influence of genes on behaviour

family and twin studies

gene mapping studies

how do you carry out a family/twin study

examine concordance rates in order to influence the influence on individuals

how do you carry out gene mapping studies

finding specific genes that are more common in people with a certain disorder than in people who don’t have it.

what are concordance rates

the extent/degree to which 2 genetically related individuals show the same characteristics / behaviour disorder

what does concordance mean

agreement

how might a concordance rate be measured

a fraction or a probability

what is the reasoning behind genetic studies

behaviour or characteristic is genetic then the closer someone is with that person the higher the likliness they will inherit it

what is the concordance between first degree relatives

parent / siblings is 50%

what is the concordance between second degree relatives

nieces and nephews 25%

what do family studies do

predict the likeliness the person is to have the characteristic or behaviour in later life or undiagnosed

what % likeliness do first degree relatives of OCD sufferers have of catching/developing OCD compared to general population

11.7% compared to 2.7%

who came up with the theory that the closer related you are the more likely you are to catch OCD

nestadt et al

what do twin studies do

co9mpare differences in concordance rates for identical (monozygotic twins MZ) vs non identical (dizygotic DZ)

Which type of twins share 100% of genes

monozygotic

what did miguel et al find

53-87% concordance rate for OCD for MZ twins compared to 23-45% rate for the DZ twins

what did McGuffin et al find

47% concordance rate for MZ twins and a 20% concordance rate for DZ twins for depression

where is concordance rates highest

between MZ twins compared to DZ twins

as concordance rate isn’t 100% what does it suggest

other factors e.g. environment play a factor in rates of OCD and Depression

what is a genotype

the genetic code that is written in the DNA of individuals cells, the structures and behaviours are embedded in our genetic material

what is a phenotype

the observable physical/psychological characteristics of an individual as a consequence of the interactions with environment

what’s an example of a phenotype

internal environments can be affected by maternal exposure to disease or toxins

example of an environments influence on a phenotype

eye colour + environment = eye colour (brown)

example of an environments influence on a genotype

height (6ft) + lack of healthy food/sleep + height (5,5)