The Biological Approach Flashcards
Outline the assumptions of the biological approach (AO1)
> Explains behaviour mainly in terms of biological factors (e.g. genetics, hormones, neural, and evolution)
> The changes in inherited characteristics in a population over generations is known as evolution, and plays a role in behaviour.
> There is a direct correlation between brain activity and cognition.
> Hormones can also affect behaviour.
> Behaviour can be inherited through genes passed down from parents to offspring,
E.G. the candidate gene MAOA-L gene codes for aggression.
> Through polygenics behaviour is the result of thousands of genes interacting together in complex ways.
> The phenotype is determined by both the genotype and the environment combined.
How much DNA do monozygotic twins and dizygotic twins share?
MZ twins = share 100% of DNA
DZ twins = share on average 50% of DNA
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.
What is meant by a candidate gene?
A gene that codes for a whole behaviour.
E.G. MAOA for aggression
What is meant by polygenic?
Thousands of genes interacting together in complex ways.
What are monozygotic twins?
Twins that come from one fertilised egg that split into two.
What are dizygotic twins?
Twins that come from two separately fertilised eggs from different sperm.
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 the key assumption in twins studies?
The only difference between MZ & DZ twins are how much DNA they share.
Their environments are the same.
What is meant by concordance rate?
Concordance rates = agreement between.
The extent to which a pair of twins share similar traits or characteristics.
Outline the methods used by the biological approach (AO1)
> The biological approach can be studied using genetic linkage studies and twin studies to explain genes.
> For twin studies, it’s assumed that the only difference between monozygotic and dizygotic twins are how much DNA they share, and assume both types of twins share the same amount of environment.
> Monozygotic twins are found to have higher concordance rates as they share 100% of their DNA compared to dizygotic twins who share approximately 50%.
> If the concordance rate is 100%, then we assume that behaviour is purely down to genetics alone.
> Neural explanations rely on brain imaging techniques such as fMRI and PET scans.
> Hormonal explanations tend to use blood samples to determine levels of hormones in the blood.
> Evolutionary explanations of behaviour are slightly more difficult as it relies on psychologists studying trends over time.
What are the examples of biological factors that can affect behaviour?
Genetics
Hormones
Neural (e.g. brain)
Evolution
How are hormonal explanations of behaviour derived?
Using blood samples to determine lvl of hormones in blood.
How are neural explanations of behaviour derived?
Using brain scanning techniques (e.g. fMRI or PET)
