The Biological Approach Flashcards
What does the biological approach assume?
- physiology and biology are at the root of all behaviour
- behaviour is influenced by : -
§- genes (implies a significant role of evolutionary adaptation)
§- biological structures - nervous and endocrine systems
§- neurochemistry - influence of chemic;s in the brain
how many pairs of chromosomes do people have?
23
genotype
genetic code that is written in the DNA of all the cells in the body
- dictates characteristics like eye colour
phenotype
the expression of the genotype
- physical appearance
- often the result of interaction between the genotype and the environment
How can we study the influence of genes?
- family studies
- twin studies
how do family studies show the influence of genes?
A particular trait could be found to occur more frequently within a family than within the general population, implying that genetic inheritance has played a role in the trait.
example of family studies
Lewis (1936) examined patients with OCD and found that 37% of the patients with OCD had parents with the disorder and 21% had siblings that suffered.
- difficult to tell whether genetic or environment as families spend a lot of time together.
monozygotic twins share ___% of their genes
100
dizygotic twins share ___% of their genes
50
Define concordance rate
The likelihood that the same trait will be present in both members of a pair of twins.
- expressed as a percentage
How do twin studies tell us the influence of genes?
There is an assumption that twins share the same environment. Therefore, the difference between concordance rates for MZ and DZ twins tells us how much influence genes have on that trait.
What did Nedstadt et al (2010) investigate?
What were the results?
The concordance rate for OCD in MZ and DZ twins
- MZ had 68% concordance rate
- DZ had 31% concordance rate
What points can we conclude from the Nedstadt et al (2010) investigation?
- Genes do play a role in OCD as MZ twins have a higher concordance rate.
- Concordance rate is not 100% suggesting that other factors must have a role in OCD.
what is the central nervous system?
Neurons in the brain and the spinal cored
what is the peripheral nervous system?
Neurons throughout the rest of the body
What is behaviour the result of ?
The CNS sending electrical messages to muscles, organs, glands etc. to influence a particular response.
How does neurochemistry influence behaviour?
When a nerve impulse reaches the end of one neutron, a chemical called NEUROTRANSMITTER is released. It travels from one neuron to the next across a junction called a SYNAPSE.
Different neurotransmitters affect behaviour in different ways.
Examples of neurotransmitters -
Dopamine
Seratonin
How does the endocrine system influence behaviour ?
- The glands that release hormones into the blood
The nervous system can signal glands to release hormones into the bloodstream which then have effects on our behaviour.
Examples of hormones
adrenaline
progesterone
melatonin
testosterone
Strengths of biological approach -
- Adopts scientific objective methods of investigation. Therefore, the biological approach is based on reliable data. There is significant evidence for a biological basis to a wide range of traits and disorders.
- Provides clear predictions of behaviour and so it has led to real life applications. Understanding the biological processes in the brain has led to the development of psychoactive drugs that treat mental disorders.
Limitations of biological approach -
- Twin studies are often used to provide evidence of a genetic basis to behaviour. However, it is assumed that each twin in a pair experiences the same environment. When in face MZ twins may tend to be treated more similarly then DZ twins leading them to have different environmental influences. So environment found affect the concordance rate as well as genes.
- Some of the explanations are too simplistic and cannot fully explain complex human behaviours. It is said to be reductionist as it reduces behaviour to the most basic biological components (genes and chemicals). Therefore, fails to consider other influences on behaviour e.g. cultural variation.
