biological approach

**Explain the assumptions of the biological approach**

* Brain structures/functions can explain thoughts, feelings & behaviours (have physical basis)
* Biopsycholgist agree gene influences behaviour
* We inherit genes from ancestors > behaviour/psychological characteristics have evolutionary explanations 

**Explain the influence of genes on behaviour**

* Nucleus of cells contain 46 chromosomes (23 pairs inherited from parents > genotype, form basis of developments)
* Chromosomes made up of DNA which carries genes
* Genes interact with environment to influence our bodily structure/function

**Explain genotype & phenotype**

**Genotype:** 

* individual genetic make-up
* occurs at conceptions
* provides genetic code fo development
* everyone has aprox 100,000 genes
* dictates characteristics e.g eye colour
* each individual has genotype that is unique to them (except identical twins)

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**Phenotype:**

* Product of what happens when genotype interacts with environmental factors

**Explain the evolution theory of behaviour**

**Main principle:** any genetically determined behaviour that enhances an individual’s survival & reproduction will be passed on in the genes to future generation i.e natural selection.

* E.g aggression, 

**Overall, evaluate the biological approach: deterministic**

**Too deterministic**

* E.g sees human behaviour as being controlled by internal, biological causes - no free will
* **Retz et al, concluded 5-httlpr gene is associated with violent behaviour in male criminals**
* Indicates violence is part of criminals biology - do not choose to act this way (no freewill)

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**Weakness,** has implications for legal system/wider society, rule of law = offenders are legally/morally responsible for their actions - biological control = blame on being controlled by genes

**Overall, evaluate the biological approach: evidence**

**Many supporting evidence**

* E.g comes from twins/objective studies using biological equipment (PET scans)
* Discovered concordance rates of depression; monozygotic twins - 49%, dizygotic twins - 17%, ordinary siblings 0 9%

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**Strength,** adds validity/credibility - particularly gene explanation

**Overall, evaluate the biological approach: application**

**Led to many treatments being developed to treat psychological disorders**

* E.g research into  biochemical process in the brain led to development of drug treatments - for depression/schizophrenia
* Drugs are not effective for all patients, they have revolutionised treatment for many

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**Strength,** suffers able to manage their conditions/live relatively normal life

**Overall, evaluate the biological approach: methods**

**Use scientific lab studies, involving scientific/biological equipment**

* E.g to investigate genetic/biological basis of behaviour - BA uses range of highly scientific methods which are reliable/objective
* **Raine et al 1997 used PET scans to compare brain activity in murderers/normal people**
* Found difference in areas of brain e.g prefrontal cortex (associated with aggressive behaviour)

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**Strength,** emphasis importance of scientific process, reliance on scientific methods give psychology greater credibility/status as a science .

**Explain Biological research: twin studies**

**Concordance rate**: extent to which both twins in a sample share a certain disorder/trait/behaviour.

* Concordant, both have it
* Discordant, only one twin has it

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Biopsychologists use non/identical twins to help understand genetic basis of certain behaviours

* Likelihood of non/identical twins compared gives indication to how much of behaviour may be genetic
* If MZ twins show higher concordance rate than DZ twins, argued there is an genetic explanation.

**Evaluate the use of twin studies in biological research: perfect participants**

**Identical twins share 100%, non identical share 50% of genes.**

* E.g **Bouchard & Mcgee** study of **intelligence,** clearly see that IQ has genetic basis: 27% difference between concordance rates of identical/non-identical twins raised together

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**Strength,** ideal sample = useful data

**Evaluate the use of twin studies in biological research: same environment** 

**Problem: identical twins are exposed to a similar environment when raised e.g parents dress them the same. This does not happen with non-identical twins.**

* E.g 87% identical twins in **Bouchard & Mcgee** study would have shared very similar experiences
* Perhaps environmental stimuli are reason why they had higher concordance rates

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**Weakness,** means findings could be easily interpreted as supporting nurture rather than nature.

**Explain Biological research: scientific equipment & scanning techniques**

Approach assumes behaviour can be explained **via brain activity/nervous system**, therefore use **scientific methods** to view brain activity

* E.g PET/MRI scans. EEGs (can study structure/function of brain)

**Evaluate the use of scientific equipment & scanning techniques**

**in biological research: objective data**

**Methods are precise, objective, highly scientific**

* E.g **raine’s study** used PET scans, data objective/not open to subjective intp

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**Strength,**  adds validity/scientific, biological equipment increases inter-rater reliability - all psychologists will intercept objective data the same.

**Evaluate the use of scientific equipment & scanning techniques**

**in biological research: Several weaknesses**

**PET scans: extremely costly, patient must be injected with radioactive substances, less accurate than MRI scans**

* E.g **raine’s study -** invasive method for Ps, before brain analysis will need radioactive substance injected into them

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**Weakness,** could cause already stressed patient more stress