Biological Approach

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  • Created by: Sam
  • Created on: 11-04-14 14:25

Biological Approach- Assumptions

1. BEHAVIOUR CAN BE EXPLAINED IN TERMS OF DIFFERENT AREAS OF THE BRAIN.

  • Research shown - different areas of the brain perform certian functions.
  • E.g the occipital lobe controls vision. The hippocampus deals with the ability to form memories.

2. BEHAVIOUR CAN BE EXPLAINED IN TERMS OF HORMONES.

  • Action of hormones- controls human behaviour.
  • Hormones- chemical substances that circulate the blood, affect target organs- lots are produced but disappear quickly, effecrs are slower than nervous system, but very powerful.
  • E.g Testosterone - linked to aggressive behaviour.

3. BEHAVIOUR CAN BE EXPLAINED IN TERMS OF NEUROTRNSMITTERS.

  • Human behaviour affected by nervous system. - neurons linked to each other communicate information. Linked by synapse. - neurotransmitters are chemical substances.
  • Electrical message from one neuron to another is transmitted across synapse by neurotransmitters.
  • E.g seroronin, controls happiness levels.
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Biological Approch: Selye's General Adaptation Syn

  • Hans Selye- medical doctor- noticed patients displayed same symptoms, whatever illness.
  • Suggested that body produces general response to stress. Response- adaptive helps body cope with extreme stress.

3 STAGES:

1. ALARM REACTION! - Stressor leads to response- hypothalamus sends signal to adrenal gland- adrenaline is released. Causes fight/ flight repsonse.

2.RESISTANCE! - If stress continues- body needs mean of coping with environment- body maintains normal internal functions (temperature)- despite appearance of coping - body is progressively losing resources (adrenaline other hormones like cortisol)

3. EXHAUSTION! - Body can no longer function normally- immune system no longer cope- stress related illnesses- cardiovascular disorder, depression.

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Biological Approach- GAS

Selye (1936) - used rats.

  • Exposed rats to bad experiences- extreme cold, drugs, excessive excesise, cutting spinal cord.
  • Rats responded with GAS.

STAGE 1 : 6-48 hours- lead on to physiological trias- enlargement of adrenal gland, ulcers, shrinkage of the immune system. 

STAGE 2 : Return to normal 

STAGE 3: Within 1-3 months, return of the phsiological triad. 

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Biological Approach- Strengths and Weaknesses

STRENGTHS: 

  • Scientific Approach- clear variables - cause and effect- e.g. recovery rates of psychosugery can be seen. 
  • Determinist Approach-  suggests that elements of the body e.g. hormones cause identifiable behaviour. E.g.high levels neurotransmitter dopamine are suggested as a cause of schizophrenia. - helps mental disorders be treated. 

WEAKNESSES:

  • Reductionist- Reducing complex behaviours in to simple explanations. E.g reducing stress to hormone adrenaline- may cause loss of understanding of mental disorders.
  • Individual Differences- Biological studies suggest everyones biological sytem acts in the same way. Nomothetic approach- E.g. male participants used more than female as hormones may affect research. E.g. some people may release more adrenaline in stress that others.
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Biological Approach- Methodology

1. BRAIN SCANNING- 

Links to Assumptions: Approach suggests behvaiour is caused by brain + nervous system- Biological psychologists look for methods to research this. 

  • EEG -elcotrodes on scalp- activity on different parts of brain can be recorded. Weakness: Recordings can't specifically indicate source of activity. 
  • CAT Scans- involves series of x-rays+ combining them to make 2D/3D picture of are a being scanned. Strengths: Higher quality images then x-rays Weaknesses: CAT scans - more radiation than x-rays. 
  • MRI scans - use of magnetic feild- causes atoms in brain to change alignment when magnet is on, and emit radio signals when magnet is off. Detectors read signals, map structure of brain. 
  • fMRI scans- gives both anotomical+ functional info - by taking repeated scans of brain. Strengths: More detail than CAT scans, no exposure to radiation. Weaknesses: Takes a long time. 
  • PET Scans - Giving patient slightly radioactive glucose- most active areas of brain use glucose+ radiation detectors can see radioactive glucose. Strengths: Reveals chemical info e.g. seeing between benign and malignant tumours. Weaknesses: Costly. 
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Behaviourist Approach - Methodology

2. Twin Studies

Link to Assumptions: Reasearches the influence of genes on behaviour. 

  • Comparing MZ and DZ twins: MZ twins share 100% of their genes (identical) DZ twins (nonidentical) share max 50% of their genes. E.g. a review of 30 studies (Bouchard and McGue) found 86 % correspondance between MZ twins and 60% for DZ twins in intelligence. Strength: Natural experiment Weakness: Similarities may be due to environmental factors, recent studies show MZ twins are significantly genetically different. 
  • MZ twins reared apart: separates influence of genetics + environment, Bouchard and McGue found 72% correspondance in MZ twins reared apart. Strenth: Attemps to control shared environment. Weakness: Samples very small. 
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Biological Approach- Psychosurgery

  • How it links to Assumption: The cause of mental illness can be located in areas of the brain. 
  • Aim: To treat some severe symptoms of mental illness- destroying areas of brain that cause behaviour. 

History: 

  • 40,000 years ago, trepanning- holes in to skull - relieve evil spirits. 
  • 1930's Moniz developed prefrontal lobotomy- based on treatment aggresive monkeys- behaviour improved when frontal lobe was removed. Moniz used same treatment on humans -icepick. 

Types Of Psychosurgery: 

  • Prefronal lobotomy- destroys connections to prefrontal cortex- mood regulation. Moniz drilled holes in each side of skull and inserting 'ice pick' to destroy nerve fibres. Moniz later refined this by using a leucotome (wire loop) cuts in to white matter in the brain- sevres nerve fibres.(6% fatality rate, severe side effects COMER 2002) 
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Biological Approach- Psychosurgery

  • Stereostatic psychosurgery- more precise technique- MRI's locate exact points, and then connections are carefully carefully. E.g. OCD is associated with thalamus- Capsulotomy surgeon inserts probe in to capsule, heat tips, burn away tiny parts of tissue. (Cosgrove and Raugh 2001 capsulotomy was effective in 67% of OCD patients)
  • Deep Brain Stimulation- Doesn't involve tissue destruction- Sugeons place wires in brain- wires connected to battery back implanted in chest- batteries produce adjustable high frequency current that interputs circuit in brain. E.g OCD - if it doesn't work it can be removed. (Mayberg et al 4/6 patients with severe depression experienced 'striking remission' after DBS in frontal cortex.)
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